Krepost Sveaborg
Encyclopedia
The Krepost Sveaborg was an Imperial Russian
land and sea fortress constructed around Helsinki
during First World War. The purpose of the fortress was to provide a secure naval base for the Russian Baltic fleet
and to protect Helsinki and block routes to Saint Petersburg
from a possible German
invasion. Krepost Sveaborg was part of the Peter the Great's Naval Fortress
, a coastal fortification system protecting access to Saint Petersburg by sea. The central part of Krepost Sveaborg was the old fortress of Suomenlinna
where the fortress headquarters were located. Due to technological advances in artillery the old fortress was no longer capable of providing a sufficient protection, and a new main defensive line was built well beyond the old fortress boundaries. New coastal artillery
guns built on outlying islands protected Krepost Sveaborg from the sea, while fortified lines constructed around Helsinki were intended to stop any attacks on land. The primary coastal guns were 10 in (254 mm) model 1891 guns and 6 in (152 mm) model 1892 Canet guns. Older 11 in (279 mm) model 1877 guns were also used. In summer 1917 the fortress had two hundred coastal or anti-landing guns, of which 24 were 10 inch guns in six batteries, 16 were 6 inch Canet guns in four batteries and twelve were 11 inch guns in three batteries. The artillery used in land fortifications included older coastal guns, old fixed carriage guns and newer light field guns. In March 1917, Krepost Sveaborg had a total of 463 guns, although many of them were obsolescent. Krepost Sveaborg was still partly incomplete in 1917 when the February Revolution
halted most of the construction work. Some further construction work was carried out during the remaining year, but all work halted during the October Revolution
. Following the Finnish Declaration of Independence, parts of the land fortifications were used in the Finnish Civil War
. The coastal fortifications were later taken over by Finland to protect Helsinki, while the land fortifications were mostly abandoned and disarmed.
had ceded Grand Duchy of Finland
to Russian Empire
as the result of the Finnish War
of 1808—1809 and along with it the fortress of Sveaborg, , the present day Suomenlinna. The fortress protected the southern Finland and became a naval base for the Russian Baltic Fleet. After the end of the Napoleonic Wars
many new buildings were built to improve the living conditions on the fortress, but the fortifications were neglected. After the start of the Crimean War
in 1853 construction of new fortifications began on the other nearby islands and on the southern shore of Helsinki peninsula. In 1854 an Anglo-French naval fleet entered the Baltic Sea
, hastening the work. These fortifications protected the flanks of the fortress and provided depth to the defence, but the problem of obsolescent artillery was not solved. Thus when the fleet attacked the fortress on the 6th of August 1855 they were able to bombard the fortress for two days from a distance of 4–5 km (2.5–3.1 mi) while the best Russian guns had a maximum range of 2500 m (8,202.1 ft).
After Crimean War fortifications of Viapori were improved by building artillery casemate
s and new bomb-proof buildings. Vallisaari just east of Suomenlinna was the site of the first new construction works. The harsh suppression of the Polish
January Uprising
of 1863 and the resulting criticism soured the relationships between Russia and western Europe and hastened the fortification works. Between 1863 and 1864 redoubt
s were built on Vallisaari, Kuninkaansaari and Santahamina islands. In 1860s and 1870s Russia purchased and then built under license new Prussia
n Krupp
rifled breech loading guns which were also used in Viapori. A total of 32 new bomb-proof stone powder cellars were built by the beginning of 1870s, further improving the defences. The Russo-Turkish War of 1877–1878 was the next crisis that threatened the peace between Russia and England, with new batteries being built at Viapori on Kuninkaansaari and older ones improved or rebuilt. New technology in the form of telegraph
, railway lines and searchlight
s began to be used. Improvements in artillery and ammunition forced improving the gun positions by covering the old walls and fortifications with a thick earthen walls. With high-explosive shells appearing at the end of the 19th century earth and stone were no longer sufficient and first concrete fortifications with steel doors were built in Viapori. Continually improving guns resulted increased range, necessitating rangefinder
s, while heavier guns and ammunition required improving piers, roads, cranes and ammunition carts to transport the guns or move ammunition from magazines to guns. Despite the improvements the funds and resources allocated to the fortress were not sufficient to keep pace with the evolution of military technology. While parts of the fortress or were improved and new weapons or equipment were received, the overall condition of the fortress became ever more obsolescent, and the vulnerability of the flanks and rear were a lasting problem. By the end of 1880s and early 1890s Viapori could no longer be considered a proper fortress but only a coastal position, capable of defending only against an enemy coming directly from the sea. The primary role of the fortress became more one of internal politics, as it helped the Russians maintain control of Helsinki.
, and the Kronstadt
fortress protecting Saint Petersburg, relegating Viapori to a secondary status. After the losses during the Russo-Japanese War
and in light of the rising might of the Imperial German Navy
, Liepāja was considered too vulnerable for a main fleet base, and the decision to build Peter the Great's Naval Fortress was made. In the new plans the main line of defence against the enemy was at the Porkkala
-Tallinn
line with Tallinn also the new main base for the Russian Baltic Fleet. Helsinki was to be a base for torpedo boat flotillas. The construction of the Tallinn naval base was delayed however, and with the new ships being constructed to replace the losses suffered against Japan the Russian Navy was forced to rely more on Helsinki despite the obsolete armament and inadequate fortifications at Viapori. As the threat of war in Europe grew, it became essential to expand the fortress to provide a necessary protection for the naval base. Until 1910, when the first 152 mm Canet guns arrived, the only modern weapons at Viapori were 57 mm quick fire guns
with the rest of the artillery designs dating from the Russo-Turkish War. The first new 254 mm guns arrived in 1913, but it was not until early 1914 that construction of the first new batteries began on Melkki and Isosaari. During the First World War the new Krepost Sveaborg was built to substantially expand the old fortress. A new main line of defence was constructed on the outlying islands, pushing the defensive line several kilometers southward, thus providing a secure outer anchorage south of the old fortress for larger warships without the need to navigate the narrow straits leading to the inner anchorage at Kruunuvuorenselkä. The older parts of the fortress became a second line of defence and the main storage areas. The rear of the fortress was finally protected by land fortifications, at first field fortifications on the Helsinki peninsula built in 1914, and, later, an outer line of fixed fortifications.
. In summer 1916 Krepost Sveaborg was subordinated to Baltic Fleet. At the start of the war Krepost Sveaborg was divided into three defensive areas, with the sea front forming one defensive area and the land front divided to Pasila
and Laajasalo
-Herttoniemi
areas. The sea front was further divided into six sectors, with sectors 1-4 at the old fortress, sector 5 at Melkki and sector 6 at Isosaari. The sea front was divided into main line of defence from Melkki to Isosaari and second line of defence from Lauttasaari
to Santahamina
at the end of 1914. As the new batteries were constructed Melkki was relegated to second line of defence and Lauttasaari to land front in spring 1915. At the land front new defensive lines were constructed from 1915 onward further away from the city center. The new land front was divided into three sectors: eastern, northern and western. Krepost Sveaborg was also responsible for a larger fortification district that included coast line west of the fortress until Hanko.
At the start of the war the fortification artillery units manning the fortress were organized into nine artillery companies and a machine gun detachment. In April 1915 the fortification artillery units were reorganized into a single fortification artillery regiment with three battalions and a machine gun company. Four companies manned the coastal forts at sea front. In June 1916 the regiment was divided in two, with 1st regiment responsible for the seaward defence and the 2nd for the landward defence. Both regiments had ten companies in three battalions. The 1st regiment was divided into three defence detachments, with south-western and south-eastern detachments responsible for the main line of defence on the outlying islands with the newest guns, while the third detachment manned the second line on the old fortress. The artillery regiments had a common supply unit responsible for the weapons, ammunition, transportation between islands etc. A signals company built and maintained the communication lines. The minefields
around the fortress were built by the Krepost Sveaborg mine company, from 1915 a mine battalion. In 1916 the fortress was reinforced by the mine battalion from Vladivostok
fortress. Construction and engineering department of the fortress headquarters organized the construction works of the fortress with engineering and sapper units as well as the civilian workers.
Infantry units at the fortress manned the landward defences and provided detachments on the coastal forts for anti-landing and close defence duties. The peacetime Krepost Sveaborg fortress infantry regiment was reinforced by conscript units, which in 1915 were organized as the 427th and 428th infantry regiments to a new 107th infantry division which was sent to front line after a training period. In spring 1916 regiments from the new 116th division manned the fortress. At the autumn of 1916 units from different fortresses were brought to Krepost Sveaborg and organized into the 128th infantry division. In July 1917 the fortress was manned by the fortress infantry regiment and the 428th Lodeynoye Pole infantry regiment of the 128th division. In October 1917 the 128th was replaced by the 29th infantry division, badly mauled at the front and brought to Krepost Sveaborg for rest. At January-February 1918, when Finland gained its independence, Krepost Sveaborg had six infantry regiments: the 696th revolutionary regiment, the fortress infantry regiment and 113th, 114th, 115th and 116th regiments of the 29th infantry division.
Construction workers included Russian soldiers but also Finnish civilian workers and forced labour using prisoners transported from far east. Finns were exempt from conscription, and thus there was available manpower for fortification works. The payment for fortification works was slightly above average for manual labour, and made it an attractive option particularly for many rural workers. In 1915 when large scale construction of fortifications around Finland began Russians instituted a work responsibility for Finns based on wartime emergency law to obtain the necessary labour force. To ease the manpower shortage Russians brought convicted prisoners from far east to Finland in summer 1916 as forced labour. Approximately 2000-3000 men, including Chinese, Kyrgyz and Tatars, were employed as lumberjack
s around Espoo and Sipoo
. Kyrgyz were mainly guards. Asian workers were transported back to Russia already in 1917 however, citing the workers to be unaccustomed to the northern climate and possible threat of rebellion. The total number of workers in not known, but an estimated 10 000 to 15 000 men were used in construction works around Helsinki and up to 100 000 total in Finland. Complicated bureaucracy delayed the construction works, and the supervision of the works was also poor leading to a wide spread graft.
, Isosaari (two batteries) and Itä-Villinki.
The 6 in (152 mm) 45 caliber model 1892 guns supplemented the 10 inch guns of the sea front main line of defence. These guns were French
Canet guns
and had a maximum range of 13–14 km (8.1–8.7 mi). Unlike the 10 inch guns, the 6 inch guns had a modern counter-recoil system and achieved a rate of fire of five shots per minute. The six inch guns were intended against destroyer
s and other smaller vessels. They were installed in four batteries of four guns each at the sea front on Miessaari, Harmaja
, Isosaari and Santahamina
. A fifth battery was under construction on the mainland at Skatanniemi cape. The guns for this battery arrived, bringing the total sea front number to twenty, but the construction was not completed before the war ended. Further seventeen guns on lower ship deck mountings with lower maximum elevation were used on the land front. The guns used at Krepost Sveaborg included both Russian Obukhov
licence-produced guns and French Schneider guns.
The older heavy coastal artillery pieces, the 9 in (229 mm) and 11 in (279 mm) model 1867 and 1877 guns and the 9 in (229 mm) and 11 in (279 mm) model 1877 coastal mortars, were mostly transferred to land front or placed in reserve. Three batteries (twelve guns) of 11 inch model 1877 guns were used throughout the war at the sea front second line of defence at Kustaanmiekka, Kuninkaansaari and Vallisaari. At the start of the war 11 inch guns were also used at the main line of defence on Isosaari before 10 inch model 1891 guns replaced them. Two batteries of 11 inch coastal mortars remained in use until 1916 in Vallisaari and Kuninkaansaari. The mortars were also capable of firing to the rear of the fortress and were intended to keep the citizens of Helsinki loyal. The heavy shells of the mortars were considered to have a "suitable moral effect" on civilians. 6 in (152 mm) 22 caliber siege gun model 1877
was primarily an army weapon used on wheeled carriage on land front, but some guns mounted on fortification mounts were also used on sea front at the start of the war.
Light coastal guns used at Krepost Sveaborg included 57 mm Nordenfelt
guns, fifteen guns at the beginning of the war and twenty by the end of the war. 75 mm (3 in) 50 caliber model 1892 Canet guns were similar to the six inch model 1892 gun. First of these guns arrived at 1914, and twelve coastal guns were used at Krepost Sveaborg, with an other eighth anti-aircraft gun versions with a 50° maximum elevation.
It was planned in 1916 to build four two-gun batteries of 12 in (305 mm) 52 caliber model 1907 guns at Krepost Sveaborg, but the work started in 1917 never progressed beyond building gun mount foundations and some ammunition and crew shelters. The batteries were to be built on the mainland, with guns in single open positions capable of firing on both land and sea targets. The batteries were located at Munkkiniemi
, Haaga
, Oulunkylä
and Koskela
. The 305 mm guns were used later to protect Helsinki however, as Finland built an armoured twin turret on Kuivasaari between 1931 and 1935 and two guns in open positions at Isosaari during the Second World War in 1941-1944.
version used on both field and fortress mounts and a lighter 120 pood barrel version on field carriage. 42 line
(107 mm (4.2 in)) battery gun model 1877 and 34 line (87 mm (3.4 in)) light field gun model 1877
were other older field artillery pieces used at the fortress. 76 mm model 1902 gun was a newer rapid fire field gun with a counter recoil system. The 76 mm model 1902 gun was also used as an anti-aircraft gun on a modified "Rosenberg" mount. The land front weaponry also included a variety of smaller caliber anti-storming guns, caponier guns and other mixed artillery pieces. The reserve guns included different older models up to bronze-barrelled mortars.
s were also used to protect Krepost Sveaborg from an attack from the sea. An outer line of contact mines was laid approximately 15 km (9 mi) outside the main line of defence. Shore detonated controlled mines
were used to create an inner mine barrier to protect the entrances to the outer anchorage. These mines were laid typically in three rows with 200 m (656 ft) separation between rows and 60 m (197 ft) between mines in a row. Controlled mines required an extensive cabling system to the shore stations where the command to detonate the mines was given. Fortified electrical stations provided the necessary electricity for the mine control network. Electricity was also used for communication systems, searchlights, electrical ammunition lifts and in barracks and crew shelters.
, where the known base length is the height of the rangefinder
from sea level, were first used at Viapori in the 1880s. Vertical based rangefinders required only one instrument, but they were susceptible to interference from vibration caused by firing of the guns. Vertical based rangefinders also required a substantially high measurement site that was a problem on the low islands. To measure distance with reasonable accuracy to a target 10 km (6 mi) away the rangefinder had to be at least 10 fathom
s (21.3 m (70 ft)) and preferably 20 fathoms (42.6 m (140 ft)) high - often impossible to achieve. Measurement sites had usually the rangefinder on a stone or masonry column 110 cm (43 in) high lying on a granite foundation. The measurement pavilions had simple wooden walls and sheet metal roof protecting them from the elements and were 4–6 m² (43.1–64.6 sqft) in size. Vertical rangefinders were no longer used on the new forts built on the outer islands.
Distance measurement at the 10 in (254 mm) model 1891 batteries was based on horizontal triangulation
from two different points, a primary and secondary, on separate islands. The rangefinders used were general von der Launitz's models 1903 and 1905-07. The average distance between the two points at Krepost Sveaborg was 5.5 km (3 mi). Target information was sent from the primary point to the battery command point. If the primary point was located away from the battery or directing a different battery a rangefinder converter designed by colonel Kovanko was used to calculate the firing solution. A weakness in using two measurement points was that any malfunctions in either of the rangefinders or in the telephone system would render the system inoperable. Target indication between the primary and secondary points could also pose problems, as there would often be several similar target ships. The system was also not capable of measuring distances to targets in the rear of the battery; a maximum measurement sector was 140°.
On the smaller 6 in (152 mm) model 1892 Canet gun and anti-aircraft batteries 3 m (10 ft) wide Zeiss stereoscopic rangefinders
were used. Maximum distance that could be reliably measured with three meter rangefinders was 8–10 km (5–6.2 mi), while the maximum range of the six inch guns was 13–14 km (8.1–8.7 mi). A single 6 m (20 ft) rangefinder was used by the commander of the artillery in a central fire control station at Kuivasaari. Six meter rangefinders were also planned for the 10 inch batteries later in the war but never obtained.
s provided the necessary electrical power to operate the searchlights. Searchlights were used in disappearing positions, where the searchlight was normally in a shelter and only exposed when needed for illumination. The disappearing positions had two types: either the searchlight was raised from the shelter by a lifting mechanism, or it was moved by rails from the shelter to position.
s and signal flags were also used.
and Santahamina
by a scarce line of fortifications at Ruskeasuo
-Pasila
-Käpylä
-Koskela
-Viikki
-Herttoniemi
-Roihuvuori
. Lauttasaari
, Meilahti
and Laajasalo were also fortified to some extent. It was also planned to fortify Kulosaari
and Vartiosaari
. These first fortifications were field fortifications located 6–7 km (3.7–4.3 mi) from the city center, with the defence concentrated at fortified hilltop redoubt
s.
In early 1915 it was decided to build new defenses further away from the city center. The new defenses were stronger fixed fortifications with positions quarried into rock or dug into ground. Fortifications were built from wood and stone masonry as well as concrete. New fortifications had a network of defensive structures, with trenches, rifle pits, machine gun nests, barbed wire obstacles
, shelters and roads. Artillery batteries were located 0.5–1.5 km (0.310686368324903–0.93205910497471 mi) behind the front line, often located on reverse slope. Artillery batteries had 2-6, typically four, guns. Heavily fortified caponiers providing flanking fire were built on places of the front line. First a northern line was built at Leppävaara
-Kaarela
-Pakila
-Pukinmäki
-Myllypuro
-Vartiokylä
. Construction on a western line from Leppävaara to Westend via Tapiola
began shortly afterwards. In late 1915 it was decided to build an outer line of defence on the northern and eastern sectors, extending the fortifications northward and in the east from Pukinmäki to Malmi
, Mellunkylä
and Vuosaari
. Fortification works continued until the February revolution of 1917, and some work was done until early 1918. The land front was divided into three sectors, eastern, northern and western with 36 bases, numbered I-XXXVII. The bases were usually centered on hilltops with the strongest defences.
The basic front line fortifications were open or covered machine gun nests, rifle pits, observation posts and shelters. Most of the structures were designed to be covered with a concrete roof poured on wooden planks occasionally reinforced with railway tracks. Some of the positions were built with stone or logs. Many of the fortifications have been left uncovered however, built only to a point where adding the missing roof could be accomplished quickly. The basic fortified types are a type A square machine gun nest, type B square rifle or machine gun pit, type C rounded rifle or observation pit, type D oval rifle pit with several firing ports and types E and F large rifle positions for multiple shooters. There is considerable variation between individual structures among the basic types, with newer positions generally built larger and stronger.
The long range batteries of 10 in (254 mm) and 6 in (152 mm) guns included ten batteries with six 10 inch batteries and four 6 inch batteries, with one more under construction. The basic shape of the batteries is four guns in a row protected from the front by a concrete parapet of approximately 5 m (16 ft) thick with traversal walls between the gun positions. The batteries had no rear protection. Shelter for crew and ammunition cellars were built into and under the front parapet and the traversal walls. While the basic plan is similar, each battery is unique depending on the terrain. For the 10 inch guns the average distance between guns is 40 m (131 ft), but on smaller island such as Katajaluoto the guns are only 30 m (98 ft) apart while the larger Isosaari battery (No 1) has guns 50 m (164 ft) apart. Similarly the 6 inch batteries have guns 35 m (115 ft) apart on average, but in the very cramped Harmaja battery the distance between guns is only 20 m (66 ft) and the battery is not built on straight line but in a crooked L-shape. Many batteries have an icon
closet framed with granite.
, and protected the coastal routes on the western flank of the fortress. Miessaari naval front battery number 40 had four 6 in (152 mm) Canet guns, while Pyöräsaari had two two-gun batteries of light 57 mm guns. Pyöräsaari was connected to Miessaari by a bridge in 1917. The construction of the Canet gun battery began in spring 1915, the guns were installed in May 1916 and the construction was mostly finished by early 1917, though some work on the interior shelters continued until summer 1917. Pyöräsaari 57 mm gun positions were quarried in late autumn 1915 and completed in June 1916. The islands also formed the seam between naval and land fronts, and Miessaari had also a land-facing battery number 115 of six 6 in (152 mm) 190 pood model 1877 siege guns, supporting the base XXXIV in Haukilahti
-Westend area.
nniemi peninsula. Construction of the battery located in the middle of the island began shortly after the war broke up, in October 1914. The guns, transported from Vladivostok, were installed by January 1915 and the entire battery with ammunition cellars and concrete command tower was finished in spring 1916. The island had two searchlights, larger 200 cm and a smaller 150 cm one.
60°6′16.58"N 24°58′27.27"E is a small island with a lighthouse south of Suomenlinna between Katajaluoto and Kuivasaari. The island has been used as a pilot station and the current lighthouse was built in 1883. At the start of the war two 75 mm (3 in) guns were placed on the island. These were relocated in October 1914 when construction of a 6 inch Canet battery began. The small island did not have the necessary building materials, and sand, gravel and cement had to be brought in with barges. The guns were installed in February 1915 and the battery was finished in September 1916. Harmaja battery is the smallest of the long range batteries and the guns are not located in straight line but in an L-shaped formation. A breakwater surrounds the southern end of the island.
island 60°6′3.49"N 25°0′54.97"E is located west of Isosaari. Construction of a 6 inch Canet battery was planned in spring 1914, but the guns were located in Isosaari instead. After the war began construction of a 10 inch battery began on the western shore of the island. The guns, transported from Vladivostok, were placed on their foundations in February 1915 and the battery was finished in early winter of 1915. The main fire control station of the fortress with the only 6 m (20 ft) rangefinder was located in Kuivasaari. The island also had a 150 cm searchlight. Kuivasaari telephone exchange was also the central gunnery telephone exchange. A four-gun 75 mm anti-aircraft battery on wooden platforms was located on the northern part of the island.
was built on the island to transport supplies and ammunition.
60°8′44.18"N 25°3′1.96"E was the largest single island in Krepost Sveaborg, and is located south of Laajasalo
. Because of the size of the island Santahamina could be considered to belong to both main line of defence and the second line of defence. Santahamina was fortified during the Crimean War, and several gun batteries were built on the island during the decades between Crimean War and First World War. Most of the older guns, including eleven 6 inch 190 pood siege guns and thirteen 9 inch coastal mortars, were transported to the land front of the fortress shortly after the start of war. The remaining batteries were a 6 inch Canet battery, originally intended for Isosaari, at Itäniemi on the south-eastern part of the island and a 75 mm battery on the eastern shore. These batteries covered the sea east of Isosaari. Santahamina had a large garrison area and a substantial number of troops and supplies were located on the island.
island. The island was a summer house district and the land had to be expropriated from the owners. Resistance by the land owners delayed the process, and was still not fully complete by late 1916. Fortification works for an 11 inch battery began in April 1915, but the battery was changed to 10 inch guns in autumn of the same year. 10 inch battery is built on a rock hilltop at the centre of the island. In July 1915 construction of a smaller battery for 75 mm guns (originally planned for 57 mm guns) on the eastern tip of the island began.
is the only place of the main line of defence on the mainland. Construction of a 6 inch Canet battery began in late 1916. The battery fortifications, the parapet and traversal walls, were finished but the command points and most other auxiliary structures were not. The guns had arrived at the battery but were never installed and were reported stored nearby on the shore and pier in 1918.
was fortified during the Crimean War, but had been disarmed in 1895. During the First World War the only battery was a land front battery number 116 at Vaskiniemi, armed with four 9 in (229 mm) model 1867 guns in March 1915. This battery supported base XXXVII located in southern Espoo at Tapiola
—Otaniemi
area. The only naval front connection Lauttasaari had was an unfinished searchlight station in Länsiulapanniemi and bakery constructed between 1916 and 1917 near the land front battery that was also used to supply the coastal forts on the nearby islands. Lauttasaari was officially delegated to land front already in spring 1915.
is a group of islands south of Jätkäsaari
. In summer 1916 the 75 mm anti-aircraft battery on Melkki was relocated to Itäinen Pihlajasaari 60°8′23.03"N 24°55′20.02"E. The guns were on temporary wooden platforms, and the battery was relocated already in August as construction of new fortified concrete anti-aircraft positions and shelters began. The fortification work was completed but the guns were not installed before the war ended.
. In the years before First World War the island had three batteries with five 9 in (229 mm) model 1867 guns, four 6 inch 190 pood guns and two 57 mm quick fire guns. As the war began the 6 inch guns were relocated to the land front while the 9 inch guns were decommissioned and left in their positions. The two 57 mm guns and two more guns from Vallisaari were relocated to a new field fortified battery on the southern tip of the island. Additionally the island had 2-4 anti-aircraft guns of 75 mm or 3 in (76 mm) during the war. The island had also a 110 cm searchlight.
60°08′37"N 24°59′04"E. It included the islands of Kustaanmiekka, Susisaari, Iso Mustasaari, Pikku Mustasaari, Länsi-Mustasaari, Särkkä and the skerry
of Pormestarinluoto. Except for the smaller Särkkä and Pormestarinluoto the islands were connected by bridges or joined together. The islands housed the fortress commander and headquarters along with the main telephone exchange and the largest dry dock in Finland at the time. The citadel also had weapons and ammunition depots and other storage areas. Most of the fortification works were concentrated on other islands, and of the older armament only one battery of three 11 inch guns remained in active service in Kustaanmiekka island. To guard Kustaanmiekansalmi strait two batteries of 57 mm guns were built, one on Kustaanmiekka and one on Iso-Mustasaari island. A third battery of 57 mm guns on Länsi-Mustasaari guarded Särkänsalmi strait.
across Kukisalmi strait at the turn of the 19th and 20th centuries. From the late 19th century until the First World War Vallisaari was the most heavily fortified island of the fortress. Construction of a 6 inch Canet battery on the island began in 1912, but the guns were relocated to the outer islands on the new main line of defence at the beginning of the war. Of the older guns a five-gun battery of 11 inch model 1877 guns and six-gun battery of 11 inch mortars were still used during the war. Two of the mortars were transported to the land front in early 1915, and the rest were decommissioned and abandoned on their positions in 1916. A six-gun battery of 6 inch model 1877 siege guns on fortress carriages were transported to the land front by the end of 1914. Newer artillery included two 57 mm guns that were replaced with four 75 mm guns in October 1914. Of the Kuninkaansaari batteries one four-gun battery of 11 inch model 1877 guns was kept in service. Two of the five 11 inch mortars were also in use until 1915. The rest of the guns - five 9 inch model 1867 guns, four 6 inch model 1877 siege guns, two (possibly four) 9 inch mortars and three 11 inch mortars were moved to the land front shortly after the start of the war. Both Vallisaari and Kuninkaansaari had a 150 cm searchlight stations. Small Nuottasaari island 60°8′28.34"N 25°1′34.21"E north of Haminasalmi strait between Kuninkaansaari and Santahamina was armed with four 8 inch model 1867 guns in 1887, but the island had been disarmed by 1914.
ended Russia's participation in the First World War. The treaty affirmed the independence of Finland and required Russian troops to leave from the country. Of the approximately 35 000 Russian soldiers and sailors who were around Helsinki in January 1918 most were demobilized and sent home or simply left by 15 March. Around one thousand joined the Finnish Red Guards
in the Finnish Civil War. The Soviet leadership ordered Krepost Sveaborg headquarters to begin preparations to abandon the fortress and destroy what could not be evacuated in case it would fall in to German hands. Some field guns were transported to Russia, but all the coastal guns were left. On 3 April 1918 German Baltic Sea Division
landed in Hanko, after being requested by the White Senate of Vaasa
to participate in the Finnish Civil War against the Reds. Russian Baltic fleet officers had made an agreement with the Germans allowing a safe departure for the warships and disarming the fortress. Most of the Russian ships left by mid-April, but the last ships left only in May-June 1918. The disarmament - removing locks from the guns, cutting the cables controlling the mines and destroying the mine control stations - had to be done in secret as an agreement between Soviet government and Finnish Red Guards had promised the latter all the fortifications. When the Germans arrived in Helsinki the Red Guard could only use some of the land front fortifications in Leppävaara and Ruskeasuo, and the Germans with a well equipped and trained numerically superior force quickly captured Helsinki between 11th and 13 April. The Russian guards ceded the coastal forts to Germans according the their agreement. The disarmament of Krepost Sveaborg, denying the Reds from using it, was used in White propaganda
by how the engineer Allan Staffans had duped the Russians and removed the locks without authorization; but actually the disarmament occurred with the order of the fortress commander and with the knowledge of naval headquarters. On 12 May Krepost Sveaborg was renamed Suomenlinna to celebrate the new independency.
in 1971.
with regular ferry connection. The islands of Vallisaari and Kuninkaansaari are also currently being transferred to civilian authorities, with military tentatively scheduled to leave the islands by 2012. Pihlajasaaret is a Helsinki city recreation area open to public with regular ferry connection during summertime. Vasikkasaari and Lonna are also civilian areas open to visit, but more difficult to reach.
Russian Empire
The Russian Empire was a state that existed from 1721 until the Russian Revolution of 1917. It was the successor to the Tsardom of Russia and the predecessor of the Soviet Union...
land and sea fortress constructed around Helsinki
Helsinki
Helsinki is the capital and largest city in Finland. It is in the region of Uusimaa, located in southern Finland, on the shore of the Gulf of Finland, an arm of the Baltic Sea. The population of the city of Helsinki is , making it by far the most populous municipality in Finland. Helsinki is...
during First World War. The purpose of the fortress was to provide a secure naval base for the Russian Baltic fleet
Baltic Fleet
The Twice Red Banner Baltic Fleet - is the Russian Navy's presence in the Baltic Sea. In previous historical periods, it has been part of the navy of Imperial Russia and later the Soviet Union. The Fleet gained the 'Twice Red Banner' appellation during the Soviet period, indicating two awards of...
and to protect Helsinki and block routes to Saint Petersburg
Saint Petersburg
Saint Petersburg is a city and a federal subject of Russia located on the Neva River at the head of the Gulf of Finland on the Baltic Sea...
from a possible German
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
invasion. Krepost Sveaborg was part of the Peter the Great's Naval Fortress
Peter the Great's Naval Fortress
Peter the Great's naval fortress or the Tallinn-Porkkala defence station was a Russian fortification line, which aimed to block access to the Russian capital Saint Petersburg via the sea. The plans for the fortress included heavy coastal artillery pieces along the northern and southern shores of...
, a coastal fortification system protecting access to Saint Petersburg by sea. The central part of Krepost Sveaborg was the old fortress of Suomenlinna
Suomenlinna
Suomenlinna, until 1918 Viapori , or Sveaborg , is an inhabited sea fortress built on six islands , and which now forms part of the city of Helsinki, the capital of Finland.Suomenlinna is a UNESCO World Heritage site and popular with both tourists and locals, who...
where the fortress headquarters were located. Due to technological advances in artillery the old fortress was no longer capable of providing a sufficient protection, and a new main defensive line was built well beyond the old fortress boundaries. New coastal artillery
Coastal artillery
Coastal artillery is the branch of armed forces concerned with operating anti-ship artillery or fixed gun batteries in coastal fortifications....
guns built on outlying islands protected Krepost Sveaborg from the sea, while fortified lines constructed around Helsinki were intended to stop any attacks on land. The primary coastal guns were 10 in (254 mm) model 1891 guns and 6 in (152 mm) model 1892 Canet guns. Older 11 in (279 mm) model 1877 guns were also used. In summer 1917 the fortress had two hundred coastal or anti-landing guns, of which 24 were 10 inch guns in six batteries, 16 were 6 inch Canet guns in four batteries and twelve were 11 inch guns in three batteries. The artillery used in land fortifications included older coastal guns, old fixed carriage guns and newer light field guns. In March 1917, Krepost Sveaborg had a total of 463 guns, although many of them were obsolescent. Krepost Sveaborg was still partly incomplete in 1917 when the February Revolution
February Revolution
The February Revolution of 1917 was the first of two revolutions in Russia in 1917. Centered around the then capital Petrograd in March . Its immediate result was the abdication of Tsar Nicholas II, the end of the Romanov dynasty, and the end of the Russian Empire...
halted most of the construction work. Some further construction work was carried out during the remaining year, but all work halted during the October Revolution
October Revolution
The October Revolution , also known as the Great October Socialist Revolution , Red October, the October Uprising or the Bolshevik Revolution, was a political revolution and a part of the Russian Revolution of 1917...
. Following the Finnish Declaration of Independence, parts of the land fortifications were used in the Finnish Civil War
Finnish Civil War
The Finnish Civil War was a part of the national, political and social turmoil caused by World War I in Europe. The Civil War concerned control and leadership of The Grand Duchy of Finland as it achieved independence from Russia after the October Revolution in Petrograd...
. The coastal fortifications were later taken over by Finland to protect Helsinki, while the land fortifications were mostly abandoned and disarmed.
Background
SwedenSweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
had ceded Grand Duchy of Finland
Grand Duchy of Finland
The Grand Duchy of Finland was the predecessor state of modern Finland. It existed 1809–1917 as part of the Russian Empire and was ruled by the Russian czar as Grand Prince.- History :...
to Russian Empire
Russian Empire
The Russian Empire was a state that existed from 1721 until the Russian Revolution of 1917. It was the successor to the Tsardom of Russia and the predecessor of the Soviet Union...
as the result of the Finnish War
Finnish War
The Finnish War was fought between Sweden and the Russian Empire from February 1808 to September 1809. As a result of the war, the eastern third of Sweden was established as the autonomous Grand Duchy of Finland within the Russian Empire...
of 1808—1809 and along with it the fortress of Sveaborg, , the present day Suomenlinna. The fortress protected the southern Finland and became a naval base for the Russian Baltic Fleet. After the end of the Napoleonic Wars
Napoleonic Wars
The Napoleonic Wars were a series of wars declared against Napoleon's French Empire by opposing coalitions that ran from 1803 to 1815. As a continuation of the wars sparked by the French Revolution of 1789, they revolutionised European armies and played out on an unprecedented scale, mainly due to...
many new buildings were built to improve the living conditions on the fortress, but the fortifications were neglected. After the start of the Crimean War
Crimean War
The Crimean War was a conflict fought between the Russian Empire and an alliance of the French Empire, the British Empire, the Ottoman Empire, and the Kingdom of Sardinia. The war was part of a long-running contest between the major European powers for influence over territories of the declining...
in 1853 construction of new fortifications began on the other nearby islands and on the southern shore of Helsinki peninsula. In 1854 an Anglo-French naval fleet entered the Baltic Sea
Baltic Sea
The Baltic Sea is a brackish mediterranean sea located in Northern Europe, from 53°N to 66°N latitude and from 20°E to 26°E longitude. It is bounded by the Scandinavian Peninsula, the mainland of Europe, and the Danish islands. It drains into the Kattegat by way of the Øresund, the Great Belt and...
, hastening the work. These fortifications protected the flanks of the fortress and provided depth to the defence, but the problem of obsolescent artillery was not solved. Thus when the fleet attacked the fortress on the 6th of August 1855 they were able to bombard the fortress for two days from a distance of 4–5 km (2.5–3.1 mi) while the best Russian guns had a maximum range of 2500 m (8,202.1 ft).
After Crimean War fortifications of Viapori were improved by building artillery casemate
Casemate
A casemate, sometimes rendered casement, is a fortified gun emplacement or armored structure from which guns are fired. originally a vaulted chamber in a fortress.-Origin of the term:...
s and new bomb-proof buildings. Vallisaari just east of Suomenlinna was the site of the first new construction works. The harsh suppression of the Polish
Poland
Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...
January Uprising
January Uprising
The January Uprising was an uprising in the former Polish-Lithuanian Commonwealth against the Russian Empire...
of 1863 and the resulting criticism soured the relationships between Russia and western Europe and hastened the fortification works. Between 1863 and 1864 redoubt
Redoubt
A redoubt is a fort or fort system usually consisting of an enclosed defensive emplacement outside a larger fort, usually relying on earthworks, though others are constructed of stone or brick. It is meant to protect soldiers outside the main defensive line and can be a permanent structure or a...
s were built on Vallisaari, Kuninkaansaari and Santahamina islands. In 1860s and 1870s Russia purchased and then built under license new Prussia
Prussia
Prussia was a German kingdom and historic state originating out of the Duchy of Prussia and the Margraviate of Brandenburg. For centuries, the House of Hohenzollern ruled Prussia, successfully expanding its size by way of an unusually well-organized and effective army. Prussia shaped the history...
n Krupp
Krupp
The Krupp family , a prominent 400-year-old German dynasty from Essen, have become famous for their steel production and for their manufacture of ammunition and armaments. The family business, known as Friedrich Krupp AG Hoesch-Krupp, was the largest company in Europe at the beginning of the 20th...
rifled breech loading guns which were also used in Viapori. A total of 32 new bomb-proof stone powder cellars were built by the beginning of 1870s, further improving the defences. The Russo-Turkish War of 1877–1878 was the next crisis that threatened the peace between Russia and England, with new batteries being built at Viapori on Kuninkaansaari and older ones improved or rebuilt. New technology in the form of telegraph
Electrical telegraph
An electrical telegraph is a telegraph that uses electrical signals, usually conveyed via telecommunication lines or radio. The electromagnetic telegraph is a device for human-to-human transmission of coded text messages....
, railway lines and searchlight
Searchlight
A searchlight is an apparatus that combines a bright light source with some form of curved reflector or other optics to project a powerful beam of light of approximately parallel rays in a particular direction, usually constructed so that it can be swiveled about.-Military use:The Royal Navy used...
s began to be used. Improvements in artillery and ammunition forced improving the gun positions by covering the old walls and fortifications with a thick earthen walls. With high-explosive shells appearing at the end of the 19th century earth and stone were no longer sufficient and first concrete fortifications with steel doors were built in Viapori. Continually improving guns resulted increased range, necessitating rangefinder
Coincidence rangefinder
A coincidence rangefinder is a type of rangefinder that uses mechanical and optical principles to allow an operator to determine the distance to a visible object....
s, while heavier guns and ammunition required improving piers, roads, cranes and ammunition carts to transport the guns or move ammunition from magazines to guns. Despite the improvements the funds and resources allocated to the fortress were not sufficient to keep pace with the evolution of military technology. While parts of the fortress or were improved and new weapons or equipment were received, the overall condition of the fortress became ever more obsolescent, and the vulnerability of the flanks and rear were a lasting problem. By the end of 1880s and early 1890s Viapori could no longer be considered a proper fortress but only a coastal position, capable of defending only against an enemy coming directly from the sea. The primary role of the fortress became more one of internal politics, as it helped the Russians maintain control of Helsinki.
Krepost Sveaborg
In the 1890s the priority of the fortification works in the Baltic Sea had been the protection of the ice-free port of LiepājaLiepaja
Liepāja ; ), is a republican city in western Latvia, located on the Baltic Sea directly at 21°E. It is the largest city in the Kurzeme Region of Latvia, the third largest city in Latvia after Riga and Daugavpils and an important ice-free port...
, and the Kronstadt
Kronstadt
Kronstadt , also spelled Kronshtadt, Cronstadt |crown]]" and Stadt for "city"); is a municipal town in Kronshtadtsky District of the federal city of St. Petersburg, Russia, located on Kotlin Island, west of Saint Petersburg proper near the head of the Gulf of Finland. Population: It is also...
fortress protecting Saint Petersburg, relegating Viapori to a secondary status. After the losses during the Russo-Japanese War
Russo-Japanese War
The Russo-Japanese War was "the first great war of the 20th century." It grew out of rival imperial ambitions of the Russian Empire and Japanese Empire over Manchuria and Korea...
and in light of the rising might of the Imperial German Navy
Kaiserliche Marine
The Imperial German Navy was the German Navy created at the time of the formation of the German Empire. It existed between 1871 and 1919, growing out of the small Prussian Navy and Norddeutsche Bundesmarine, which primarily had the mission of coastal defense. Kaiser Wilhelm II greatly expanded...
, Liepāja was considered too vulnerable for a main fleet base, and the decision to build Peter the Great's Naval Fortress was made. In the new plans the main line of defence against the enemy was at the Porkkala
Porkkala
Porkkala is a peninsula in the Gulf of Finland located at Kirkkonummi in Southern Finland.The peninsula had great strategic value, as coastal artillery based there would be able to reach more than halfway across the Gulf of Finland...
-Tallinn
Tallinn
Tallinn is the capital and largest city of Estonia. It occupies an area of with a population of 414,940. It is situated on the northern coast of the country, on the banks of the Gulf of Finland, south of Helsinki, east of Stockholm and west of Saint Petersburg. Tallinn's Old Town is in the list...
line with Tallinn also the new main base for the Russian Baltic Fleet. Helsinki was to be a base for torpedo boat flotillas. The construction of the Tallinn naval base was delayed however, and with the new ships being constructed to replace the losses suffered against Japan the Russian Navy was forced to rely more on Helsinki despite the obsolete armament and inadequate fortifications at Viapori. As the threat of war in Europe grew, it became essential to expand the fortress to provide a necessary protection for the naval base. Until 1910, when the first 152 mm Canet guns arrived, the only modern weapons at Viapori were 57 mm quick fire guns
QF 6 pounder Nordenfelt
The QF 6 pounder Nordenfelt was a light 57 mm naval gun and coast defence gun of the late 19th century used by many countries.Note that this gun should not be confused with the short-barreled 57 mm Cockerill-Nordenfelt "Canon de caponnière" or fortification gun, which was used to arm the...
with the rest of the artillery designs dating from the Russo-Turkish War. The first new 254 mm guns arrived in 1913, but it was not until early 1914 that construction of the first new batteries began on Melkki and Isosaari. During the First World War the new Krepost Sveaborg was built to substantially expand the old fortress. A new main line of defence was constructed on the outlying islands, pushing the defensive line several kilometers southward, thus providing a secure outer anchorage south of the old fortress for larger warships without the need to navigate the narrow straits leading to the inner anchorage at Kruunuvuorenselkä. The older parts of the fortress became a second line of defence and the main storage areas. The rear of the fortress was finally protected by land fortifications, at first field fortifications on the Helsinki peninsula built in 1914, and, later, an outer line of fixed fortifications.
Troops and organization
At the start of the First World War Krepost Sveaborg was subordinated to the Russian 6th Army6th Army (Russian Empire)
The Russian Sixth Army was a World War I Russian field army that fought on the Eastern theatre of war.- Commanders :* 01.09.1912—26.08.1914 — General of Infantry Благовещенский, Александр Александрович...
. In summer 1916 Krepost Sveaborg was subordinated to Baltic Fleet. At the start of the war Krepost Sveaborg was divided into three defensive areas, with the sea front forming one defensive area and the land front divided to Pasila
Pasila
is a suburb in Helsinki, Finland. It is a central-northern neighbourhood, bordering Alppila to the south, Central Park to the west and Vallila to the east....
and Laajasalo
Laajasalo
Laajasalo is a group of islands that forms a neighbourhood in southern Helsinki, the capital of Finland. As of 2005, it had a population of 16,486....
-Herttoniemi
Herttoniemi
Herttoniemi is a neighbourhood and a suburb of Helsinki, the Finnish capital. It is located about 7 km east of the city centre and can be easily reached by metro in 10 minutes. It has an older northern suburb and a newer coastal suburb with ferry connections to the city centre...
areas. The sea front was further divided into six sectors, with sectors 1-4 at the old fortress, sector 5 at Melkki and sector 6 at Isosaari. The sea front was divided into main line of defence from Melkki to Isosaari and second line of defence from Lauttasaari
Lauttasaari
Lauttasaari is an island and neighbourhood of Western Helsinki , about 3 kilometres west of the city centre....
to Santahamina
Santahamina
Santahamina is an island and neighbourhood of Eastern Helsinki, Finland. At present it is a military base housing the Guard Jaeger Regiment, making access restricted...
at the end of 1914. As the new batteries were constructed Melkki was relegated to second line of defence and Lauttasaari to land front in spring 1915. At the land front new defensive lines were constructed from 1915 onward further away from the city center. The new land front was divided into three sectors: eastern, northern and western. Krepost Sveaborg was also responsible for a larger fortification district that included coast line west of the fortress until Hanko.
At the start of the war the fortification artillery units manning the fortress were organized into nine artillery companies and a machine gun detachment. In April 1915 the fortification artillery units were reorganized into a single fortification artillery regiment with three battalions and a machine gun company. Four companies manned the coastal forts at sea front. In June 1916 the regiment was divided in two, with 1st regiment responsible for the seaward defence and the 2nd for the landward defence. Both regiments had ten companies in three battalions. The 1st regiment was divided into three defence detachments, with south-western and south-eastern detachments responsible for the main line of defence on the outlying islands with the newest guns, while the third detachment manned the second line on the old fortress. The artillery regiments had a common supply unit responsible for the weapons, ammunition, transportation between islands etc. A signals company built and maintained the communication lines. The minefields
Naval mine
A naval mine is a self-contained explosive device placed in water to destroy surface ships or submarines. Unlike depth charges, mines are deposited and left to wait until they are triggered by the approach of, or contact with, an enemy vessel...
around the fortress were built by the Krepost Sveaborg mine company, from 1915 a mine battalion. In 1916 the fortress was reinforced by the mine battalion from Vladivostok
Vladivostok
The city is located in the southern extremity of Muravyov-Amursky Peninsula, which is about 30 km long and approximately 12 km wide.The highest point is Mount Kholodilnik, the height of which is 257 m...
fortress. Construction and engineering department of the fortress headquarters organized the construction works of the fortress with engineering and sapper units as well as the civilian workers.
Infantry units at the fortress manned the landward defences and provided detachments on the coastal forts for anti-landing and close defence duties. The peacetime Krepost Sveaborg fortress infantry regiment was reinforced by conscript units, which in 1915 were organized as the 427th and 428th infantry regiments to a new 107th infantry division which was sent to front line after a training period. In spring 1916 regiments from the new 116th division manned the fortress. At the autumn of 1916 units from different fortresses were brought to Krepost Sveaborg and organized into the 128th infantry division. In July 1917 the fortress was manned by the fortress infantry regiment and the 428th Lodeynoye Pole infantry regiment of the 128th division. In October 1917 the 128th was replaced by the 29th infantry division, badly mauled at the front and brought to Krepost Sveaborg for rest. At January-February 1918, when Finland gained its independence, Krepost Sveaborg had six infantry regiments: the 696th revolutionary regiment, the fortress infantry regiment and 113th, 114th, 115th and 116th regiments of the 29th infantry division.
Construction workers included Russian soldiers but also Finnish civilian workers and forced labour using prisoners transported from far east. Finns were exempt from conscription, and thus there was available manpower for fortification works. The payment for fortification works was slightly above average for manual labour, and made it an attractive option particularly for many rural workers. In 1915 when large scale construction of fortifications around Finland began Russians instituted a work responsibility for Finns based on wartime emergency law to obtain the necessary labour force. To ease the manpower shortage Russians brought convicted prisoners from far east to Finland in summer 1916 as forced labour. Approximately 2000-3000 men, including Chinese, Kyrgyz and Tatars, were employed as lumberjack
Lumberjack
A lumberjack is a worker in the logging industry who performs the initial harvesting and transport of trees for ultimate processing into forest products. The term usually refers to a bygone era when hand tools were used in harvesting trees principally from virgin forest...
s around Espoo and Sipoo
Sipoo
Sipoo is a municipality of Finland. Its seat is in Nikkilä/Nickby.It is the eastern neighbour of Helsinki and is located in the Uusimaa region. The municipality has a population of and covers an area of ofwhich is water...
. Kyrgyz were mainly guards. Asian workers were transported back to Russia already in 1917 however, citing the workers to be unaccustomed to the northern climate and possible threat of rebellion. The total number of workers in not known, but an estimated 10 000 to 15 000 men were used in construction works around Helsinki and up to 100 000 total in Finland. Complicated bureaucracy delayed the construction works, and the supervision of the works was also poor leading to a wide spread graft.
Coastal guns
The most powerful coastal guns used at Krepost Sveaborg were the 10 in (254 mm) 45 caliber model 1891 guns. They had a maximum range of 21 km (13 mi) but suffered from primitive mountings: the heavy guns, weighing 51 metric tons (56.2 ST), were completely hand-operated resulting in slow traverse and elevation rates and exhausting the gun crews. The rate of fire was only one shot every two minutes and they were also not capable of penetrating the armour of newer warships: at the range of 10 km (6.2 mi) they could penetrate 127 mm (5 in) of armour at 90° angle. First four guns were transported to the fortress in 1913 from Kronstadt fortress, two guns each from Constantin and Obrutshev forts. Twelve guns were transported from Vladivostok in 1914 and eight more arrived in 1915, with a total of 24 guns in six four-gun batteries. These guns formed the primary armament of the sea front main line of defence. The batteries were located on Rysäkari, Katajaluoto, KuivasaariKuivasaari
Kuivasaari is a Finnish island in the Gulf of Finland, near Helsinki. The island gets its name, meaning 'dry island', from the fact that there is no fresh water on the island, and water is instead pumped from the nearby Isosaari island.The whole island is a military installation and access for...
, Isosaari (two batteries) and Itä-Villinki.
The 6 in (152 mm) 45 caliber model 1892 guns supplemented the 10 inch guns of the sea front main line of defence. These guns were French
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
Canet guns
Canet guns
The Canet guns were a series of weapon systems developed by the French engineer Gustave Canet , who was design engineer for Schneider et Cie of Le Creusot.-320 mm naval guns:...
and had a maximum range of 13–14 km (8.1–8.7 mi). Unlike the 10 inch guns, the 6 inch guns had a modern counter-recoil system and achieved a rate of fire of five shots per minute. The six inch guns were intended against destroyer
Destroyer
In naval terminology, a destroyer is a fast and maneuverable yet long-endurance warship intended to escort larger vessels in a fleet, convoy or battle group and defend them against smaller, powerful, short-range attackers. Destroyers, originally called torpedo-boat destroyers in 1892, evolved from...
s and other smaller vessels. They were installed in four batteries of four guns each at the sea front on Miessaari, Harmaja
Harmaja
Harmaja is an island and a lighthouse outside Helsinki, south of the Suomenlinna sea fortress. The island has been functioning as a landmark since the 16th century. A landmark structure was built on the island in the 18th century and a light house in 1883. The first lighthouse was only 7.3 m high...
, Isosaari and Santahamina
Santahamina
Santahamina is an island and neighbourhood of Eastern Helsinki, Finland. At present it is a military base housing the Guard Jaeger Regiment, making access restricted...
. A fifth battery was under construction on the mainland at Skatanniemi cape. The guns for this battery arrived, bringing the total sea front number to twenty, but the construction was not completed before the war ended. Further seventeen guns on lower ship deck mountings with lower maximum elevation were used on the land front. The guns used at Krepost Sveaborg included both Russian Obukhov
Obukhov State Plant
Obukhov State Plant is a major Russian metallurgy and heavy machine-building plant in St. Petersburg, Russia. It was founded in 1863 to produce naval artillery based on German designs by Krupp. It has since been a major producer of artillery and other military equipment. From 1922 to 1992 it...
licence-produced guns and French Schneider guns.
The older heavy coastal artillery pieces, the 9 in (229 mm) and 11 in (279 mm) model 1867 and 1877 guns and the 9 in (229 mm) and 11 in (279 mm) model 1877 coastal mortars, were mostly transferred to land front or placed in reserve. Three batteries (twelve guns) of 11 inch model 1877 guns were used throughout the war at the sea front second line of defence at Kustaanmiekka, Kuninkaansaari and Vallisaari. At the start of the war 11 inch guns were also used at the main line of defence on Isosaari before 10 inch model 1891 guns replaced them. Two batteries of 11 inch coastal mortars remained in use until 1916 in Vallisaari and Kuninkaansaari. The mortars were also capable of firing to the rear of the fortress and were intended to keep the citizens of Helsinki loyal. The heavy shells of the mortars were considered to have a "suitable moral effect" on civilians. 6 in (152 mm) 22 caliber siege gun model 1877
6 inch siege gun M1877
6-inch siege gun model 1877 was a Russian 152.4 mm heavy siege gun. The gun was produced by Obukhov Steel Works in Saint Petersburg. It was utilized in Russo-Japanese War, World War I, Russian Civil War and some conflicts of the early 20th century where former parts of Russian empire were...
was primarily an army weapon used on wheeled carriage on land front, but some guns mounted on fortification mounts were also used on sea front at the start of the war.
Light coastal guns used at Krepost Sveaborg included 57 mm Nordenfelt
QF 6 pounder Nordenfelt
The QF 6 pounder Nordenfelt was a light 57 mm naval gun and coast defence gun of the late 19th century used by many countries.Note that this gun should not be confused with the short-barreled 57 mm Cockerill-Nordenfelt "Canon de caponnière" or fortification gun, which was used to arm the...
guns, fifteen guns at the beginning of the war and twenty by the end of the war. 75 mm (3 in) 50 caliber model 1892 Canet guns were similar to the six inch model 1892 gun. First of these guns arrived at 1914, and twelve coastal guns were used at Krepost Sveaborg, with an other eighth anti-aircraft gun versions with a 50° maximum elevation.
It was planned in 1916 to build four two-gun batteries of 12 in (305 mm) 52 caliber model 1907 guns at Krepost Sveaborg, but the work started in 1917 never progressed beyond building gun mount foundations and some ammunition and crew shelters. The batteries were to be built on the mainland, with guns in single open positions capable of firing on both land and sea targets. The batteries were located at Munkkiniemi
Munkkiniemi
Munkkiniemi is a neighbourhood in Helsinki. Subdivisions within the district are Vanha Munkkiniemi, Kuusisaari, Lehtisaari, Munkkivuori, Niemenmäki and Talinranta.The land in Munkkiniemi was from the 17th century a part of Munksnäs manor...
, Haaga
Haaga
Haaga is a district and a former municipality in the Western major district of Helsinki with a population of 25,435.Haaga is divided into four subareas, which are Pohjois-Haaga , Etelä-Haaga , Kivihaka and Lassila.Haaga has two railway stations: Huopalahti railway station in south and...
, Oulunkylä
Oulunkylä
Oulunkylä is a suburb and a neighbourhood of Helsinki, the capital of Finland. It is located north from the center of the city.It has been inhabited since the 13th century. Earlier an independent municipality, it was made part of Helsinki in 1946. A rink used for speed skating and bandy is...
and Koskela
Koskela
Koskela , Forsby is a district in the city of Helsinki, Finland.-Politics:Results of the Finnish parliamentary election, 2011 in Koskela:*Social Democratic Party 24.2%*True Finns 16.8%*Left Alliance 16.0%...
. The 305 mm guns were used later to protect Helsinki however, as Finland built an armoured twin turret on Kuivasaari between 1931 and 1935 and two guns in open positions at Isosaari during the Second World War in 1941-1944.
| Gun | ||||
|---|---|---|---|---|
| 10 inch 45 caliber model 1891 | 0 | 16 | 16 | 24 |
| 11 inch model 1877 | 10 | 19 | 20 | 12 |
| 6 inch 45 caliber model 1892 Canet | 12 | 12 | 12 | 16+4 |
| 6 in (152 mm) 22 caliber siege gun model 1877 6 inch siege gun M1877 6-inch siege gun model 1877 was a Russian 152.4 mm heavy siege gun. The gun was produced by Obukhov Steel Works in Saint Petersburg. It was utilized in Russo-Japanese War, World War I, Russian Civil War and some conflicts of the early 20th century where former parts of Russian empire were... |
29 | 2 | 0 | 0 |
| 75 mm 50 caliber model 1892 Canet | 0 | 14 | 20 | 12 |
| 57 mm 48 caliber Nordenfelt QF 6 pounder Nordenfelt The QF 6 pounder Nordenfelt was a light 57 mm naval gun and coast defence gun of the late 19th century used by many countries.Note that this gun should not be confused with the short-barreled 57 mm Cockerill-Nordenfelt "Canon de caponnière" or fortification gun, which was used to arm the... |
2 | 15 | 15 | 20 |
| 11 inch model 1877 mortar | 9 | 8 | 4 | 0 |
Field guns
Field guns were used on both the land front and as anti-landing and close defence weapons on the coastal forts. Gun models included both older fixed carriage guns and more modern weapons with counter-recoil systems. The most common models were the 6 inch siege gun model 1877 with a 190 poodPood
Pood , is a unit of mass equal to 40 funt . It is approximately 16.38 kilograms . It was used in Russia, Belarus and Ukraine. Pood was first mentioned in a number of documents of the 12th century....
version used on both field and fortress mounts and a lighter 120 pood barrel version on field carriage. 42 line
Line (length)
The line is a unit of measurement, one line being equal to of an English inch. It was defined as one-quarter of a barleycorn, which defined the inch even before 1066. The French ligne was simarly defined as of the pouce...
(107 mm (4.2 in)) battery gun model 1877 and 34 line (87 mm (3.4 in)) light field gun model 1877
87 mm light field gun M1877
87-mm light field gun M1877 was a field gun utilized in Russo-Japanese War, World War I, Russian Civil War and a number of interwar period armed conflicts with participants from the former Russian Empire. The gun was initially developed by Krupp, but was also produced in the Russian Empire...
were other older field artillery pieces used at the fortress. 76 mm model 1902 gun was a newer rapid fire field gun with a counter recoil system. The 76 mm model 1902 gun was also used as an anti-aircraft gun on a modified "Rosenberg" mount. The land front weaponry also included a variety of smaller caliber anti-storming guns, caponier guns and other mixed artillery pieces. The reserve guns included different older models up to bronze-barrelled mortars.
Mines
Naval mineNaval mine
A naval mine is a self-contained explosive device placed in water to destroy surface ships or submarines. Unlike depth charges, mines are deposited and left to wait until they are triggered by the approach of, or contact with, an enemy vessel...
s were also used to protect Krepost Sveaborg from an attack from the sea. An outer line of contact mines was laid approximately 15 km (9 mi) outside the main line of defence. Shore detonated controlled mines
Controlled mines
A Controlled Mine was a circuit fired weapon used in coastal defenses with ancestry going back to 1805 when Robert Fulton termed his underwater explosive device a torpedo:...
were used to create an inner mine barrier to protect the entrances to the outer anchorage. These mines were laid typically in three rows with 200 m (656 ft) separation between rows and 60 m (197 ft) between mines in a row. Controlled mines required an extensive cabling system to the shore stations where the command to detonate the mines was given. Fortified electrical stations provided the necessary electricity for the mine control network. Electricity was also used for communication systems, searchlights, electrical ammunition lifts and in barracks and crew shelters.
Rangefinders
Vertical based rangefindersDepression position finder
A depression position finder is an observation instrument that was used in the fire control system of the U.S. Coast Artillery to locate targets in range and/or azimuth as part of the process of directing the fire of a battery of coast defense guns or mortars...
, where the known base length is the height of the rangefinder
Rangefinder
A rangefinder is a device that measures distance from the observer to a target, for the purposes of surveying, determining focus in photography, or accurately aiming a weapon. Some devices use active methods to measure ; others measure distance using trigonometry...
from sea level, were first used at Viapori in the 1880s. Vertical based rangefinders required only one instrument, but they were susceptible to interference from vibration caused by firing of the guns. Vertical based rangefinders also required a substantially high measurement site that was a problem on the low islands. To measure distance with reasonable accuracy to a target 10 km (6 mi) away the rangefinder had to be at least 10 fathom
Fathom
A fathom is a unit of length in the imperial and the U.S. customary systems, used especially for measuring the depth of water.There are 2 yards in an imperial or U.S. fathom...
s (21.3 m (70 ft)) and preferably 20 fathoms (42.6 m (140 ft)) high - often impossible to achieve. Measurement sites had usually the rangefinder on a stone or masonry column 110 cm (43 in) high lying on a granite foundation. The measurement pavilions had simple wooden walls and sheet metal roof protecting them from the elements and were 4–6 m² (43.1–64.6 sqft) in size. Vertical rangefinders were no longer used on the new forts built on the outer islands.
Distance measurement at the 10 in (254 mm) model 1891 batteries was based on horizontal triangulation
Triangulation
In trigonometry and geometry, triangulation is the process of determining the location of a point by measuring angles to it from known points at either end of a fixed baseline, rather than measuring distances to the point directly...
from two different points, a primary and secondary, on separate islands. The rangefinders used were general von der Launitz's models 1903 and 1905-07. The average distance between the two points at Krepost Sveaborg was 5.5 km (3 mi). Target information was sent from the primary point to the battery command point. If the primary point was located away from the battery or directing a different battery a rangefinder converter designed by colonel Kovanko was used to calculate the firing solution. A weakness in using two measurement points was that any malfunctions in either of the rangefinders or in the telephone system would render the system inoperable. Target indication between the primary and secondary points could also pose problems, as there would often be several similar target ships. The system was also not capable of measuring distances to targets in the rear of the battery; a maximum measurement sector was 140°.
On the smaller 6 in (152 mm) model 1892 Canet gun and anti-aircraft batteries 3 m (10 ft) wide Zeiss stereoscopic rangefinders
Coincidence rangefinder
A coincidence rangefinder is a type of rangefinder that uses mechanical and optical principles to allow an operator to determine the distance to a visible object....
were used. Maximum distance that could be reliably measured with three meter rangefinders was 8–10 km (5–6.2 mi), while the maximum range of the six inch guns was 13–14 km (8.1–8.7 mi). A single 6 m (20 ft) rangefinder was used by the commander of the artillery in a central fire control station at Kuivasaari. Six meter rangefinders were also planned for the 10 inch batteries later in the war but never obtained.
Searchlights
Searchlights were first used at Viapori during the Russo-Turkish War in 1878, and they were originally intended for guarding the controlled mine barriers. During the First World War fortified searchlight positions were part of the coastal forts. The main line of defence had larger two 200 cm (79 in) searchlights at Rysäkari and Kuivasaari and an additional six smaller 150 cm (59 in) searchlights beside them and on the other islands. Miessaari 150 cm seachlight position was not completed during the war. In the second line 150 cm searchlights were used on Kuninkaansaari and Vallisaari, while other forts had 110 cm (43 in) or 90 cm (35 in) searchlights. Diesel generatorDiesel generator
A diesel generator is the combination of a diesel engine with an electrical generator to generate electrical energy....
s provided the necessary electrical power to operate the searchlights. Searchlights were used in disappearing positions, where the searchlight was normally in a shelter and only exposed when needed for illumination. The disappearing positions had two types: either the searchlight was raised from the shelter by a lifting mechanism, or it was moved by rails from the shelter to position.
Communications
Telephone and telegraph system linked the various parts of the fortress. Krepost Sveaborg had both a regular telephone system and a second, independent telephone network dedicated for fire control. The primary telephone exchange was located on Iso Mustasaari. The various island forts had their own telephone exchanges, while Kuivasaari and Isosaari had central coastal telephone exchanges with links to other main line of defence forts. The telephone cabels on main line of defence were usually buried, while second line used overhead lines. Besides telephone optical telegraphs, signal lampSignal lamp
A signal lamp is a visual signaling device for optical communication . Modern signal lamps are a focused lamp which can produce a pulse of light...
s and signal flags were also used.
Land front
To protect Krepost Sveaborg and the naval base in particular from a German attack from land the fortifications were built to protect the fortress. The first fortifications were hastily built in 1914 to block access to the Helsinki peninsula and to guard the eastern flank of LaajasaloLaajasalo
Laajasalo is a group of islands that forms a neighbourhood in southern Helsinki, the capital of Finland. As of 2005, it had a population of 16,486....
and Santahamina
Santahamina
Santahamina is an island and neighbourhood of Eastern Helsinki, Finland. At present it is a military base housing the Guard Jaeger Regiment, making access restricted...
by a scarce line of fortifications at Ruskeasuo
Ruskeasuo
Ruskeasuo is a neighbourhood of Helsinki , about 3 kilometres north of the city centre....
-Pasila
Pasila
is a suburb in Helsinki, Finland. It is a central-northern neighbourhood, bordering Alppila to the south, Central Park to the west and Vallila to the east....
-Käpylä
Käpylä
Käpylä is a neighbourhood of Helsinki with 7,600 inhabitants. Administratively speaking, Käpylä is a part of the Vanhakaupunki district.It is located between Kumpula, Oulunkylä and Koskela...
-Koskela
Koskela
Koskela , Forsby is a district in the city of Helsinki, Finland.-Politics:Results of the Finnish parliamentary election, 2011 in Koskela:*Social Democratic Party 24.2%*True Finns 16.8%*Left Alliance 16.0%...
-Viikki
Viikki
Viikki is a neighbourhood of about 5,500 inhabitants in Helsinki, Finland. It is located at the bottom of Vanhankaupunginlahti bay, some 7–10 km from the city centre....
-Herttoniemi
Herttoniemi
Herttoniemi is a neighbourhood and a suburb of Helsinki, the Finnish capital. It is located about 7 km east of the city centre and can be easily reached by metro in 10 minutes. It has an older northern suburb and a newer coastal suburb with ferry connections to the city centre...
-Roihuvuori
Roihuvuori
Roihuvuori is a quarter, part of Herttoniemi neighbourhood in Helsinki, Finland. The population of Roihuvuori is approximately 8,000 and its area is 1.47 km². There is a church, two schools, shops and restaurants in Roihuvuori...
. Lauttasaari
Lauttasaari
Lauttasaari is an island and neighbourhood of Western Helsinki , about 3 kilometres west of the city centre....
, Meilahti
Meilahti
Meilahti is a neighbourhood of Helsinki between Mannerheimintie and a bay named Seurasaarenselkä. Most of the houses in Meilahti were built in the 1930s and 1940s. Meilahti is home to over 6700 people including the President of Finland Tarja Halonen who lives on the shore in the President's...
and Laajasalo were also fortified to some extent. It was also planned to fortify Kulosaari
Kulosaari
Kulosaari is an island and a suburb in Helsinki, Finland. It is also the 42nd neighbourhood of the city. Construction of villas on the island started in the beginning of the 20th century, and a bridge from Sörnäinen was opened in 1919...
and Vartiosaari
Vartiosaari
Vartiosaari , Vårdö is a subdistrict of Helsinki, Finland....
. These first fortifications were field fortifications located 6–7 km (3.7–4.3 mi) from the city center, with the defence concentrated at fortified hilltop redoubt
Redoubt
A redoubt is a fort or fort system usually consisting of an enclosed defensive emplacement outside a larger fort, usually relying on earthworks, though others are constructed of stone or brick. It is meant to protect soldiers outside the main defensive line and can be a permanent structure or a...
s.
In early 1915 it was decided to build new defenses further away from the city center. The new defenses were stronger fixed fortifications with positions quarried into rock or dug into ground. Fortifications were built from wood and stone masonry as well as concrete. New fortifications had a network of defensive structures, with trenches, rifle pits, machine gun nests, barbed wire obstacles
Wire obstacle
In the military science of fortification, wire obstacles are defensive obstacles made from barbed wire, barbed tape or concertina wire. They are designed to disrupt, delay and generally slow down an attacking enemy...
, shelters and roads. Artillery batteries were located 0.5–1.5 km (0.310686368324903–0.93205910497471 mi) behind the front line, often located on reverse slope. Artillery batteries had 2-6, typically four, guns. Heavily fortified caponiers providing flanking fire were built on places of the front line. First a northern line was built at Leppävaara
Leppävaara
Leppävaara or Alberga is a district of Espoo, a city in Finland. A major traffic hub in the Greater Helsinki region, the Rantarata rail line and Kehä I, the busiest road in Finland, cross in Leppävaara. The Sello Shopping Centre is also located there...
-Kaarela
Kaarela
Kaarela is a subdistrict in a Western major district of Helsinki, Finland.Kaarela is split into four subareas: Kannelmäki , Maununneva , Malminkartano and Hakuninmaa and has a total population of 26,414- References :...
-Pakila
Pakila
Pakila is a neighbourhood in Northern Helsinki. It comprises Länsi-Pakila and Itä-Pakila. Pakila has approximately 9,829 inhabitants which of 6464 lives in Länsi-Pakila and 3365 in Itä-Pakila...
-Pukinmäki
Pukinmäki
Pukinmäki is a district on the northeastern part of Helsinki, Finland.It has a population of 8,450 .Pukinmäki is located next to Ring I.Pukinmäki railway station is located in Pukinmäki....
-Myllypuro
Myllypuro
Myllypuro , Kvarnbäcken is an eastern neighborhood of Helsinki, Finland....
-Vartiokylä
Vartiokylä
Vartiokylä is a neighbourhood in eastern Helsinki, the capital of Finland. Its name is derived from the ruins of an eleventh century fortress on the Linnanvuori hill in Vartioharju, one of Vartiokylä's subdivisions. The working population of Helsinki started building their houses in the area after...
. Construction on a western line from Leppävaara to Westend via Tapiola
Tapiola
Tapiola or Hagalund is a district of Espoo on the south coast of Finland, and is one of the major urban centres of Espoo...
began shortly afterwards. In late 1915 it was decided to build an outer line of defence on the northern and eastern sectors, extending the fortifications northward and in the east from Pukinmäki to Malmi
Malmi
Malmi has several meanings.*Malmi is the Finnish language word for ore.*Malmi is a district in the city of Helsinki.*Malmi is a village in the municipality of Siuntio.*Malmi is a village in the municipality of Pyhtää....
, Mellunkylä
Mellunkylä
Mellunkylä is a neighbourhood in East Helsinki, Finland.The area of Mellunkylä is 9,9 km2 and it has population of 36,360 .There are five suburbs in Mellunkylä:*Kontula *Vesala *Mellunmäki *Kivikko...
and Vuosaari
Vuosaari
Vuosaari is a neighbourhood in the City of Helsinki, Finland. It is located by the sea in East Helsinki, and with its area of 15.38 km² is geographically the largest district in the city. It also has two Helsinki Metro stations, Rastila and Vuosaari...
. Fortification works continued until the February revolution of 1917, and some work was done until early 1918. The land front was divided into three sectors, eastern, northern and western with 36 bases, numbered I-XXXVII. The bases were usually centered on hilltops with the strongest defences.
The basic front line fortifications were open or covered machine gun nests, rifle pits, observation posts and shelters. Most of the structures were designed to be covered with a concrete roof poured on wooden planks occasionally reinforced with railway tracks. Some of the positions were built with stone or logs. Many of the fortifications have been left uncovered however, built only to a point where adding the missing roof could be accomplished quickly. The basic fortified types are a type A square machine gun nest, type B square rifle or machine gun pit, type C rounded rifle or observation pit, type D oval rifle pit with several firing ports and types E and F large rifle positions for multiple shooters. There is considerable variation between individual structures among the basic types, with newer positions generally built larger and stronger.
Naval front
Coastal fortifications on the naval front protected Krepost Sveaborg from an attack from the sea. During the war new fortifications were built on the outlying islands pushing the defences outward to protect the ships in the harbour from new modern guns. During the First World War the naval front of the fortress was modernized almost completely. The new gun batteries can be divided into four types: heavy long range batteries, close range batteries, anti-landing batteries equipped with field guns and anti-aircraft batteries which appeared during the war for the first time. The naval front was divided into six sectors at the start of the war with sectors 1-4 comprising the old fortress, sector 5 Isosaari and sector 6 Melkki. The central fire control post was located in Vallisaari. As the new coastal forts were completed the organization changed and the naval front was divided into two parts: an outer main line of defence from Melkki to Isosaari and an inner second line of defence from Lauttasaari to Santahamina. The naval front command post was located in Vallisaari and the main artillery command post in Kuivasaari.The long range batteries of 10 in (254 mm) and 6 in (152 mm) guns included ten batteries with six 10 inch batteries and four 6 inch batteries, with one more under construction. The basic shape of the batteries is four guns in a row protected from the front by a concrete parapet of approximately 5 m (16 ft) thick with traversal walls between the gun positions. The batteries had no rear protection. Shelter for crew and ammunition cellars were built into and under the front parapet and the traversal walls. While the basic plan is similar, each battery is unique depending on the terrain. For the 10 inch guns the average distance between guns is 40 m (131 ft), but on smaller island such as Katajaluoto the guns are only 30 m (98 ft) apart while the larger Isosaari battery (No 1) has guns 50 m (164 ft) apart. Similarly the 6 inch batteries have guns 35 m (115 ft) apart on average, but in the very cramped Harmaja battery the distance between guns is only 20 m (66 ft) and the battery is not built on straight line but in a crooked L-shape. Many batteries have an icon
Icon
An icon is a religious work of art, most commonly a painting, from Eastern Christianity and in certain Eastern Catholic churches...
closet framed with granite.
Main line of defence
The main line of defence was the outer seaward defence of Krepost Sveaborg. The main line of defence had the newest fortifications and the heaviest and most modern armament. At the end of the war it was compromised of (from west to east): Miessaari and Pyöräsaari, Rysäkari, katajaluoto, Harmaja, Kuivasaari, Isosaari, Santahamina and Itä-Villinki islands and Skatanniemi cape. The living conditions on the small, exposed islands were often poor, and the food supply was arranged from the older parts of the fortification with a week's supply of canned food, sugar and other compact food products stored on the islands. Construction of bakeries on the outer forts began after the February revolution as a result of the demand of an Artillery regiment committee formed by the soldiers.Miessaari and Pyöräsaari
Miessaari 60°7′55.88"N 24°46′50.49"E and the small Pyöräsaari 60°7′40.18"N 24°46′11.56"E formed the western reach of the naval front main line of defence. They are located near the coast of EspooEspoo
Espoo is the second largest city and municipality in Finland. The population of the city of Espoo is . It is part of the Helsinki Metropolitan Area along with the cities of Helsinki, Vantaa, and Kauniainen. Espoo shares its eastern border with Helsinki and Vantaa, while enclosing Kauniainen....
, and protected the coastal routes on the western flank of the fortress. Miessaari naval front battery number 40 had four 6 in (152 mm) Canet guns, while Pyöräsaari had two two-gun batteries of light 57 mm guns. Pyöräsaari was connected to Miessaari by a bridge in 1917. The construction of the Canet gun battery began in spring 1915, the guns were installed in May 1916 and the construction was mostly finished by early 1917, though some work on the interior shelters continued until summer 1917. Pyöräsaari 57 mm gun positions were quarried in late autumn 1915 and completed in June 1916. The islands also formed the seam between naval and land fronts, and Miessaari had also a land-facing battery number 115 of six 6 in (152 mm) 190 pood model 1877 siege guns, supporting the base XXXIV in Haukilahti
Haukilahti
Haukilahti or Gäddvik is a mainly residential district in the city of Espoo, Finland.Haukilahti is situated immediately west of the more commercially attractive district of Westend, which itself borders the Gulf of Finland to the east, beyond which lies the neighbouring city of Helsinki, the...
-Westend area.
Rysäkari
Rysäkari island 60°6′3.95"N 24°49′55.27"E had the westernmost 10 inch battery, and could command the western sea routes up to south-western shores of PorkkalaPorkkala
Porkkala is a peninsula in the Gulf of Finland located at Kirkkonummi in Southern Finland.The peninsula had great strategic value, as coastal artillery based there would be able to reach more than halfway across the Gulf of Finland...
nniemi peninsula. Construction of the battery located in the middle of the island began shortly after the war broke up, in October 1914. The guns, transported from Vladivostok, were installed by January 1915 and the entire battery with ammunition cellars and concrete command tower was finished in spring 1916. The island had two searchlights, larger 200 cm and a smaller 150 cm one.
Katajaluoto
Katajaluoto island 60°6′0.57"N 24°54′54.68"E is a narrow, north-south oriented island located approximately half way on the line between Rysäkari and Harmaja. A 10 inch battery built on the widest part divides the island into northern and southern parts. The construction of the battery began in October 1914 and the guns were placed on their foundations in early 1915 with the parapet and traversal walls completed in autumn 1915. Katajaluoto battery is the narrowest of the 10 inch batteries. The northern shore of the island has a heavily fortified concrete bunker used as mine control bunker, telephone exchange and electrical station. The island had a 150 cm searchlight. There is also a unique fortified concrete latrine on the eastern shore.Harmaja
HarmajaHarmaja
Harmaja is an island and a lighthouse outside Helsinki, south of the Suomenlinna sea fortress. The island has been functioning as a landmark since the 16th century. A landmark structure was built on the island in the 18th century and a light house in 1883. The first lighthouse was only 7.3 m high...
60°6′16.58"N 24°58′27.27"E is a small island with a lighthouse south of Suomenlinna between Katajaluoto and Kuivasaari. The island has been used as a pilot station and the current lighthouse was built in 1883. At the start of the war two 75 mm (3 in) guns were placed on the island. These were relocated in October 1914 when construction of a 6 inch Canet battery began. The small island did not have the necessary building materials, and sand, gravel and cement had to be brought in with barges. The guns were installed in February 1915 and the battery was finished in September 1916. Harmaja battery is the smallest of the long range batteries and the guns are not located in straight line but in an L-shaped formation. A breakwater surrounds the southern end of the island.
Kuivasaari
KuivasaariKuivasaari
Kuivasaari is a Finnish island in the Gulf of Finland, near Helsinki. The island gets its name, meaning 'dry island', from the fact that there is no fresh water on the island, and water is instead pumped from the nearby Isosaari island.The whole island is a military installation and access for...
island 60°6′3.49"N 25°0′54.97"E is located west of Isosaari. Construction of a 6 inch Canet battery was planned in spring 1914, but the guns were located in Isosaari instead. After the war began construction of a 10 inch battery began on the western shore of the island. The guns, transported from Vladivostok, were placed on their foundations in February 1915 and the battery was finished in early winter of 1915. The main fire control station of the fortress with the only 6 m (20 ft) rangefinder was located in Kuivasaari. The island also had a 150 cm searchlight. Kuivasaari telephone exchange was also the central gunnery telephone exchange. A four-gun 75 mm anti-aircraft battery on wooden platforms was located on the northern part of the island.
Isosaari
Isosaari 60°6′7.19"N 25°3′8.76"E is the largest of the outlying islands. The island's central location and size made it the most heavily armed coastal fort and it was part of the plans for expanding Krepost Sveaborg already in 1909. In May 1914 construction of four concrete fortified batteries began: one 10 inch battery, one 11 inch battery and two 6 inch batteries. The start of the war hastened the consctruction works that had progressed slowly, and three 10 inch guns were placed on temporary wooden platforms. The concrete batteries were finished by autumn 1915, but a change in plans resulted in the second 6 inch battery being located in Santahamina instead. In January 1916 work began to modify the 11 inch battery (battery number 2) for 10 inch guns, with the modifications complete in 1916. The first 10 inch battery is located on the south-western tip of the island, while the other two batteries are on the south-eastern shore. A 150 cm searchlight was located near the first 10 inch battery and a 200 cm searchlight near the two other batteries. A narrow gauge military railwayTrench railways
Trench Railways represented military adaptation of early 20th century railway technology to the problem of keeping soldiers supplied during the static trench warfare phase of World War I...
was built on the island to transport supplies and ammunition.
Santahamina
SantahaminaSantahamina
Santahamina is an island and neighbourhood of Eastern Helsinki, Finland. At present it is a military base housing the Guard Jaeger Regiment, making access restricted...
60°8′44.18"N 25°3′1.96"E was the largest single island in Krepost Sveaborg, and is located south of Laajasalo
Laajasalo
Laajasalo is a group of islands that forms a neighbourhood in southern Helsinki, the capital of Finland. As of 2005, it had a population of 16,486....
. Because of the size of the island Santahamina could be considered to belong to both main line of defence and the second line of defence. Santahamina was fortified during the Crimean War, and several gun batteries were built on the island during the decades between Crimean War and First World War. Most of the older guns, including eleven 6 inch 190 pood siege guns and thirteen 9 inch coastal mortars, were transported to the land front of the fortress shortly after the start of war. The remaining batteries were a 6 inch Canet battery, originally intended for Isosaari, at Itäniemi on the south-eastern part of the island and a 75 mm battery on the eastern shore. These batteries covered the sea east of Isosaari. Santahamina had a large garrison area and a substantial number of troops and supplies were located on the island.
Itä-Villinki
Itä-Villinki 60°9′28.63"N 25°8′15.9"E is located just east of the larger VillinkiVillinki
Villinki is an island and a subdistrict of Helsinki, Finland....
island. The island was a summer house district and the land had to be expropriated from the owners. Resistance by the land owners delayed the process, and was still not fully complete by late 1916. Fortification works for an 11 inch battery began in April 1915, but the battery was changed to 10 inch guns in autumn of the same year. 10 inch battery is built on a rock hilltop at the centre of the island. In July 1915 construction of a smaller battery for 75 mm guns (originally planned for 57 mm guns) on the eastern tip of the island began.
Skatanniemi
Skatanniemi peninsula 60°11′34.81"N 25°10′40.46"E in UutelaUutela
Uutela is a nature park in Vuosaari, Helsinki, Finland. It is situated by the sea, and attracts visitors from all over the Helsinki capital area.-External links:*...
is the only place of the main line of defence on the mainland. Construction of a 6 inch Canet battery began in late 1916. The battery fortifications, the parapet and traversal walls, were finished but the command points and most other auxiliary structures were not. The guns had arrived at the battery but were never installed and were reported stored nearby on the shore and pier in 1918.
Second line of defence
The second line of defence included the older parts of the fortress and contained most of the storage and supply areas and other rear line functions. The fighting power of the second line was limited to quick-firing 75 mm and 57 mm guns and old 11 inch cannons and mortars. The primary combat objective of the batteries on the second line was to prevent enemy ships from passing through Kustaanmiekansalmi or Särkänsalmi straits to the inner anchorage on Kruunuvuorenselkä. The second line included Lauttasaari, Melkki, Pihlajasaaret, Harakka, the central citadel at Suomenlinna, Lonna, Vallisaari, Kuninkaansaari, Nuottasaari and Vasikkasaari.Lauttasaari
LauttasaariLauttasaari
Lauttasaari is an island and neighbourhood of Western Helsinki , about 3 kilometres west of the city centre....
was fortified during the Crimean War, but had been disarmed in 1895. During the First World War the only battery was a land front battery number 116 at Vaskiniemi, armed with four 9 in (229 mm) model 1867 guns in March 1915. This battery supported base XXXVII located in southern Espoo at Tapiola
Tapiola
Tapiola or Hagalund is a district of Espoo on the south coast of Finland, and is one of the major urban centres of Espoo...
—Otaniemi
Otaniemi
Otaniemi , or Otnäs , is a district of Espoo, Finland. It is located near the border of Helsinki, the capital of Finland....
area. The only naval front connection Lauttasaari had was an unfinished searchlight station in Länsiulapanniemi and bakery constructed between 1916 and 1917 near the land front battery that was also used to supply the coastal forts on the nearby islands. Lauttasaari was officially delegated to land front already in spring 1915.
Melkki
Melkki 60°7′54.65"N 24°53′17.97"E is located south of Lauttasaari. Construction of a 6 inch Canet battery and 11 inch model 1877 battery began in May 1914, but the work was halted after the war began. The Canet battery was relocated to Harmaja, and the 11 inch guns were used only for a short period on temporary wooden platforms. A 75 mm anti-aircraft battery was located on the island in October 1914. In summer 1916 the guns were removed and the island was turned over for use as part of the naval base harbour facilities with machine shops and a naval mine depot.Pihlajasaaret
PihlajasaaretPihlajasaari
Pihlajasaari is an island in Helsinki, the capital of Finland.Pihlajasaari actually consists of two separate islands connected with a bridge...
is a group of islands south of Jätkäsaari
Jätkäsaari
Jätkäsaari is a quarter in Helsinki, the capital city of Finland. It is part to the Kampinmalmi district and Länsisatama neighbourhood. It is was the location of the main container harbour in Helsinki until late 2008, when the harbour moved to the new facilities in Vuosaari...
. In summer 1916 the 75 mm anti-aircraft battery on Melkki was relocated to Itäinen Pihlajasaari 60°8′23.03"N 24°55′20.02"E. The guns were on temporary wooden platforms, and the battery was relocated already in August as construction of new fortified concrete anti-aircraft positions and shelters began. The fortification work was completed but the guns were not installed before the war ended.
Harakka
Harakka 60°9′1.41"N 24°57′27.32"E is located near the coast of Helsinki, south of KaivopuistoKaivopuisto
Kaivopuisto , or in spoken language, Kaivari, is one of the oldest and best known parks in central Helsinki, Finland, and also a neighbourhood of about 500 inhabitants where the park is located.-Geography:...
. In the years before First World War the island had three batteries with five 9 in (229 mm) model 1867 guns, four 6 inch 190 pood guns and two 57 mm quick fire guns. As the war began the 6 inch guns were relocated to the land front while the 9 inch guns were decommissioned and left in their positions. The two 57 mm guns and two more guns from Vallisaari were relocated to a new field fortified battery on the southern tip of the island. Additionally the island had 2-4 anti-aircraft guns of 75 mm or 3 in (76 mm) during the war. The island had also a 110 cm searchlight.
The central citadel
The central citadel of Krepost Sveaborg was formed on the old Swedish fortress of Sveaborg, modern SuomenlinnaSuomenlinna
Suomenlinna, until 1918 Viapori , or Sveaborg , is an inhabited sea fortress built on six islands , and which now forms part of the city of Helsinki, the capital of Finland.Suomenlinna is a UNESCO World Heritage site and popular with both tourists and locals, who...
60°08′37"N 24°59′04"E. It included the islands of Kustaanmiekka, Susisaari, Iso Mustasaari, Pikku Mustasaari, Länsi-Mustasaari, Särkkä and the skerry
Skerry
A skerry is a small rocky island, usually defined to be too small for habitation. It may simply be a rocky reef. A skerry can also be called a low sea stack....
of Pormestarinluoto. Except for the smaller Särkkä and Pormestarinluoto the islands were connected by bridges or joined together. The islands housed the fortress commander and headquarters along with the main telephone exchange and the largest dry dock in Finland at the time. The citadel also had weapons and ammunition depots and other storage areas. Most of the fortification works were concentrated on other islands, and of the older armament only one battery of three 11 inch guns remained in active service in Kustaanmiekka island. To guard Kustaanmiekansalmi strait two batteries of 57 mm guns were built, one on Kustaanmiekka and one on Iso-Mustasaari island. A third battery of 57 mm guns on Länsi-Mustasaari guarded Särkänsalmi strait.
Lonna
Lonna 60°9′16.17"N 24°59′23.2"E is a small island north of Iso Mustasaari that was used as the main naval mine depot of Krepost Sveaborg. The island had three masonry and one wooden mine storage magazines and workshops, living quarters and equipment storage for mine company ships. At the end of the war the magazines had nearly 500 mines stored with another 650 mines in the open.Vallisaari, Kuninkaansaari and Nuottasaari
Vallisaari 60°8′8.96"N 25°0′6.45"E and Kuninkaansaari 60°8′4.95"N 25°1′5.78"E are located between Suomenlinna and Santahamina. The two islands were joined by a causewayCauseway
In modern usage, a causeway is a road or railway elevated, usually across a broad body of water or wetland.- Etymology :When first used, the word appeared in a form such as “causey way” making clear its derivation from the earlier form “causey”. This word seems to have come from the same source by...
across Kukisalmi strait at the turn of the 19th and 20th centuries. From the late 19th century until the First World War Vallisaari was the most heavily fortified island of the fortress. Construction of a 6 inch Canet battery on the island began in 1912, but the guns were relocated to the outer islands on the new main line of defence at the beginning of the war. Of the older guns a five-gun battery of 11 inch model 1877 guns and six-gun battery of 11 inch mortars were still used during the war. Two of the mortars were transported to the land front in early 1915, and the rest were decommissioned and abandoned on their positions in 1916. A six-gun battery of 6 inch model 1877 siege guns on fortress carriages were transported to the land front by the end of 1914. Newer artillery included two 57 mm guns that were replaced with four 75 mm guns in October 1914. Of the Kuninkaansaari batteries one four-gun battery of 11 inch model 1877 guns was kept in service. Two of the five 11 inch mortars were also in use until 1915. The rest of the guns - five 9 inch model 1867 guns, four 6 inch model 1877 siege guns, two (possibly four) 9 inch mortars and three 11 inch mortars were moved to the land front shortly after the start of the war. Both Vallisaari and Kuninkaansaari had a 150 cm searchlight stations. Small Nuottasaari island 60°8′28.34"N 25°1′34.21"E north of Haminasalmi strait between Kuninkaansaari and Santahamina was armed with four 8 inch model 1867 guns in 1887, but the island had been disarmed by 1914.
Vasikkasaari
Vasikkasaari 60°9′10.48"N 25°0′46.93"E was used as a fuel and ammunition depot of Krepost Sveaborg. The island is located in Kruunuvuorenselkä where the inner anchorage of the fortress was, between Suomenlinna, Santahamina and Laajasalo. Three large fuel oil tanks served the naval base and two smaller diesel tanks provided fuel for the mine company (later battalion) ships of the fortress. A pumping station powered by steam engine was connected to the tanks. Eight storage magazines housed weapons, ammunition, mines and torpedoes with a narrow gauge railway built on the island connecting them to the main pier. At the start of the war a 57 mm quick fire battery was located on the island, replaced by a 75 mm anti-aircraft battery in spring 1915. The anti-aircraft battery was relocated in summer 1916. A 90 cm searchlight was also located on the island.Finnish Civil War
Krepost Sveaborg never did see action against Germany in Russian hands. After the Russian revolution the treaty of Brest-LitovskTreaty of Brest-Litovsk
The Treaty of Brest-Litovsk was a peace treaty signed on March 3, 1918, mediated by South African Andrik Fuller, at Brest-Litovsk between Russia and the Central Powers, headed by Germany, marking Russia's exit from World War I.While the treaty was practically obsolete before the end of the year,...
ended Russia's participation in the First World War. The treaty affirmed the independence of Finland and required Russian troops to leave from the country. Of the approximately 35 000 Russian soldiers and sailors who were around Helsinki in January 1918 most were demobilized and sent home or simply left by 15 March. Around one thousand joined the Finnish Red Guards
Red Guards (Finland)
The Red Guards formed the army of Red Finland during the Finnish Civil War in 1918. The combined strength of the Red Guard was about 30,000 at the beginning of the Civil War, and peaked at 90,000-120,000 during the course of the conflict....
in the Finnish Civil War. The Soviet leadership ordered Krepost Sveaborg headquarters to begin preparations to abandon the fortress and destroy what could not be evacuated in case it would fall in to German hands. Some field guns were transported to Russia, but all the coastal guns were left. On 3 April 1918 German Baltic Sea Division
Baltic Sea Division
The Baltic Sea Division was a 10,000 man German military unit commanded by Rüdiger von der Goltz. During the Finnish Civil War, in April 1918, it landed at Hanko and moved towards Helsinki and Lahti. The Baltic Sea Division quickly took back Helsinki from the Social Democrats of Finland, who had...
landed in Hanko, after being requested by the White Senate of Vaasa
Senate of Finland
The Senate of Finland combined the functions of cabinet and supreme court in the Grand Duchy of Finland from 1816 to 1917 and in the independent Republic of Finland from 1917 to 1918....
to participate in the Finnish Civil War against the Reds. Russian Baltic fleet officers had made an agreement with the Germans allowing a safe departure for the warships and disarming the fortress. Most of the Russian ships left by mid-April, but the last ships left only in May-June 1918. The disarmament - removing locks from the guns, cutting the cables controlling the mines and destroying the mine control stations - had to be done in secret as an agreement between Soviet government and Finnish Red Guards had promised the latter all the fortifications. When the Germans arrived in Helsinki the Red Guard could only use some of the land front fortifications in Leppävaara and Ruskeasuo, and the Germans with a well equipped and trained numerically superior force quickly captured Helsinki between 11th and 13 April. The Russian guards ceded the coastal forts to Germans according the their agreement. The disarmament of Krepost Sveaborg, denying the Reds from using it, was used in White propaganda
Propaganda
Propaganda is a form of communication that is aimed at influencing the attitude of a community toward some cause or position so as to benefit oneself or one's group....
by how the engineer Allan Staffans had duped the Russians and removed the locks without authorization; but actually the disarmament occurred with the order of the fortress commander and with the knowledge of naval headquarters. On 12 May Krepost Sveaborg was renamed Suomenlinna to celebrate the new independency.
Later history
After First World War the fortifications of Krepost Sveaborg were taken over by Finland. Most of the land front fortifications were disarmed, stripped of useful equipment and abandoned. Much of the land front fortifications with steel reinforcements were destroyed in the inter war period and the steel sold as scrap. During the Second World War an inventory of the land front fortifications was conducted regarding their usefulness, with the larger shelters quarried into the rock under particular interest as facilities for war industry, emergency hospitals or storage. Some of the land front shelters are still used as storage space. As settlement spread during the urbanization after the Second World War many of the fortifications were destroyed as new suburbs were constructed. The coastal fortifications were used by the Finnish coastal artillery to protect Helsinki. Most of the islands remained in military use and were thus spared from vandalism. All structures of the Krepost Sveaborg fortifications around Helsinki, both land and sea fronts, were declared protected historical sites by the Finnish National Board of AntiquitiesFinnish National Board of Antiquities
The Finnish National Board of Antiquities preserves Finland’s material cultural heritage: collects, studies and distributes knowledge of it. The Board is a cultural and research institution, but it is also a government authority charged with the protection of archaeological sites, built heritage,...
in 1971.
Present day condition
While much of land front fortifications have been destroyed, many areas have been more or less preserved and some sections have been partly restored. In Vantaa Länsiniemi and Rajakylä areas have been cleared from rubbish and vegetation. In Espoo Laajalahti, Mäkkylä, Ormberget and Ruukinranta areas have also been cleared. In Helsinki trees threating the structure of one of the older 1914 redoubts in Rajakallio have been cut, and the city planning department has made a plan regarding the maintenance of the cleared areas and restoring new ones. Of the coastal forts, all main line of defence islands except Pyöräsaari and Harmaja are still in military use and forbidden from civilians, and Harmaja is used by the Finnish Maritime Administration as a pilot station. A coastal artillery museum has been built on Kuivasaari and the island is no longer in active military use, but still officially restricted area. Visitors are allowed but only in organized tours. It is planned to transfer Kuivasaari, together with Rysäkari, into civilian authorities. Skatanniemi cape is the only area of the main line of defence that is easily visited. The central citadel of Suomenlinna is a major tourist attraction and UNESCO World Heritage SiteWorld Heritage Site
A UNESCO World Heritage Site is a place that is listed by the UNESCO as of special cultural or physical significance...
with regular ferry connection. The islands of Vallisaari and Kuninkaansaari are also currently being transferred to civilian authorities, with military tentatively scheduled to leave the islands by 2012. Pihlajasaaret is a Helsinki city recreation area open to public with regular ferry connection during summertime. Vasikkasaari and Lonna are also civilian areas open to visit, but more difficult to reach.