The Alarm-class torpedo gunboat was the penultimate class of torpedo gunboat

Torpedo gunboat

In late 19th-century naval terminology, torpedo gunboats or, in north European usage, torpedo cruisers, were a form of gunboat armed with torpedoes and designed for hunting and destroying smaller torpedo boats...

 built for the Royal Navy

Royal Navy

The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

. The class was contemporary with the early torpedo boat destroyers

Havock class destroyer

The Havock class was a class of torpedo boat destroyer of the British Royal Navy. The two ships, and , built in London in 1893 by Yarrow & Company, were the first TBDs to be completed for the Royal Navy, although the equivalent pair from J.I...

, which were faster and better suited to accompanting the battlefleet. By World War I the class had either been sold, converted to submarine depot ships or minesweepers, or reduced to harbour service. Three of the class were lost during World War I while serving in the minesweeping role.

Design

The Alarm class was designed by Sir William White

William Henry White

Sir William Henry White was a prolific British warship designer and Chief Constructor at the Admiralty....

 in 1889 as an enlarged version of his previous Sharpshooter class

Sharpshooter class torpedo gunboat

The Sharpshooter-class torpedo gunboat was a class of torpedo gunboat built for the Royal Navy in the late 19th century. One of the class was hulked in 1904, seven were scrapped before World War I and five were converted to minesweepers...

. They had a length overall of 242 ft (73.8 m), a beam of 27 ft (8.2 m) and a displacement of 810 tons. They were engined with two sets of vertical triple-expansion steam engines, two locomotive-type boilers, and twin screws. This layout produced 3500 ihp, giving them a speed of 18.7 knots (36.6 km/h) with forced draught. They carried between 100 and 160 tons of coal and were manned by 91 sailors and officers.

Thornycroft Special - HMS Speedy

While officially classed with the Alarm class, the Speedy was actually a separate design. The Naval Defence Act of 1889

Naval Defence Act 1889

The Naval Defence Act 1889 was an Act of the Parliament of the United Kingdom, instituted on May 31, 1889 to increase the United Kingdom's naval strength and formally adopt the country’s "two-power standard." The standard called for the Royal Navy to maintain a number of battleships at least equal...

 authorised the purchase of an Alarm-class torpedo gunboat built to a design by John I. Thornycroft & Company

John I. Thornycroft & Company

John I. Thornycroft & Company Limited, usually known simply as Thornycroft was a British shipbuilding firm started by John Isaac Thornycroft in the 19th century.-History:...

 and built in their yard at Chiswick

Chiswick

Chiswick is a large suburb of west London, England and part of the London Borough of Hounslow. It is located on a meander of the River Thames, west of Charing Cross and is one of 35 major centres identified in the London Plan. It was historically an ancient parish in the county of Middlesex, with...

. Speedy was a three-funnelled vessel (compared to the two-funnelled Admiralty design), but the key difference was the use of water-tube boilers instead of locomotive-type boilers; she produced at least 5000 ihp and could make 20.5 knots (40.2 km/h). The use of water-tube boilers was a key feature of the new torpedo boat destoyers that would make torpedo gunboats (including the Alarm class) obsolete.

Armament

At build the class was fitted with two QF 4.7 inches (11.9 cm)/45-pdr guns

QF 4.7 inch Gun Mk I - IV

The QF 4.7 inch Gun Mks I, II, III, and IV were a family of United-Kingdom 120-mm naval and coast defence guns of 1888 and 1890s which served with the navies of various countries. They were also mounted on various wheeled carriages to provide the British Army with a long range gun...

, four 3-pdr guns and one Gardner machine gun

Gardner gun

The Gardner gun was an early type of mechanical machine gun. It had one or two barrels, was fed from a vertical magazine or hopper and was operated by a crank. When the crank was turned, a feed arm positioned a cartridge in the breech, the bolt closed and the weapon fired...

. Five 14 inches (355.6 mm) torpedo tubes were fitted in the first five vessels, but this was changed to three 18 inches (457.2 mm) torpedo tubes in the rest of the class. They were arranged as a pair of revolving deck mounts, a pair of fixed deck mounts (deleted in the later vessels) and a single bow-mounted tube; three reloads were provided.

Ships

Name	Ship Builder	Launched	Fate
	Naval Construction & Armament, Barrow	14 May 1892	Became a minesweeper in 1909. Sunk by a mine off the west coast of Scotland on 7 April 1917
	Sheerness Dockyard	14 June 1892	Became a minesweeper in 1909. Sold for breaking on 30 July 1920
	Sheerness Dockyard	15 June 1892	Became a minesweeper in 1909. Became a depot ship for submarines in 1910 (guns retained). Sold for breaking on 22 October 1919
	Laird Brothers, Birkenhead	7 September 1892	Became a depot ship for submarines in 1907 (armament removed). Renamed Vulcan II in June 1919 (or April 1920?). Sold for breaking in August 1924 and resold on 9 October 1924
	Sheerness Dockyard	13 September 1892	Became a minesweeper in 1909. Sold for breaking on 14 July 1920 and broken up in Germany in 1922
	Sheerness Dockyard	13 September 1892	Sold for breaking on 9 April 1907
	Naval Construction & Armament, Barrow	24 September 1892	Sold on 11 July 1905
	Laird Brothers, Birkenhead	6 December 1892	Sold for breaking on 4 April 1905
	Naval Construction & Armament, Barrow	17 December 1892	Became a minesweeper in 1909. Torpedoed by U-12 off Deal on 11 November 1914
	Thornycroft, Chiswick	18 May 1893	Became a minesweeper in 1909. Sunk by a mine off the Humber on 3 September 1914
	Devonport Dockyard	12 July 1893	Reduced to harbour service in 1910 and used as training ship at Devonport. Sold for breaking on 27 May 1919