After the ferry SS Caribou was sunk by a U-boat in October 1942 with a loss of 137, including many women and children, the navy provided escorts to ensure the safety of passengers. Near the end of the war, HMCS Shawinigan was in Cabot Strait off Newfoundland. The corvette was not new to escort duty. Commissioned in late 1941, Shawinigan spent two years escorting convoys back and forth across the Atlantic. In 1944, it began escort duty in home waters, seeing East Coast ferries safely to and from port and patrolling for submarines. U-boats had been a danger in the Gulf of Saint Lawrence since 1942. “The Royal Canadian Navy established a routine of patrolling the Maritime coasts, but could not prevent the loss of 15 merchant and naval vessels,” wrote Gordon Laco in The Search for the HM...