Royal Navy escort trawlers

During WWI a great number of trawlers were requisitioned by Admiralty for escort and auxiliary duties. In order not to infringe on the supplies of fresh fish, Admiralty in 1916 decided to commence on a building program for escort trawlers, resulting in 120 Mersey-class, 300 Castle- and 160 Strath-class units being ordered.

Esc 14 Macbeth1941


Shakespearian-class escort trawler HMS Macbeth. IWM


By the end of 1918, no less than 365 had been delivered to Royal Navy, while 82 were cancelled and a further 133 completed for commercial owners. During the interwar years most of the naval trawlers were sold for fishing.


During the mid-1930s Royal Navy again began to plan a new generation of escort trawlers, with HMS Basset being completed as the prototype in 1935. She differed from ordinary trawlers in having less sheer, longer foc’sle and engine/boilers amidships. A further five followed of the class, of 163.5 ft length.

Based on HMS Basset, a further 197 vessels were ordered from a modified design of 164 ft, to be of the following classes:

Tree                            164 ft             20 ea

Dance                          164 ft             20 ea

Shakespearian              164 ft            12 ea

Isles                            164 ft             145 ea


In addition, another 70 escort trawlers were built in smaller numbers to other design in Britain, New Zealand, Portugal and Brazil:

Admiralty                   156 ft             3 ea

Portuguese                 139 ft             6 ea (wood)

148 ft             6 ea

Brazilian                     176 ft             6 ea

Castle                        134 ft            17 ea

Hills                           181 ft             8 ea

Fish                           162 ft             10 ea

Round Table               137 ft             8 ea

Military                      193 ft             9 ea


The vessels were fitted out for escort duties with anti-submarine weapons as well as for mine-sweeping, net-layers, harbour duties, etc.


Further files:


The Isle class and sisters

Acquisition and transfer

Conversions for commial use


Portuguese class