I hit a submerged log in the murky upper Fraser River a few years ago. Wasn't going faster than 35-40 mph . What can be a real problem is if the input shaft pulls clear of the the bearing leaving a big hole . Either 3 or more high cap bilge pums needed or stuff some rag from inside in the bearing hole to keep water from coming in. Luckily my trim and steering rams
kept the shaft in the bearing as well as saving the bellows from ripping.
Looks better here ,eh