The Albacore-class gunboat, also known as "Crimean gunboat", was a class of 98 gunboats built for the Royal Navy in 1855 and 1856 for use in the 1853-1856 Crimean War.[1] The design of the class, by W. H. Walker, was approved on 18 April 1855. The first vessels were ordered the same day, and 48 were on order by July; a second batch, which included Surly, were ordered in early October.[2]
The Albacore class was almost identical to the preceding Dapper class, also designed by W.H. Walker. The ships were wooden-hulled, with both steam power and sails, and of shallow draught for coastal bombardment in the shallow waters of the Baltic and Black Seas during the Crimean War.[1]
The Albacore-class vessels measured 106 feet (32 m) in length at the gundeck and 93 feet 2+1⁄2 inches (28.410 m) at the keel. They were 22 feet (6.7 m) in beam, 8 feet (2.4 m) deep in the hold and had a draught of 6 feet 6 inches (1.98 m). Their displacement was 284 tons and they measured 23268⁄94 tons Builder's Old Measurement.[2] The Albacore-class carried a crew of 36-40 men.[2]
One of the vessels of the class, HMS Surly, cost £9,867, of which the hull accounted for £5,656 and machinery £3,298.[3]
Half of the ships had two-cylinder horizontal single-expansion trunk steam engines, built by John Penn and Sons, with two boilers. The other half had two-cylinder horizontal single-expansion direct-acting steam engines, built by Maudslay, Sons and Field, with three boilers. Both versions provided 60 nominal horsepower through a single screw, sufficient for 7.5 knots (13.9 km/h; 8.6 mph).[1]
Ships of the class were armed with one 68-pounder (95 cwt) muzzle-loading smoothbore gun, one 32-pounder muzzle-loading smoothbore gun (originally two 68-pounders were planned but the forward gun was substituted by a 32-pounder) and two 24-pounder howitzers.[1]