HMS Erin

HMS Erin was a dreadnought battleship of the Royal Navy which was originally built in response to an order placed by the Ottoman government with the British Vickers company. She was intended, when accepted for service in the Ottoman Navy, to be named OTTOMAN BATTLESHIP Reşadiye. The Ottoman intention was to procure a battleship which was at least the equal of any other ship currently afloat or building. The design was based on that of King George V, but with some features of Iron Duke. In 1914 when the First World War broke out the ship was nearly completed; at the orders of Winston Churchill, the First Lord of the Admiralty, she was seized for use by the Royal Navy.

Design and Appearance
The design was based closely on the design of King George V, but with a number of modifications. British battleships of the period were required by the Admiralty to be of a size that could be accommodated by existing docks, which imposed absolute limitations on beam and on draught. Erin was built with a greater beam and a shorter length than King George V, the greater stability so produced allowing for the installation of a heavier secondary battery and the positioning of "Q" turret one deck higher. She had only a single mast, the foremast, which supported the fighting top and was situated ahead of the forefunnel. The legs of the tripod foremast spread forward rather than the more usual aft orientation; This was to allow the ship's boats to be worked by booms from this mast, in the absence of a mainmast. As a further result of this mast arrangement the charthouse could not be built as part of the conning tower, but was built as a separate structure around the base of the mast.

She was built with a plough bow, a design which cut more cleanly through the water, leading to less water coming on board the forecastle in a heavy sea.

The two funnels were closer together than in any previous British dreadnought, and the appearance of the secondary battery was distinctive, extending as it did from "B" turret to "X" turret.

Armament
The primary armament was ten 13.5 inch (343mm) 45-calibre Mark VI guns, arranged in five double turrets all on the centre-line of the ship. "A" turret was positioned on the forecastle, with an unobstructed arc of fire over the bow of some 300 degrees. "B" turret was situated one deck higher, superfiring over "A" and with a similar arc of fire. "Q" turret was positioned between the after funnel and the after superstructure; it was situated at forecastle deck level, which was one deck level higher than the equivalent turret in the King George V-class or the Iron Duke-class ships. The arc of fire of this turret was 300 degrees over the stern at full elevation; at lower elevations the after superstructure restricted fire to 120 degrees on either beam. "Y" turret was placed on the quarterdeck, one deck level below forecastle deck level. The arc of fire over the stern was an unobstructed 300 degrees. "X" turret was immediately forward of "Y", and superfired over it with a similar arc of fire. The ammunition carried was 80 rounds per gun.

The secondary battery was more powerful than that carried by earlier or contemporary British battleships, being sixteen 6 inch (152 mm) 50-calibre Mark XVI guns disposed eight on either side in a maindeck battery extending from "B" to "X" turrets. All were twenty feet above water at normal draught. The forward three had arcs of fire from directly ahead to 40 degrees aft of the beam; the two amidships guns bore from 65 degrees ahead to 65 degrees abaft the beam; the after three bore from 40 degrees before the beam to dead astern. The forward three tended to be wet in a heavy sea. Ammunition carried was 150 rounds per gun.

Ten 3 inch (12-pounder) guns were carried high in the superstructure.

Four 21 inch (533 mm)) torpedo tubes were installed, two on either beam. Ten torpedoes were carried.

In 1917 two 3 inch anti-aircraft guns were added on the after superstructure. In 1918 runways for launching aircraft were added on the crowns of "B" and "Q" turrets.

Armour
The main waterline armour belt was twelve inches thick, and stretched from points level with the axes of "A" and "Y" barbettes. It extended to a depth below water of three foot eight inches at normal draught. Above the main belt was a narrow belt of nine-inch armour, and above that a belt of eight-inch thickness which extended up to the level of the upper deck. Both of these strakes extended for the whole length of the main belt. Forward of "A" turret the main belt was continued as a strake of six-inch thickness for about one-third of the distance to the stem, continued further by armour of four-inch thickness for a further third of this distance. The remainder of the bow was not armoured. Aft of the main belt a short extension of four-inch armour ran half-way to the stern; beyond this there was no side armour. The secondary battery was protected by five inches of armour; an anti-torpedo bulkhead of thickness of between one and two inches ran the length of the citadel and extended from the lower deck down to the level of the keel.

Four of the decks were armoured. The forecastle deck, upper deck and maindeck were all of one and a half inch armour and the middle deck was of one inch increasing to three over the machinery and magazines.

The forward bulkhead ran from the end of the main belt across the ship to the forward aspect of "A" barbette. It was eight inches thick above the maindeck, and five inches thick down to its lower limit on the lower deck. The after bulkhead was similar, running as an eight-inch thickness from the after ends of the main belt to "Y" barbette above the maindeck, and extending in five inch thickness down to the lower deck.

The turret faces were of eleven inch armour; the roofs were four inch and the turret sides three inches thick.

The armour of the barbettes was ten inches thick at the most exposed points, tapering down through nine inches and five inches to three inches (76 mm), according to the degree of protection afforded by adjacent armoured structures; deck, side armour or neighbouring turret.

The conning tower received twelve inches of armour on its exposed sides, and four inches where it was shielded by the foremast structure.

The total weight of armour applied was 4,207 tons.

Machinery
Four propellers were driven directly by four Parsons turbines. Steam to drive the turbines was produced in fifteen Babcock and Wilcox boilers with a normal working pressure of 235 pounds per square inch (PSI). The designed shaft horse power (SHP) was 26,500, and the expected maximum speed with this power was 21 kn. She could carry up to 2,120 tons of coal and 710 tons of fuel oil; her maximum range was 3,400 nmi at ten knots using coal only, and 5,300 nmi at ten knots using both coal and oil. This radius of action was significantly less than that of contemporary British battleships, but was wholly adequate for operations in the North Sea, where any action against the German High Seas Fleet would be anticipated.

Career


Erin was ordered by the Ottoman Empire originally under the name of Reşad, but was renamed Reşadiye during construction. She was laid down at Vickers shipyard on 6 December 1911, launched on 3 September 1913 and completed in August 1914. She was taken over for the Royal Navy on 22 August 1914 and renamed Erin. It has been claimed that the seizing of Erin, and the Sultân Osmân-ı Evvel (renamed Agincourt), was instrumental in bringing the Ottoman Empire into the war on the side of the Central Powers, but this is disputed given that the Ottomans and Germans had concluded a secret alliance on 2 August. An attempt by the British to compensate the Ottomans for the loss of their battleships was ignored.

On 5 September 1914 she joined the Grand Fleet at its principal war base at Scapa Flow in Orkney. She was briefly part of the fourth battle squadron, being transferred to the second battle squadron in October 1914. On 31 May 1916 she was present at the Battle of Jutland. After the deployment of the battle fleet the second battle squadron formed the head of the line; its first division consisted of King George V (the flagship of Vice-Admiral Sir T. H. Martyn Jerram), Ajax, Centurion and Erin, which was therefore the fourth ship in the line.

She remained with the Grand Fleet for the remainder of the war, seeing no further enemy action. In October 1919 she was placed in Reserve at the Nore. From December 1919 she was used at Chatham Dockyard as a turret drill ship. In July and August 1920 she underwent a refit at Devonport Dockyard. It had been intended that under the terms of the Washington treaty of 1921 she should be retained as a training ship, but a change of plan meant that this rôle was filled by Thunderer. In May 1922 she was placed on the disposal list, on 19 December 1922 she was sold to the shipbreaking firm of Cox and Danks, and in 1923 she was broken up at Queenborough.