Two vessels, Basset and Mastiff, were built by Henry Robb, of Leith. The main difference between them was that Basset had coal-fired, and Mastiff had oil-fired, engines.1 With the onset of war, Bassett served as the prototype for a series of Admiralty trawlers, of which a total of 180 were built during the conflict using a variety of naming schemes. The first 20 vessels were ordered under the 1939 programme (the Tree class), 30 vessels under the 1939 War Emergency programme in two groups (20 Dance class, and 10 Shakespearian class), and a further 130 over the next four years (the Western Isles (or, simply, Isles) class).2
Four vessels were built for the Royal Canadian Navy at various yards;3 these ships had strengthened hulls to cope with pack ice conditions and were also known as the Fundy class.
A further 16 vessels were ordered from Canadian shipyards in the war years, also bearing Canadian names. These were for the Royal Navy, though eight of these were transferred on completion to the Royal Canadian Navy. These are usually referred to as Canadian Isles-class trawlers.4
A total of 50 vessels were ordered from Indian yards (including two for the Ceylon Government)5 though in the event more than half were cancelled.6 Twenty-two were completed during the war;7 another 25 were cancelled and four were destroyed before completion when invading Japanese forces in 1942 over-ran their shipyards in Burma.8 These vessels bore the names of Indian cities, but are variously referred to as Indian Basset class9 or Indian Isles class trawlers.10
Conway p65 ↩
Elliott p292-6 ↩
Elliott p350-1 ↩
Lenton, H.T.; Colledge, J.J. (1964). Warships of World War II. London: Ian Allan. p. 414. ↩
Elliott p404 ↩
Lenton, H.T.; Colledge, J.J (1964). British Warship Losses of World War II. London: Ian Allan. p. 38. ↩