My wife's family has had a ton of Goldens. One of them apparently didn't want to swim at the start. Her father had the bright idea to tie its collar to their other golden at the time. Threw a toy into the water and naturally the one that knew how to swim ran in to fetch it and yanked the other one in with him. The one that didn't "know" how to swim proceeded to attempt to sit on the other to stay afloat and almost drowned the poor pooch. Thankfully my father in law did manage to rescue them, but I don't think he tried that again.