The Fairmile B motor launch (often abbreviated to 'ML') was a very numerous class of motor launch produced in kit form by British boatbuilder Fairmile Marine, and then assembled and fitted out by numerous boatyards during the Second World War to meet the Royal Navy's coastal operation requirements.
Design While the Type A motor launch had been designed entirely for Fairmile by architect Norman Hart, the Type B design had come from Bill Holt, head of the Admiralty's DNC Boat Section. The hard-chine hull of the Type A had exhibited seakeeping and handling limitations, but Holt's round-bilged design for the Type B was found to be a far more seaworthy form.
Like all Fairmile boats, production of the Type B was based on total prefabrication so individual components could be contracted out to small factories for production and these arranged as kits that would be delivered in stages to various boatyards for assembly & fitting out on a 'just-in-time' basis. Accordingly, the detailed design work for the Type B was taken on by Fairmile and modified to suit their kit fabrication principle - they then also handled production of component parts.
Altogether approximately 650 boats were built between 1940 and 1945. Like the Type As, the Type Bs were initially intended as submarine chasers, so the boats were fitted with ASDIC (sonar) as standard.
Their main armament initially reflected their anti-submarine focus, with 12 depth charges, a single QF 3-pounder Hotchkiss gun forward, and one set of twin 0.303-in Lewis or GO machine guns (frequently increased in number by the crew); early boats often received a Holman projector amidships. A common upgrade to gun armament by 1942–43 in many early boats was to add an aft bandstand mounting for either a 2-pdr Rolls gun or a 20mm Oerlikon cannon. The specifications given are for the original 1940 British version.
As the war moved on, the vessels were adapted to other roles and the armament was modified and upgraded such as the replacement of the 3-pounder with one or more 20 mm Oerlikon cannon and removal of the ASDIC dome for more clearance as minesweepers. Some boats were configured as motor torpedo boats.
Boats The Fairmile B type superseded the original Fairmile A type, which had been designed by Norman Hart.
First batch (September 1939 orders) An initial batch of 24 of these (ML 101 to ML 124) was ordered by the Admiralty as part of its first emergency war programme on 22 September 1939 from the Fairmile Marine company, of which the first eleven (plus the prototype ML 100) were completed to the Hart design (see Fairmile A motor launch); the remaining thirteen (ML 112 to ML 124) were completed to the new Fairmile B design. The first Fairmile B motor launch (actually ML 113 from Tough Bros, Teddington) was completed and delivered on 12 August 1940, with a further eleven from this first production batch entering service before the end of the year (the last of the batch to be completed - ML 123 - was delayed until 1941).Angus Konstam, British Motor Gun Boat 1939–45 Osprey Publishing Limited 2010, (p.15) NameShip BuilderCompletedFateML 112Woodnutt & Co., St Helens, Isle of Wight22 September 1940Sold on 27 February 1946.ML 113Tough Brothers, Teddington12 August 1940Sold in March 1946 as Pendennis.ML 114Brooke Marine, Oulton Broad, near Lowestoft24 August 1940For disposal in 1946.ML 115Solent Shipyard, Sareisbury Green, Hants.18 September 1940Sold in October 1946.ML 116A. M. Dickie & Sons, Tarbert, Argyllshire14 September 1940For disposal in April 1946.ML 117Lady Bee, Isleworth26 October 1940Sold in 1946, becoming yacht Savourna by 1959.ML 118Sussex Shipbuilding, Shoreham-by-Sea, Sussex7 October 1940Sold in 1946 as Marandis.ML 119Alexander Robertson, Sandbank.12 September 1940Lent to South African Navy 1945; for disposal later in 1945.ML 120Aldous Successors, The Shipyard, Brightlingsea8 October 1940Sold 1946 as Onetwenty.ML 121James A. Silver, Rosneath, Dunbartonshire12 September 1940Sold in Egypt ca. 1947.ML 122A. M. Dickie & Sons, Bangor, Gwynedd16 October 1940Lent to Royal Norwegian Navy from 13 December 1940 to 23 August 1941; for disposal in October 1945.ML 123Frank Curtis, Looe, CornwallMay 1941To Free French Navy as St Ronan from May 1941 to July 1942; sold 1946.ML 124A. M. Dickie & Sons, Tarbert, Argyllshire13 November 1940To Ship Target Trials in 1946; for disposal in October 1947.
Second batch (January 1940 orders) The Admiralty placed a massive order for a second batch of Fairmile Bs - 120 vessels in total - on 8 January 1940. These were numbered ML 125 to ML 244. Of these, 37 were delivered by the end of 1940, another 77 during the first half of 1941, and the last 6 during the second half of 1941.