Defence-class ironclad

British warship class

The Defence class ironclads were a class of two warships built for the Royal Navy between 1859 and 1862. The ships were designed as armoured frigates in response to an invasion scare sparked by the launch of the French ironclad Gloire and her three sisters in 1858. They were initially armed with a mix of rifled breech loading and muzzle loading smoothbore guns, but the Armstrong breech loading guns proved unreliable and were withdrawn from service after a few years. Both ships were initially assigned to the Channel Squadron, but was transferred to the Mediterranean Squadron in 1864. The ships were rearmed in the late 1860s after the completion of their first commission. They alternated between assignments with the fleet and guardship duties with the First Reserve for the rest of their careers. Resistance was the first to be paid off in 1880 and was used as a target for gunnery and torpedo trials beginning in 1885. She was sold for ship breaking in 1898, but wrecked en route to the breaker's yard. was paid off in 1885 and she became a stationary training ship in 1890 until she was sold for scrap in 1935.

In 1859 the Admiralty was not yet convinced that the very expensive (£377,000) s, had to be accepted as the norm. They noted that the armour plate of the Warriors was adequate to deflect all ordnance currently afloat, and high speed was not necessary to prevent existing wooden ships from massing their fire against the ironclads. Their Lordships therefore requested a design which, while carrying the same armour, was smaller and slower, and thus cheaper, than the Warriors. Rear Admiral Sir Baldwin Wake Walker, Controller of the Navy, proposed that six ships be built to this design, but he was over ruled and only two were ordered on 14 December 1859.

The Defence class was 280 feet (85 m) long between perpendiculars and 291 feet (89 m) long overall. They had a beam of 54 feet (16 m) and a draught of 26 feet (8 m). The ships displaced and had a tonnage of 3,710 tons burthen. Unlike their predecessors, they were fitted with a ram in the shape of a plough. The ends of the hull were subdivided by watertight transverse bulkheads and had a partial double bottom. Each ship had a complement of 460 officers and ratings. The Defence class was 128 feet (39 m) shorter overall and displaced more than less than the Warrior class ironclads.

The Defence class ships had a single two cylinder trunk steam engine made by John Penn and Sons driving a single 21 feet (6 m) propeller. Four rectangular boilers enough to steam at The lower masts and bowsprit were made of iron to withstand the shock of ramming. Both ships could make about under sail alone. To reduce wind resistance while under sail alone, the funnel was semi retractable. Similarly, the propeller could be hoisted up into the stern of the ship to reduce drag while under sail.

The armament of the Defence class ships was intended to be 18 smoothbore, muzzle loading 68 pounder guns, eight on each side on the main deck and one each fore and aft as chase guns on the upper deck, plus four Armstrong 40 pounder guns, an early rifled breech loader (RBL) design, as saluting guns. The 68 pounder weighed and had a range of with solid shot. During construction the armament was changed to six (Defence) or eight (Resistance) of the new Armstrong rifled 7" breech loading 110 pounder guns, ten 68 pounders, and either two 32 pounder smoothbores (Resistance) or four breech loading guns (Defence). The innovative 110 pounder, whose shell could reach Furthermore, the 110 pounders proved problematic in service. They were labour intensive to load and fire, and some of them blew up when other ships used them in action. After that, they were only used with a reduced propellant charge, which left them useless in practice. Both ships were rearmed in the late 1860s with 14 seven inch and two eight inch rifled muzzle loading guns. The new guns were heavier so fewer could be carried. On both ships the eight inch guns were mounted amidships on the main deck on the broadside and a pair of seven inch guns were mounted on the upper deck as fore and aft chase guns. Eight of the remaining seven inch guns were also placed on the main deck on the broadside where they were protected by the ship's armour, but one pair was on the main deck further aft where they were not protected by armour. The two ships differed where the last pair of seven inch guns was positioned: Defence mounted them on the main deck, forward of the armour, while Resistance mounted hers on the upper deck. The shell of the weighed while the gun itself weighed It had a muzzle velocity of and was credited with the ability to penetrate of wrought iron armour at the muzzle. The seven inch gun fired a shell and could penetrate armour. All of the guns could fire both solid shot and explosive shells.

The Defence class ships had a wrought iron armour belt, thick, that covered 140 feet (43 m) amidships. The armour extended from upper deck level to 6 feet (2 m) below the waterline.