Mersey-class trawler

The Mersey class was a class of Admiralty naval trawlers built for the Royal Navy (or other government institutions) prior to World War II. Admiralty meant they were built for military service as opposed to conversions of existing boats. The majority of the vessels were built to a standard design but a few included in the class were built differently.

Some were completed as fishing vessels rather than for military service. Many went on to be used in various roles during World War II.

Design
The Mersey-class trawlers were purpose-built to a standard Admiralty design intended for patrol, anti-submarine and minesweeping roles. HMT John Quilliam, delivered in June 1917, was the first of the standard completions.

Propulsion was a three cylinder triple expansion steam engine, powered from a single boiler, and delivering nominal 87 horsepower (600 indicated horsepower)

The smallest of the non-standard ships measured 36.8 m in length with a 6.71 m beam.

Armament

 * 1x QF 12-pounder 12 cwt naval gun: John Edmund, John Highland, John Jacobs, John Johnson, John Pasco, John Quilliam, John Welstead, John Yule, Richard Bulkeley, Richard Colliver, Robert Double, Robert Drummond, Samuel Jameson, Thomas Jarvis, Thomas Johns, Thomas Whipple, William Doak, William Honnor, William Inwood, William Jackson, William Johnson, William Ram
 * 1 × QF 12-pdr 12 cwt gun and mechanical minesweeping gear: Cornelius Buckley, William Abrahams, Andrew King, George Andrew, Henry Cramwell, Henry Ford, Isaac Chant, James Buchanan, Lewis Roatley, Michael Clements, Robert Barton, Robert Bookless, Thomas Atkinson, Thomas Bailey, Thomas Thresher, William Jones, William Rivers
 * 2 × QF 12-pdr 12 cwt gun and mechanical minesweeping gear: William Westenburgh
 * 1x QF 4-inch gun, 1 × QF 12-pounder 12 cwt, 1x depth-charge thrower (also known as "bomb thrower"): Fraser Eaves
 * 1 × QF 12-pdr 12 cwt gun, 1x depth-charge thrower: George Bligh, James Adams, John Ebbs, John Felton, John Jefferson, Lewes Reeves, Nicholas Dean, Samuel Dowden, Thomas Cornwall
 * 1x QF 6-pounder Hotchkiss: Richard Jewell
 * 1 × QF 4-inch gun: Thomas Jago

Ships of class
For the Mersey-class the HMT prefix meant "His Majesty’s Trawler" but HMT was also used for vessels taken into Sea Transport Service as transports ("Hired Military Transport", though often referred to as “His Majesty’s Troopship”) and His Majesty’s Tug,.

A further 44 vessels were ordered, but were cancelled before delivery.