Or even some form of training of swimming with a lifejacket on.
Far from as easy as it sounds. Life jackets are designed to keep the user on their back, with their head above water. Any attempt to swim "normaly" is seriously hindered as the jacket want's to tip you over on to your back. Not easy if your trying to head in a straight line to a life raft. For those that have difficulty swimming, to swim backwards would be even harder still.