Training: cut to HAS of sailors hoisting depth charges up on deck, ready to fire. Series of CUs showing Captain on bridge, a sailor with binoculars, the navigation officer at work. Cut back to sailor working on depth charges. Legend on his cap reads: "HMCS Saguenay". HAS of men manning torpedo launcher, training guns on Merchantmen. Intercuts to shots of freighters in convoy, of parts of camera ship, of water, of captain, crewmen carrying out various tasks, etc. Shots of men communicating with Aldis lamps.