I sure hope that rig doesnt go very fast (looks like it won’t) because if he hits a submerged object, that motor is coming in the boat with him! Never a good idea to restrain the travel of the engine upward so the shocks can control the inertia. At least it doesn’t have trim on the motor.
Certainly not someone with any engineering logic. I’m good with the re purposing the boat to have an outboard but maybe just put a 9.9 on it to push it where you want to go/test out the theory. Wider wood blocks and 4 bolts comes to mind as well.