HMVS Cerberus - Design

Design

Named for Cerberus, the three-headed guard dog of Hades from Greek mythology, Cerberus was the first of the 'breastwork monitors', which differed from previous ironclad warships by the fitting of a central superstructure containing rotating turrets. The ship was designed by Edward James Reed, Chief Constructor to the Royal Navy. Cerberus had one sister ship, HMS Magdala, and an additional five ships of similar design (HMS Abyssinia and the four Cyclops class monitors) were constructed for coastal defence around the British Empire. These seven vessels were unofficially referred to as the 'Monster class'.

The monitor was 225 feet (68.6 m) long, 45 feet 1 inch (13.7 m) wide, and with a draught of 15 feet 6 inches (4.7 m). Cerberus had a freeboard of 4 feet (1.2 m), while her breastwork extended 7 feet (2.1 m) above the deck, and was 112 feet (34 m) long. She had a standard ship's company of 12 officers and 84 sailors, with an additional 40 to man the ship in wartime. Cerberus had a maximum speed of 9.75 knots (18.06 km/h; 11.22 mph), with an economical speed of 6 knots (11 km/h; 6.9 mph).

Her twin screws were driven by two horizontal twin-cylinder, double-acting, simple steam engines made by Maudslay Son & Field. They had 43-inch (110 cm) bore, 27-inch (69 cm) stroke, and were provided with 30 psi (210 kPa) steam produced by five coal-fired boilers with 13 furnaces. The steam engines generated 1,369 indicated horsepower (1,021 kW) on trials and drove two propellers with a diameter of 12 feet (3.7 m) Cerberus was the first British warship to be solely steam-powered. The monitor had a bunkerage of 240 tons of coal; this would last just under five days at maximum speed (50 tons consumed per day), and ten days at economical speed (24 tons per day). The monitor was not suited to ocean travel.

The main armament was four 10-inch guns, mounted in two turrets. The four guns weighed 18 long tons (18 t) each, were muzzle-loaded, had to be withdrawn completely inside the turret to be reloaded, and could fire a 400-pound (180 kg) shell up to 4,000 yards (3,700 m) once every three minutes. The turrets were mounted fore and aft; each had a crew of 33, had a 270° field of fire, and had to be hand-cranked into position. The turrets were of a design created by Cowper Phipps Coles.

The ship had armour plating ranging from 6 to 8 inches (150 to 200 mm) in thickness for the waterline armoured belt on her hull, which was backed by 9 to 11 inches (230 to 280 mm) of teak. The citadel armour protecting the breastwork ranged in thickness from 8 to 9 inches (200 to 230 mm), and gun turrets had 10-inch (250 mm) faces and 9-inch (230 mm) sides. Cerberus was protected by an armored deck that was 1 to 1.25 inches (25 to 32 mm) thick. For added protection, Cerberus could take water into ballast tanks, decreasing her already low freeboard until only the turrets and breastwork were visible.

Cerberus and ships of her type were described by Admiral George Alexander Ballard as being like "full-armoured knights riding on donkeys, easy to avoid but bad to close with." Robert Gardiner, Roger Chesneau, and Eugene M. Kolesnik, the editors of Conway's All the World's Fighting Ships: 1860–1905, pointed out that " the beginnings of practical turret ship design in Britain, having no sail power and being fitted with fore and aft turrets with almost uninterrupted arcs of fire." When she entered service, the monitor was considered superior to any other warship operating in the Australasian region. The design of Cerberus was a major influence on battleship design until the early 1900s, when HMS Dreadnought made all pre-dreadnought battleship designs obsolete.