Dan
I learned a similar version as a boy in the Sea Scouts
The point was to tie it on a line thrown to you from a moving boat if you went overboard. You used one hand to hold on to the line as you were dragged along, and the other to tie the bowline around yourself. BUT, you had to insert only your finger tips to flip over the loop, not your entire hand, in case you didn't manage to detension the line with your other hand.... We used to practice ashore with a friend yanking on the line .... got quite a few bruised fingers till we got the hang of it
. I've been tying single handed ever since
