This week I flew a 120 mile sea crossing (and back). I am not stupid, I wore an immersion suit, lifejacket, had floats fitted and carried a dinghy.
I would not have even considered it in a single engined helicopter, even if it was fitted with this magic engine that never fails. Yes, many other things could have brought me down, but I don't get paid enough to take that risk. I have over 1000 hours single turbine, 7000 total. My one single failure was over the English Channel with 60kt winds at 1000'. The second engine took me to Belgium. Only God knows how many of us would have survived a ditching.