Steam Gun Boat
Encyclopedia
The Steam Gun Boat (SGB) was a Royal Navy
term for a class of small naval vessels used during the Second World War. The class consisted of nine gun boats
, powered by steam, and built from 1940 to 1942 for the Coastal Forces of the Royal Navy
.
They were developed in parallel with the Fairmile D motor torpedo boat
s ("Dog boats"), specifically as a response to the need to hunt down German E-boats and also as a response to the scarcity of suitable diesel engines. While sixty were planned only an initial batch of nine were ordered on 8 November 1940, of which seven were completed.
) and MTB (Motor Torpedo Boat
) in the same fashion as did the German S-boats. They were the largest of the Coastal forces vessels, and were the only ones to be built of steel (all other Coastal Forces craft were of wood). They resembled a miniature destroyer, and were perhaps the most graceful of all the craft produced during WW2. However their comparatively large silhouette was a drawback, making them too easy a target for the faster German craft.
They were 145 feet 8 inches long and had a displacement of 172 tons (202 tons fully fueled). They were powered by two 4,000 hp steam turbines using special flash boilers. These boilers proved to be particularly vulnerable to attack and - once the vessel had broken down - required a major effort to repair. Steam had the advantage of quietness but demanded a large hull. Large wooden hulls were not feasible for mass production so steel was used. This meant hulls and machinery were beyond the scope of the small yards engaged in the rapid expansion of the coastal forces, and the SGB thus competed for berths in yards hard put to produce urgently required convoy escorts. Also they competed in the demand for mild steel and steam power plants against the more urgently demanded destroyers; accordingly the planned 51 further vessels were never ordered, while the two units ordered from Thornycroft were never begun due to enemy action. The seven vessels actually completed were built by Yarrow
, Hawthorn Leslie, J. Samuel White
and William Denny and Brothers
, entering service by the middle of 1942.
Fuel consumption was heavy with the added disadvantage that, where a petrol boat could start from cold and get away immediately, the SGB had to remain in steam. Over time the addition of 18 mm (0.7 in) protective plate over the sides of the boiler and engine rooms, together with the extra armament and crew, increased the displacement to 260 tons and their service speed was consequentially reduced to 30 kts.
Veritable battleships of the coastal forces, the Steam Gun Boats were heavily-armed and could maintain high speed in a seaway. In action E-boat commanders respected the SGBs almost as much as destroyers.
, son of the Antarctic
explorer Captain Robert Scott
and later a noted ornithologist, conservationist and broadcaster. Their first fleet action took place in the Baie de Seine (the Seine Estuary) shortly after midnight on 19 June, when two vessels - SGB 7 and 8, under the joint command of Lt. J. D. Ritchie, in company with the Hunt class destroyer
HMS Albrighton encountered several E-boats escorting two German merchantmen. SGB 7 was sunk in this action; as a consequence the Admiralty noted their vulnerability and refitted them with the additional armour over their engine and boiler rooms, as mentioned above. At the same time the six survivors were renamed after wildlife in the form "SGB Grey...." .
These boats formed the 1st SGB Flotilla which was initially formed at Portsmouth, but later based at HMS Aggressive
, Newhaven, Sussex on the south coast of England.
SGB 5 was damaged in the Dieppe raid
after meeting a German convoy of R boat
s.
In 1944 the six survivors were all converted to fast minesweeper
s and all (except SGB9/Grey Goose) were sold off in the years after the war.
SGB9 remained in service as a propulsion trials vessel from 1952 to 1956, her steam engines replaced by Vospers
with a pair of experimental Rolls-Royce
RM60 marine gas turbines and becoming the first vessel to rely solely on gas turbines for propulsion. The highly advanced turbines featured intercooled compressors and recuperators to boost turbine power output and reduce fuel consumption. Over the original steam machinery, the gas turbine powerplant provided 35% more power while weighing 50% less and using 25% less space. Although the experimental powerplant proved very successful, it was too complex and supporting technology too immature for wider service at that time and SGB9 was placed in reserve at the end of the trials in 1957. With the experimental engines removed SGB9 was sold off in 1958, becoming a mercantile repair hulk. Sold in 1984, the hulk was converted to a houseboat and renamed Anserava. She is currently moored on the River Medway
near Hoo St Werburgh
in Kent
, England
.
Royal Navy
The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...
term for a class of small naval vessels used during the Second World War. The class consisted of nine gun boats
Gunboat
A gunboat is a naval watercraft designed for the express purpose of carrying one or more guns to bombard coastal targets, as opposed to those military craft designed for naval warfare, or for ferrying troops or supplies.-History:...
, powered by steam, and built from 1940 to 1942 for the Coastal Forces of the Royal Navy
Royal Navy
The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...
.
They were developed in parallel with the Fairmile D motor torpedo boat
Fairmile D motor torpedo boat
The Fairmile D motor torpedo boat was a type of British Motor Torpedo Boat designed by Bill Holt and conceived by Fairmile Marine for the Royal Navy....
s ("Dog boats"), specifically as a response to the need to hunt down German E-boats and also as a response to the scarcity of suitable diesel engines. While sixty were planned only an initial batch of nine were ordered on 8 November 1940, of which seven were completed.
Design
The Steam Gun Boats were conceived to answer the seeming need for a craft which was large enough to put to sea in rough weather and which could operate both as a 'super-gunboat' and a torpedo carrier, combining the functions of the MGB (Motor Gun BoatMotor Gun Boat
Motor Gun Boat was a Royal Navy term for a small military vessel of the Second World War. They were physically similar to the Motor Torpedo Boats but equipped with a mix of guns instead of torpedoes. Their small size and high speed made them difficult targets for E-boats or torpedo bombers, but...
) and MTB (Motor Torpedo Boat
Motor Torpedo Boat
Motor Torpedo Boat was the name given to fast torpedo boats by the Royal Navy, and the Royal Canadian Navy.The capitalised term is generally used for the Royal Navy boats and abbreviated to "MTB"...
) in the same fashion as did the German S-boats. They were the largest of the Coastal forces vessels, and were the only ones to be built of steel (all other Coastal Forces craft were of wood). They resembled a miniature destroyer, and were perhaps the most graceful of all the craft produced during WW2. However their comparatively large silhouette was a drawback, making them too easy a target for the faster German craft.
They were 145 feet 8 inches long and had a displacement of 172 tons (202 tons fully fueled). They were powered by two 4,000 hp steam turbines using special flash boilers. These boilers proved to be particularly vulnerable to attack and - once the vessel had broken down - required a major effort to repair. Steam had the advantage of quietness but demanded a large hull. Large wooden hulls were not feasible for mass production so steel was used. This meant hulls and machinery were beyond the scope of the small yards engaged in the rapid expansion of the coastal forces, and the SGB thus competed for berths in yards hard put to produce urgently required convoy escorts. Also they competed in the demand for mild steel and steam power plants against the more urgently demanded destroyers; accordingly the planned 51 further vessels were never ordered, while the two units ordered from Thornycroft were never begun due to enemy action. The seven vessels actually completed were built by Yarrow
Yarrow
Achillea millefolium or yarrow is a flowering plant in the family Asteraceae, native to the Northern Hemisphere. In New Mexico and southern Colorado, it is called plumajillo, or "little feather", for the shape of the leaves. In antiquity, yarrow was known as herbal militaris, for its use in...
, Hawthorn Leslie, J. Samuel White
J. Samuel White
J. Samuel White was a British shipbuilding firm based in Cowes, taking its name from John Samuel White . It came to prominence during the Victorian era...
and William Denny and Brothers
William Denny and Brothers
William Denny and Brothers Limited, and often referred to simply as Denny, were a Scottish shipbuilding company.-History:The Company was founded by Peter Denny in 1840 and based in Dumbarton, on the River Clyde. Although the Denny yard was situated near the junction of the River Clyde and the River...
, entering service by the middle of 1942.
Fuel consumption was heavy with the added disadvantage that, where a petrol boat could start from cold and get away immediately, the SGB had to remain in steam. Over time the addition of 18 mm (0.7 in) protective plate over the sides of the boiler and engine rooms, together with the extra armament and crew, increased the displacement to 260 tons and their service speed was consequentially reduced to 30 kts.
Veritable battleships of the coastal forces, the Steam Gun Boats were heavily-armed and could maintain high speed in a seaway. In action E-boat commanders respected the SGBs almost as much as destroyers.
Service
The nine boats ordered initially received the designation SGB 1 to 9 (of which numbers 1 and 2 were cancelled). The 1st SGB Flotilla was formed at Portsmouth by mid-June 1942, under the command of Lt-Cmdr. Peter ScottPeter Scott
Sir Peter Markham Scott, CH, CBE, DSC and Bar, MID, FRS, FZS, was a British ornithologist, conservationist, painter, naval officer and sportsman....
, son of the Antarctic
Antarctic
The Antarctic is the region around the Earth's South Pole, opposite the Arctic region around the North Pole. The Antarctic comprises the continent of Antarctica and the ice shelves, waters and island territories in the Southern Ocean situated south of the Antarctic Convergence...
explorer Captain Robert Scott
Robert Falcon Scott
Captain Robert Falcon Scott, CVO was a Royal Navy officer and explorer who led two expeditions to the Antarctic regions: the Discovery Expedition, 1901–04, and the ill-fated Terra Nova Expedition, 1910–13...
and later a noted ornithologist, conservationist and broadcaster. Their first fleet action took place in the Baie de Seine (the Seine Estuary) shortly after midnight on 19 June, when two vessels - SGB 7 and 8, under the joint command of Lt. J. D. Ritchie, in company with the Hunt class destroyer
Hunt class destroyer
The Hunt class was a class of Destroyer escort of the Royal Navy. The first vessels were ordered early in 1939, and the class saw extensive service in World War II, particularly on the British East Coast and Mediterranean convoys. They were named after British fox hunts...
HMS Albrighton encountered several E-boats escorting two German merchantmen. SGB 7 was sunk in this action; as a consequence the Admiralty noted their vulnerability and refitted them with the additional armour over their engine and boiler rooms, as mentioned above. At the same time the six survivors were renamed after wildlife in the form "SGB Grey...." .
Boats
Nine vessels below were all ordered on 8 November 1940.| Ship | Builder | Laid down | Launched | Commissioned | Fate |
|---|---|---|---|---|---|
| SGB1 | Thornycroft, Woolston | Cancelled | |||
| SGB2 | Thornycroft, Woolston | Cancelled | |||
| SGB3/Grey Seal | Yarrow Yarrow Shipbuilders Yarrow Limited , often styled as simply Yarrows, was a major shipbuilding firm based in the Scotstoun district of Glasgow on the River Clyde... , Scotstoun Scotstoun Scotstoun is a historic district of Glasgow, Scotland, west of Glasgow City Centre. It is bounded by Yoker and Knightswood to the west, Victoria Park, Broomhill and Whiteinch to the east, Jordanhill to the north and the River Clyde to the south... |
24 January 1941 | 29 August 1941 | 21 February 1942 | For sale 20 August 1949 |
| SGB4/Grey Fox | Yarrow Yarrow Shipbuilders Yarrow Limited , often styled as simply Yarrows, was a major shipbuilding firm based in the Scotstoun district of Glasgow on the River Clyde... , Scotstoun Scotstoun Scotstoun is a historic district of Glasgow, Scotland, west of Glasgow City Centre. It is bounded by Yoker and Knightswood to the west, Victoria Park, Broomhill and Whiteinch to the east, Jordanhill to the north and the River Clyde to the south... |
24 January 1941 | 25 September 1941 | 15 March 1942 | For sale October 1947 |
| SGB5/Grey Owl | Hawthorn Leslie, Hebburn Hebburn Hebburn is a small town situated on the south bank of the River Tyne in North East England, sandwiched between the towns of Jarrow and Bill Quay... |
17 April 1941 | 27 August 1941 | 1 April 1942 | Sold to British Iron & Steel and scrapped 15 December 1949 |
| SGB6/Grey Shark | Hawthorn Leslie, Hebburn Hebburn Hebburn is a small town situated on the south bank of the River Tyne in North East England, sandwiched between the towns of Jarrow and Bill Quay... |
28 March 1941 | 17 November 1941 | 30 April 1942 | Sold 13 October 1947. Houseboat in 1949 |
| SGB7 | Denny William Denny and Brothers William Denny and Brothers Limited, and often referred to simply as Denny, were a Scottish shipbuilding company.-History:The Company was founded by Peter Denny in 1840 and based in Dumbarton, on the River Clyde. Although the Denny yard was situated near the junction of the River Clyde and the River... , Dunbarton |
3 February 1941 | 25 September 1941 | 11 March 1942 | Sunk by gunfire from German surface vessels in the Seine Estuary 19 June 1942 |
| SGB8/Grey Wolf | Denny William Denny and Brothers William Denny and Brothers Limited, and often referred to simply as Denny, were a Scottish shipbuilding company.-History:The Company was founded by Peter Denny in 1840 and based in Dumbarton, on the River Clyde. Although the Denny yard was situated near the junction of the River Clyde and the River... , Dunbarton |
3 February 1941 | 3 November 1941 | 17 April 1942 | Sold 3 February 1948 |
| SGB9/Grey Goose | J. Samuel White J. Samuel White J. Samuel White was a British shipbuilding firm based in Cowes, taking its name from John Samuel White . It came to prominence during the Victorian era... , Cowes Cowes Cowes is an English seaport town and civil parish on the Isle of Wight. Cowes is located on the west bank of the estuary of the River Medina facing the smaller town of East Cowes on the east Bank... |
23 January 1941 | 14 February 1942 | 4 July 1942 | Sold about 1957. Converted to houseboat, currently moored at Hoo St Werburgh Hoo St Werburgh Hoo St Werburgh is one of several villages on the Hoo Peninsula in Kent, England, to bear the name Hoo. It constitutes a civil parish in the borough of Medway, with a population of 7,356 at the 2001 census.- History :... . |
These boats formed the 1st SGB Flotilla which was initially formed at Portsmouth, but later based at HMS Aggressive
HMS Aggressive (shore establishment)
HMS Aggressive was a shore establishment of the British Royal Navy during World War II, based at Newhaven, East Sussex.-Service history:Founded in November 1941 as a base for Coastal Forces, it was first named Forward II, but was renamed Aggressive on 4 November 1942...
, Newhaven, Sussex on the south coast of England.
SGB 5 was damaged in the Dieppe raid
Dieppe Raid
The Dieppe Raid, also known as the Battle of Dieppe, Operation Rutter or later on Operation Jubilee, during the Second World War, was an Allied attack on the German-occupied port of Dieppe on the northern coast of France on 19 August 1942. The assault began at 5:00 AM and by 10:50 AM the Allied...
after meeting a German convoy of R boat
R boat
The R boats were a group of small minesweepers but used for several purposes during the Second World War.A total of 424 boats were built for the Kriegsmarine before and during World War II. The German Navy used them in every theatre including the Baltic, Mediterranean and the Black Sea...
s.
In 1944 the six survivors were all converted to fast minesweeper
Minesweeper (ship)
A minesweeper is a small naval warship designed to counter the threat posed by naval mines. Minesweepers generally detect then neutralize mines in advance of other naval operations.-History:...
s and all (except SGB9/Grey Goose) were sold off in the years after the war.
SGB9 remained in service as a propulsion trials vessel from 1952 to 1956, her steam engines replaced by Vospers
Vosper & Company
Vosper & Company, often referred to simply as Vospers, was a British shipbuilding company based in Portsmouth, England.-History:The Company was established in 1871 by Herbert Edward Vosper, concentrating on ship repair and refitting work....
with a pair of experimental Rolls-Royce
Rolls-Royce plc
Rolls-Royce Group plc is a global power systems company headquartered in the City of Westminster, London, United Kingdom. It is the world’s second-largest maker of aircraft engines , and also has major businesses in the marine propulsion and energy sectors. Through its defence-related activities...
RM60 marine gas turbines and becoming the first vessel to rely solely on gas turbines for propulsion. The highly advanced turbines featured intercooled compressors and recuperators to boost turbine power output and reduce fuel consumption. Over the original steam machinery, the gas turbine powerplant provided 35% more power while weighing 50% less and using 25% less space. Although the experimental powerplant proved very successful, it was too complex and supporting technology too immature for wider service at that time and SGB9 was placed in reserve at the end of the trials in 1957. With the experimental engines removed SGB9 was sold off in 1958, becoming a mercantile repair hulk. Sold in 1984, the hulk was converted to a houseboat and renamed Anserava. She is currently moored on the River Medway
River Medway
The River Medway, which is almost entirely in Kent, England, flows for from just inside the West Sussex border to the point where it enters the Thames Estuary....
near Hoo St Werburgh
Hoo St Werburgh
Hoo St Werburgh is one of several villages on the Hoo Peninsula in Kent, England, to bear the name Hoo. It constitutes a civil parish in the borough of Medway, with a population of 7,356 at the 2001 census.- History :...
in Kent
Kent
Kent is a county in southeast England, and is one of the home counties. It borders East Sussex, Surrey and Greater London and has a defined boundary with Essex in the middle of the Thames Estuary. The ceremonial county boundaries of Kent include the shire county of Kent and the unitary borough of...
, England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
.
