The eighth HMS Shannon was the first British armoured cruiser. She was the last 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...

 ironclad to be built which had a propeller

Propeller

A propeller is a type of fan that transmits power by converting rotational motion into thrust. A pressure difference is produced between the forward and rear surfaces of the airfoil-shaped blade, and a fluid is accelerated behind the blade. Propeller dynamics can be modeled by both Bernoulli's...

 that could be hoisted out of the water to reduce drag

Drag (physics)

In fluid dynamics, drag refers to forces which act on a solid object in the direction of the relative fluid flow velocity...

 when she was under sail, and the first to have an armoured deck

Deck (ship)

A deck is a permanent covering over a compartment or a hull of a ship. On a boat or ship, the primary deck is the horizontal structure which forms the 'roof' for the hull, which both strengthens the hull and serves as the primary working surface...

.

Design

Shannon was built in response to two threats. The instructions of the Admiralty to the designer, Nathaniel Barnaby

Nathaniel Barnaby

Sir Nathaniel Barnaby, KCB was Chief Constructor of the Royal Navy from 1872 to 1885....

, were to design an ironclad "capable of competing with the second class Ironclads of foreign navies". This meant in particular the ten French armoured corvettes of the Alma

Alma class ironclad

The Alma class ironclads were a group of seven wooden-hulled, armored corvettes built for the French Navy in the mid to late 1860s. Three of the ships attempted to blockade Prussian ports in the Baltic Sea in 1870 during the Franco-Prussian War...

 and La Galissonnière

La Galissonnière class ironclad

The La Galissonnière class ironclads were a group of wooden-hulled, armored corvettes built for the French Navy during the 1870s, meant as a heavier armed and faster version of the . While all three ships were begun before the Franco-Prussian War of 1870–71, the construction of the last two ships...

 classes, though the ironclads of the smaller navies of Asia the Americas also featured. The British counter to these ships were the Audacious and Swiftsure classes of second-class ironclad of the 1860s. Shannon 's design was in the lineage of these ships, though the tactical landscape was changing. At the same time as Shannon was being planned, the Russian navy launched the first armoured cruisers, General Admiral

Russian cruiser General-Admiral (1873)

General-Admiral was the lead ship of the armored cruisers built for the Imperial Russian Navy in the early 1870s. She is generally considered as the first true armored cruiser.-Design and description:...

 and her sister Gerzog Edinburgski. These ships were intended for the traditional cruiser mission of commerce raiding

Commerce raiding

Commerce raiding or guerre de course is a form of naval warfare used to destroy or disrupt the logistics of an enemy on the open sea by attacking its merchant shipping, rather than engaging the combatants themselves or enforcing a blockade against them.Commerce raiding was heavily criticised by...

, but were armoured and armed on the same scale as a second-class ironclad. The existence of these ships mean that Shannon was now expected to act as a counter to them, and perform the commerce protection missions which had previously been the preserve of unarmoured cruisers, most recently the Inconstant

HMS Inconstant (1868)

HMS Inconstant was an iron screw frigate of the Royal Navy. She was launched on 12 November 1868 and became a training ship in 1906, renamed Impregnable II. She became the Navy's torpedo school ship in January 1922 and was renamed Defiance IV, and Defiance II in December 1930, before being finally...

.

Shannon was armed with two 10-inch guns

RML 10 inch 18 ton gun

The RML 10 inch guns Mk I - Mk II were large rifled muzzle-loading guns designed for British battleships and monitors. They were also fitted to the Bouncer-class flat-iron gunboats.-Design:...

 in armoured embrasures facing towards the bow, six 9-inch guns

RML 9 inch 12 ton gun

The RML 9 inch guns Mark I - Mark VI were large rifled muzzle-loading guns used as primary armament on smaller British ironclad battleships and secondary armament on larger battleships, and also ashore for coast defence.-Design:...

 on the open deck amidships, and a seventh 9-inch gun facing astern. The astern gun could be fired from either of two unarmoured embrasures, one on each side of the ship. She was also equipped with an unusual detachable ram, which was meant to be removed in peactime to reduce the risk of accidentally ramming another warship. The ram was supposed to be stowed on board and attached in wartime; however this proved to be a very impractical arrangement.

Shannon was armoured in an unconventional manner. An armoured belt 9 ft tall and between 9 in and 6 in thick ran for most of the length of the ship, but stopped 60 ft from the bows. Above the belt was an armoured deck 1.5 in thick, the first such armoured deck on a British warship. At the point the belt ended, a 9 in armoured bulkhead ran across the ship, the top of which formed the embrasures for the 10-inch guns on the upper deck. From the bottom of this bulkhead, a 3 in thick armoured deck extended to the bow, at a level 10 ft below the waterline. The space above this forward armoured deck was filled with coal bunkers and stores to limit any flooding.

The 9-inch guns were unarmoured (though the armoured bulkhead did protect them against raking fire from ahead) and would have been very exposed in combat. In an action, it was hoped to attempt to ram the enemy while firing with the forward guns and preparing the 9-inch broadside. The crews could then retreat into the armoured part of the ship. If the ramming failed then the guns could be fired electrically as Shannon passed her target.

Shannon could use both sail or steam power. While steam was much preferred for combat, sail propulsion was considered vital for a ship intended to operate worldwide. She was given a lifting screw in order to increase her efficiency under sail, the last Royal Navy warship to be so equipped. She had three masts, and was initially given a ship rig

Full rigged ship

A full rigged ship or fully rigged ship is a sailing vessel with three or more masts, all of them square rigged. A full rigged ship is said to have a ship rig....

 with 24000 ft² of sail, a point insisted on by the Director of Naval Operations, Capt. Hood

Arthur Hood, 1st Baron Hood of Avalon

Admiral Arthur William Acland Hood, 1st Baron Hood of Avalon GCB , was an officer of the Royal Navy who held command during the Crimean War and later served as First Naval Lord.- Early life :...

. In service, this was reduced to a barque rig

Barque

A barque, barc, or bark is a type of sailing vessel with three or more masts.- History of the term :The word barque appears to have come from the Greek word baris, a term for an Egyptian boat. This entered Latin as barca, which gave rise to the Italian barca, Spanish barco, and the French barge and...

 with 21500 ft². She was equipped with Laird two-cylinder compound engines, the high-pressure cylinders being 44 in in diameter and the low-pressure cylinders 85 in. Steam came from eight cylindrical boilers at 70 lb pressure. Her design top speed was 13 knots (24 km/h), but her best actual speed was 12.25 knots (23 km/h). To reduce fouling

Fouling

Fouling refers to the accumulation of unwanted material on solid surfaces, most often in an aquatic environment. The fouling material can consist of either living organisms or a non-living substance...

, she had zinc

Zinc

Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...

 and wood

Wood

Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...

 sheathing

Copper sheathing

Copper sheathing was the practice of protecting the under-water hull of a ship or boat through the use of copper plates affixed to the outside of the hull. It was pioneered and developed by the Royal Navy during the 18th century.-Development:...

 on her hull.

Service

Shannon was something of a failure as a warship. While she accomplished more than Swiftsure or Audacious on a more limited displacement, and was the equal of a foreign 'station ironclad', she turned out to be far too slow to be an effective cruiser. While her heavy reliance on sailing efficiency was inevitable given her role, this was incompatible with the speed required to catch a foreign cruiser.

These problems meant that Shannon spent very little time on the overseas stations she was designed for. She was commissioned in July 1877, but she was found to be over-weight and there were problems with her engines, which kept her in dock until March 1878, when she went on a shakedown cruise with the Channel Fleet

Channel Fleet

The Channel Fleet was the Royal Navy formation of warships that defended the waters of the English Channel from 1690 to 1909.-History:The Channel Fleet dates back at least to 1690 when its role was to defend England against the French threat under the leadership of Edward Russell, 1st Earl of...

. In April 1878 she departed for the China Station but was recalled from there in July, and went into dock for further changes. In December 1878 she was commissioned again, serving in Channel and Mediterranean fleets, and was despatched to the Pacific in July 1879, returning in July 1881 when she was refitted. In the Pacific, Shannon was the only ship equipped with 10-inch guns, and no spare ammunition of this calibre was kept at Esquimault; since the expense of moving ammunition to a base that remote was prohibitive, she was prohibited from practicing with her 10-inch guns. This problem could have been addressed by replacing the 10-inch guns in the 1881 refit, but there was little purpose to doing so as Shannon would never see overseas service again.

In May 1883 she briefly became a tender to Warrior

HMS Warrior (1860)

HMS Warrior was the first iron-hulled, armour-plated warship, built for the Royal Navy in response to the first ironclad warship, the French Gloire, launched a year earlier....

 and then was relegated to being a coastguard

Her Majesty's Coastguard

Her Majesty's Coastguard is the service of the government of the United Kingdom concerned with co-ordinating air-sea rescue.HM Coastguard is a section of the Maritime and Coastguard Agency responsible for the initiation and co-ordination of all civilian maritime Search and Rescue within the UK...

 ship. During a war scare in 1885 she was briefly readied for operations. From May 1895 she was in reserve, and she was sold for breaking up in December 1899 for £10,105.

Building Programme

The following table gives the purchase cost of the members of the Shannon. Standard British practice at that time was for these costs to exclude armament and stores. In the table:

• Machinery meant "propelling machinery".
• Hull included "hydraulic machinery, gun mountings, etc."

Cost data

( BNA Brassey's Naval Annual The Naval Annual was a book that sought to bring together a large amount of information on naval subjects, which had hitherto been obtainable only by consulting numerous publications and chiefly from foreign sources... 1895)			Parkes
Hull	Machinery	Total excluding armament
£233,902	£53,367	£287,269	£302,707

External links