I'm with rottweiler!
I also had the benefit of the best training in the military, including one on one training. Still can't swim! I also did the CSRO course at Mountbatten and became my unit's Combat Survival and Rescue officer. I too conducted drills in both pools and open water.
I now fly over the North Sea, and have done for most of the last 18 years. I complete my HUET training regularly, even though I don't actually look forward to it! I also did the STASS training some years ago before it was decided that we pilots were not worthy to have them!
Confidence in the drills and the equipment are by far the best thing. The ability to swim can lead to over confidence in what can be acheived when wearing an immersion suit and LSJ etc.
bondu