IO540,
The study which I remember only analysed events where there was sufficient evidence. Aircraft 'missing' over water did not feature in the stats.
Perhaps the point I was trying to make is that, to my mind, the chances are good that you will have time to evacuate the aircraft, and perhaps deploy an internally-carried raft. So, not carrying a raft on the grounds that 'you'll never be able to get it out' would be a false analysis.
I wonder if those flying with BRS approach this issue significantly differently?
Regarding whether lifejackets are 'useless' or not, I recommend anyone try being winched from the water under a big helo without a lifejacket on, to demonstrate that, even for those few seconds, they are utterly invaluable. Yes, you can bob around in smooth water for a while if you're a strong swimmer, but under strong downdraught with spray in your eyes and a winchman trying to get the harness on - you'd need to be superman.