Fairmile D "Dog Boats" as E-boat fighters

Admiralty and Fairmile cooperation produced the Fairmile D to take on E-boats and other German coastal craft directly. A representative fit combined a forward six-pounder, Oerlikon 20 mm cannon, machine guns, depth charges, Type 291U radar, and Type 244 identification equipment. Other versions carried a second six-pounder or different heavy weapons, so the class was not tied to one layout. At about 29 knots, the Dog Boat relied on a combination of mobility and unusually heavy firepower instead of pure speed. Different convoy and attack-gunboat fits also meant an enemy might not know which armament it faced until the engagement had closed.