I Had a similar mishap that occurred as a co-angler at a BFL on lake Eufaula, OK. Thankfully, the boat was slowing down preparing to go under a bridge in a idle only area. The entire engine broke off the jack plate and we did a 180. No one was hurt or thrown out but it was a scary deal. Here are a couple of pics : one with the motor off in the lake hanging by the fuel lines and the other at the ramp where we were towed.
Be safe out there. Things happen.