Of all the various forces and divisions of air, land or sea, on both sides of the conflict, the U-boat posting had the greatest mortality rate of any in the Second World War. British planes dropped leaflets over Germany, warning potential new recruits that for every one of the 2,000 U-boatmen who were currently living as prisoners of war in Britain, five more had already been killed at sea. Life-insurance companies in neutral countries estimated the average life of a U-boat sailor to be fifty days.7 This was not the hyperbole
