HMS Irresistible (1898) - Technical Characteristics

Technical Characteristics

HMS Irresistible was laid down at Chatham Dockyard on 11 April 1898 and launched on 15 December 1898 in a very incomplete state to clear the building ways for the construction of battleship Venerable. Irresistible was completed in October 1901.

Irresistible had the same-calibre armament and was similar in appearance to the Majestic and Canopus classes that preceded her. She and her sister ships are often described as improved Majestics, but in design they were effectively enlarged Canopuses. The Canopus class employed Krupp armour in their construction; this possessed greater strength for a given weight compared to that of the Majestics' Harvey armour, allowing the Canopuses to be lighter and faster without sacrificing protection; however, in Irresistible, Krupp armour was used to improve protection without reducing the size of the ship. Irresistible thus was larger than the ships of the two preceding classes, and enjoyed greater protection than the Majestics and the higher speed of the Canopuses. Irresistible's armour scheme was similar to that of the Canopuses, although the armour belt ran all the way to the stern being 215 ft (66 m) long, 15 ft (4.6 m) deep and 9 in (23 cm) thick. It tapered at the stem to 3 in (7.6 cm) thick and 12 ft (3.7 m) deep, and at the stern to 1.5 in (3.8 cm) thick and 8 ft (2.4 m) deep. The main battery turrets had 10 in (25 cm) of Krupp armour on their sides and 8 in (20 cm) on their backs.

Irresistible improved on the main and secondary armament of previous classes, being upgunned from 35- to 40-cal 12 in (300 mm) guns and from 40- to 45-cal 6 in (150 mm) guns. The 12 in (300 mm) guns could be loaded at any bearing and elevation, and had a split hoist with a working chamber beneath the turrets to reduce the chance of a cordite fire spreading from the turrets to the shell and powder handling rooms and to the magazines.

Irresistible had an improved hull form that endowed better handling at high speeds than the Majestics and inward-turning screws which allowed reduced fuel consumption and slightly higher speeds than in previous classes, but at the expense of reduced maneuverability at low speeds.

With the appearance of the new dreadnought-type battleships and battlecruisers beginning in 1906, predreadnoughts such as Irresistible were outclassed; however, they still performed some front-line duties during the early part of the First World War.