This is a very dangerous idea! Your ship is a sitting duck. As well, the original contact might not have been accurate. ASDIC is notorious for giving false readings due to old wrecks, thermoclines - or layers of water at different temperatures, or even whales or schools of fish. Stopping the ship leaves you further and further behind the convoy and leaves it short one escort ship. The escort commander sends you a sharply worded signal to get back on station!