"Therefore with a life jacket and proper planning a water crossing is very safe.
Safer than IMC over mountains (or even over a major fog bank) or worse still both at night."
I think I know what you mean but the engine no more knows it is over fog, mountains or water.
The risk of engine failure in any situation is fortunately very small.
The survivability of water without protection from the cold (and a lifejacket most certainly does not count) or from impacting whatever you might impact in mountains or over fog is debatable.
Personally I think I would take mountains, fog then water unless I knew for sure someone would pull be out the water within three hours (if I was only wearing a life jacket) - and most of the year I wouldnt make it that long I suspect.
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All this noise about how safe it is to cross the channel is a little tedious, can we keep this succinct?"
Blindingly and obvious all seem to come to mind at the same time - we were having a debate about the pros and cons of life rafts and immersion suits. We know the chances of a ditching are very remote and we know there are other precautions you can take - it just so happened we were debating one particular aspect - thread drift yes, but that is how these threads sometimes go.