With a length of 205 feet and 1200 ton displacement, their triple expansion engines, twin oil-fired Scotch boilers and triple-bladed screw gave them a maximum speed of 16 knots, but their success was due to an amazing range of 4,000 miles at 12 knots and a turning circle tighter than that of a U-boat, the smallest of any Allied warship. Specifications varied with time and theatre of operations, but typically a corvette at war's end was equipped with sophisticated sonar and radar, and armed with a four-inch gun and 'hedgehog' charge thrower forward, an oerlikon gun on each bridge wing, and a searchlight and porn-porn gun aft, but her main armament was the depthcharge, of which she carried from 40 to 80, fired from four throwers and two stern traps.

As famous and successful a Second World War creation as the Spitfire or the Jeep, the corvette played a leading role in the bitter battles around the vital North Atlantic convoys on which wartime Britain depended for her very life. Later, as the escort groups grew in numbers, armament and training, they gained the upper hand of the German U-boats, so that the hunters of the early war years became the hunted. However, throughout the long and bloody Battle of the Atlantic the heavily laden merchant ships and their valiant crews continued to pay the price for the all important Allied command of the sea. A single U-boat torpedo could convert a huge oil tanker into a pillar of flame or send a heavily laden ore carrier to the bottom in a matter of seconds.