A Game of Birds and Wolves: The Ingenious Young Women Whose Secret Board Game Helped Win World War II

by Simon Parkin

while diving. During the time it took for the depth charge to fall, the U-boat would have disappeared. The Hedgehog enabled the explosives to be hurled ahead, while the U-boat was still within ASDIC contact, and before it could turn and dive.18 In the months that followed the development of Raspberry, using information gleaned via debriefs, Roberts and the Wrens developed numerous other tactical manoeuvres to suit the expanding variety of wolfpack attacks. Most of these manoeuvres, which involved the escort ships performing different shapes and varieties of coordinated sweeps to find and hunt lurking U-boats, were given the memorable names of fruit and vegetables: ‘Pineapple’, ‘Gooseberry’, ‘Strawberry’, ‘Artichoke’ and a modification to the original manoeuvre, known as a ‘Half-Raspberry’. These new manoeuvres provided escort ships with the tactics needed to go on the offensive, hunting U-boats before they made an attack rather than, in the case of Raspberry, after a merchant ship had been lost. Some, such as ‘Umbrella’, explored what to do in the event of a battle with a German surface raider–a merchant ship that had been fitted with powerful guns–rather than a U-boat.