Reportedly he made a point of urinating over the side; it was a point of pride. With only a strand of wire or rope at shin level, it’s quite possible he simply fell in late one night while answering nature’s call. Good riddance.
When I was way younger I did a bit of yacht racing. Urinating over the stern on night watch was a common way to go. Now people use jack lines at night to attach themselves to the boat. I took a partial dip that way once night. Luckily I got hooked up on a back stay, as the only other guy on night watch with me was barely conscious himself. He didn’t even notice.