On May 7, 1944 HMCS Valleyfield, a River-class frigate of the Royal Canadian Navy, was returning to St. John's, Newfoundland as part of an escort group. Just after midnight on May 7, U-boat 548 fired two acoustic torpedoes, at the five ships. One torpedo hit the port side boiler room on HMCS Valleyfield, splitting the ship in two. The ship sank within four minutes and because it was travelling astern of the group it took some time for the rest of the escorts to realize that HMCS Valleyfield had been sunk. Eventually HMCS Giffard returned to pick up survivors while the other members of the group HMCS Edmundston, HMCS Frontenac and HMCS Halifax searched unsuccessfully for the U-boat. Forty-three survivors were rescued from the water. Five of those rescued died later. One hundred and twenty-five (125) were lost.