While the Type A had been designed entirely by Fairmile, the Type B design had come from Bill Holt of the Admiralty based on the lines of a destroyer hull and the detailed design and production was taken on by Fairmile.
Like all their designs it 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 to various boatyards for assembly and fitting out.
Altogether approximately 650 boats were built between 1940 and 1945. Like the A Type, the B Type 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 Hotchkiss 3-pounder gun aft, and one set of twin 0.303-in machine guns. 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. Some boats were configured as motor torpedo boats.
The first Fairmile B motor launch was completed in September 1940, with a further 38 from the first two production batches entering service before the end of the year.
All boats were essentially the same, although they could be adapted to serve in several roles by the expedient of having pre-drilled rails on their decks spaced to allow the fitting of various types of armaments. Although their armament initially reflected their main anti-submarine mission, nine of them were fitted with 21 inch torpedo tubes taken from ex-US Town class destroyers; they formed the 2nd ML Flotilla tasked with anti-invasion duty, until the threat had passed. During the Siege of Malta (World War II), they were successfully employed as Minesweeper (ship)s, as the larger specialist craft were too vulnerable to air attack. A number served in the St Nazaire Raid as assault transports, but their light construction meant that they suffered heavily; twelve B motor launches were lost in the action, out of sixteen deployed. Many were later converted to rescue motor launches with small sickbays aft of the funnel, and several more were converted to use as War Department (United Kingdom) ambulance launches with larger sickbays.
Canada built eighty boats. These were built in thirteen different Shipyard to slightly different specifications and used as escort vessels. Eight of these (ML392-399) were built by Le Blanc for the Royal Navy. These eight boats were transferred under Lend-Lease to the US Navy, because US coastal protection had been depleted by transferring ships to the Royal Navy for convoy work. The US Navy used them as submarine chasers (SC1466-1473) until their forces could be built up. There are two surviving examples on the west coast of Canada serving as party charter vessels.
Four currently survive in the UK, two of which are in excellent condition. One is MV Western Lady III. Many others of the type are known to survive around the world, some still in commercial service as tourboats.
* Allied Coastal Forces of World War Two, Volume I : Fairmile designs and US Submarine Chasers - by John Lambert (naval historian) and Al Ross - 1990, ISBN 978-0-85177-519-7
* ""War at Sea - South African Maritime Operations during World War II : CJ Harris - 1991
*Fairmile "B" Class Launches Accessed 28 November 2007
* Fairmile Motor Launch at Juno Beach Centre "Canada In WWII" junobeach.org
* Canadian Fairmile Q105 presently under restoration
* Fairmile B motor launch
* A Fairmile Submarine Chaser (photo of Fairmile B motor launch)
* Book on New-Zealand built Fairmiles used in New Zealand and the Solomons
* The Fairmiles, Canada"s Little Ships by Spud Roscoe
* Stoker Harold Siddall Royal Navy, his service in ML.1030 and capture in Crete 1941 at naval-history.net
* Pictures of Fairmile models
* List of books at PT-boats.com
* Little ships
* Fairmile Radio Fit by Jerry Proc
*Canada"s Little Ships by Spud RoscoeCategory:Gunboats of the Royal Navy