Excellent - keep them coming Guys...
I knew he was on a boat of some sort, but for some reason had thought it to do with 'ground' (sea) support for aircraft using bombing ranges. I didn't realise that the RAF operated a RNLI type service.
He was there in at least 61 and 62 so may have been with you on the harbour trip Chiglet!
Apparently some of the training involved a helicopter dropping people into the water and everybody would have to swim back to shore as a 'sink or swim' endurance test. I'm not sure how true that is..... I know he never chose to swim recreationally in later life!