Good to still have you here Ronald! You are like the Chuck Norris of Dutch cat sailors to me, there's no stopping you.

As a pastor I do happen to believe in divine intervention, but I also believe in physics. I'd say the board probably got caught square to the current as it was flogging around and that eventually tore the strap.
The buoys out here have 30ft wakes 2x a day and I'd almost swear I saw a rooster tail on one... My bet is that the current which almost killed you paradoxically also saved your life. That and your fighting mentality. Hang in there man!