3d vosper 73 foot motor model - Vosper 73 foot motor torpedo boat by De Espona

At 73 feet long they were considered small boats compared to longer designs such as the Fairmile Type D.

The design came about from a requirement that British Motor Torpedo Boats should be better able to fight small craft which was the job of Motor Gun Boats. To this end Vospers built on their existing 70 foot designs. The type I was introduced in 1943 and the Type II before the end of the Second World War.

The boats carried four 18-inch torpedo tubes as their major offensive armament along with 20mm Oerlikon cannon and some defensive armament (Vickers K machine guns)for protection against enemy aircraft.

The type II gave up two torpedo tubes but gained a 6-pounder gun which displaced the twin Oerlikon to the aft deck. This made it more capable of performing the Motor Gun Boat role.