Comus-class corvette

HMS Curacoa at Sydney circa. 1890
Class overview
Name	Comus class
Operators	Royal Navy
Preceded by	Bacchante class
Succeeded by	Calypso class
Built	1876–1887
In commission	1879–1904
Completed	9
Scrapped	9
General characteristics
Displacement	2,380 tons
Length	225 ft (69 m)
Beam	44 ft (13 m)
Draught	19 ft (6 m)
Propulsion	Single screw driven by compound engines of 2,590 ihp ( MW)
Sail plan	Barque or ship rig
Speed	13.75 kt (25.5 km/h) powered; 14.75 kt (27.3 km/h)
Armament	(As built) Comus: 2 × 7-inch (178 mm) muzzle-loading rifles 4 × BL 6-inch (152 mm) 80-pounder guns 8 × 64-pounder (160 mm) muzzle-loading rifles 2 × light guns 8 × QF Nordenfelt guns 2 × torpedo carriages Curacoa to Constance: 2 × 7-inch muzzle-loading rifles 12 × 64-pounder muzzle-loading rifles 2 × light guns 8 × QF Nordenfelt guns 2 × torpedo carriages Canada & Cordelia: 10 × BL 6-inch (152 mm) Mk II guns 2 × light guns 6-10 × QF Nordenfelt guns 2 × torpedo carriages
Armour	Deck: 1.5 in (38 mm) over engines

The Comus class was a class of Royal Navy steam corvettes, re-classified as third-class cruisers in 1888. All were built between 1878 and 1881. The class exemplifies the transitional nature of the late Victorian navy. In design, materials, armament, and propulsion the class members resemble their wooden sailing antecedents, but blended with characteristics of the all-metal mastless steam cruisers which followed.

Despite their qualities they had relatively short commissions, as they soon were rendered superfluous by the "flood of warships" built under the Naval Defence Act of 1889. By the turn of the century all were in reserve, relegated to subsidiary duties, or being scrapped.

Purpose

Great Britain had a worldwide empire, founded upon and sustained by seaborne commerce. To protect this trade and police its empire, Britain constructed many small and medium-sized cruisers, the latter typically armed with guns up to six inches in calibre. They were designed to serve long periods at sea, and therefore were equipped with sails. The nine Comus-class corvettes and their later derivatives – the two Calypso-class corvettes – were ships of this type.

Design

Planning for six metal-hulled corvettes began in 1876. These vessels, which became the Comus-class corvettes, were designed by Nathaniel Barnaby. Among the Royal Navy’s last sailing corvettes, they supplemented an extensive sail rig with powerful engines. Unlike their French rivals, which built fast steamers and needed neither long range nor a full rig of sail, the Royal Navy required their cruisers to be capable of long voyages away from coaling stations. Their ships therefore had a beamy hull to handle their sails, making them slower under steam than their French counterparts.

The British vessels were similar in appearance and layout to the older wooden and composite-hulled small cruisers they were intended to replace, albeit larger and more powerfully armed. The vessels were among the first of the smaller cruisers to be given metal hulls, with frames of iron or steel. The forefoot was a ram forged from brass, a feature then in vogue. In common with older wooden vessels, their hulls had copper sheathing over timber beneath the waterline, but that timber simply served to separate the iron hull from the copper sheathing so as to prevent electrolytic corrosion. The timber extended to the upper deck; it was in two layers from the keel to 3 ft (.9 m) above the water line, and one layer above.

In an early case of a single builder taking responsibility for building an entire class, contracts for these first six vessels were all awarded to the John Elder & Company at Govan on the Clyde. They were all fitted with 3-cylinder compound engines, with one high-pressure cylinder of 46 inches diameter being flanked by two low-pressure cylinders of 64 inches diameter.

Two to three years later, the Admiralty ordered an additional three vessels to be built to the same design. Construction of these was awarded to the Royal Dockyards at Chatham and Portsmouth. This second group differed by carrying a barque rig instead of the ship rig of the first six ships. The compound engines in the new batch were of 4-cylinder type, with two high-pressure cylinders of 36 inches diameter and two low-pressure cylinders of 64 inches diameter.

Comus when built, showing ship rig

Diagrams of the Comus class

In the Comus class, the bow above the waterline was nearly straight, in contrast to that of wooden sailing ships. The corvettes had stern galleries, similar to older frigates, but the ports were false, and there were no quarter galleries. Boats were carried both amidships and at the stern. The ships flew a barque or ship rig of sail on three masts, including studding sails on fore and mainmasts. The masts were stayed by shrouds which were anchored to chainplates affixed to the inside of the gunwales, rather than the exterior as in wooden sailing ships. Their sailing rigs enabled them to serve in areas where coaling stations were rare, and to rely on their sails for propulsion.

The vessels had two complete decks, upper and lower, with partial decks at the forecastle and poop. The forecastle was used for the heads and working space for the cables. The poop deck contained cabins for the captain, first lieutenant, and navigating officer, with the double wheel sheltered under its forward end. Between these was the open quarterdeck on which the battery was located. Under the lower deck were spaces for water, provisions, coal, and magazines for shell and powder. Amidships were the engine and boiler rooms. These were covered by an armoured deck, 1.5 inches (38 mm) thick and approximately 100 ft (30 m) long. This armour was about 3 ft (90 cm) below the lower deck, and the space between could be used for additional coal bunkerage. The machinery spaces were flanked by coal bunkers, affording the machinery and magazines some protection from the sides. The lower deck was used for berthing of the ship's company; officers aft, warrant and petty officers forward, and ratings amidships, as was traditional. The tops of the coal bunkers, which projected above deck level, were used for seating at the mess tables. The living spaces were well-ventilated and an improvement over prior vessels.

There were some refinements in the design among class members, and the armament in particular changed during their careers. In 1881 an enlarged version of the design was drawn up by Barnaby, with the hull being lengthened by another 10 ft. Two ships were ordered to this later design, which became the Calypso class. The Comuses and Calypsos were sometimes called the "C class" of corvettes, an informal term rather than an official designation.

Armament

Comus was armed with two 7-inch muzzle-loading rifles, eight 64-pounder muzzle-loading rifles and four breech-loading 6-inch 80-pounder guns, but the breech loaders proved unsatisfactory. The rest of the class were provided with four more 64-pounders in place of the 6-inch breech loaders, except for Canada and Cordelia, which exchanged all the muzzle loaders for ten of the new 6-inch Mk II breech loading guns. A selection of light guns and Nordenfelt quick-firing guns, as well as a pair of torpedo carriages, were also carried. The large guns were in embrasures in the bulwarks of the upper deck; this was a common (and to some extent a differentiating) feature of steam corvettes, as most frigates carried their main armament one deck lower. The details of the main armament varied between the vessels, and during their careers, as all were rearmed after their first commissions.

Ships

Painting of Carysfort c. 1887

Ship	Laid down	Builder	Engine-builder	Launched	Completed	Disposition	Fate
Comus	17 August 1876	John Elder	John Elder	3 April 1878	23 October 1879	Struck 1902	Sold for breaking 1904
Curacoa	17 August 1876	John Elder	Humphrys, Tennant and Dykes	18 April 1878	24 February 1880	Seagoing tender	Sold for breaking 1904
Champion	17 August 1876	John Elder	John Elder	1 July 1878	7 December 1880	Stokers' training ship	Sold for breaking 1919
Cleopatra	17 August 1876	John Elder	Humphrys, Tennant and Dykes	1 August 1878	24 August 1880	Training ship; overflow hulk	Sold 1931, broken up 1933
Carysfort	17 August 1876	John Elder	John Elder	26 September 1878	15 September 1880	Paid off 1901	Sold for breaking 1899
Conquest	17 August 1876	John Elder	Humphrys, Tennant and Dykes	28 October 1878	18 April 1885	Paid off 1894	Sold for breaking 1899
Constance	14 September 1878	Chatham	John Penn and Son	9 June 1880	3 October 1882	In reserve 1889	Sold for breaking 1899
Canada	7 July 1879	Portsmouth	J. & G. Rennie	26 August 1881	1 May 1883	In reserve 1896	Sold for breaking ca. 1898
Cordelia	17 July 1879	Portsmouth	J. & G. Rennie	25 October 1881	25 January 1887	Paid off 1898, stricken 1902	Sold for breaking 1904

Sources

• Archibald, E.H.H.; Ray Woodward (ill.) (1971). The Metal Fighting Ship in the Royal Navy 1860-1970. New York: Arco Publishing Co. ISBN 0-668-02509-3.

• Brassey, T.A. (1896). The Naval Annual. Portsmouth: J. Griffin and Co.
• Colledge, J. J.; Warlow, Ben (2006) [1969]. Ships of the Royal Navy: The Complete Record of all Fighting Ships of the Royal Navy (Rev. ed.). London: Chatham Publishing. ISBN 978-1-86176-281-8.
• Lyon, David (1980). Steam, Steel and Torpedoes. Ipswich: W.S. Cowell, Ltd. for HM Stationery Office. p. 39. ISBN 0-11-290318-5.

• Osbon, G. A. (1963). "Passing of the steam and sail corvette: the Comus and Calliope classes". Mariner's Mirror. 49. London: Society for Nautical Research: 193–208. doi:10.1080/00253359.1963.10657732. ISSN 0025-3359.

• Paine, Lincoln P. (2000). Warships of the World to 1900. New York: Houghton Mifflin. ISBN 0-395-98414-9.

• Winfield, R.; Lyon, D. (2004). The Sail and Steam Navy List: All the Ships of the Royal Navy 1815–1889. London: Chatham Publishing. ISBN 978-1-86176-032-6.