'Bruised for life' is how one young naval officer describes his short term of service. In 1980 he was one of the first intake of a trial three-and-a-half year commission. By the end of that period only three of the original 21 are still in the Royal Navy. What makes a young man want to train as a naval officer? Why did so many leave? Three who stayed the course, but left in October, confront these questions in a voyage of rediscovery on the River Dart - from Dartmouth, where it all started, until they could go no further.