Coastal Forces of the Royal Navy operated Motor Launches (ML), Motor Torpedo Boats (MTB) and Motor Gun Boats (MGB) during Second World War and after.
The vessels were made by several manufactures and the designs varied.
MTBs were intended for attacking enemy shipping while MGBs were armed for combat with other fast attack craft. Motor Launches were used for harbour defence and anti-submarine operations.
The Steam Gun Boats were a class of nine high speed vessels intended to combine the functions of an MTB and an MGB comparable to a German "E-boat". They were powered by steam turbine engines due to lack of suitable internal combustion engines. Only seven of the nine ordered out of a planned 52 boats were completed.
Operated as a single flotilla in the Channel, SGB7 was lost in the 1942 Dieppe Raid The five remaining were converted to minesweepers in 1944.