My memory was that you didn't break your back in a BRS deployed SR-22 because a good proportion of the landing impact is absorbed by the under-carriage.
Obviously that isn't going to happen on water - so the impact may be harder than when landing on land.
So congrats to the pilot for coming out of it with no injuries!
I'm surprised they were able to travel for 4hrs 15min and still be 35min away from a ship, but then it is a very big ocean!