I was somewhat cautious in
that water that cold will kill very fast.

And you should be. A few springs ago here on the Chesapeake a guy went out
with his girlfriend on their 27 footer. The guy jumps in the water to wipe off
the bottom since the boat spent the winter in the water. He never came up.
S/V Express 30 "Ringmaster"
"No shirt, no skirt, full service"