So you want an aux for your SIB...
Whilst out in the bay this weekend noticed a guy messing about with one of these on his yacht tender. Motored over, got chatting and he kindly let me bolt it on my boat (Aerotec) to try out. Amazingly it worked, OK there was only a light breeze, but it powered along better than a pair of oars / paddles. Prop easily unbolts so, while not small, will store fairly flat. If mounted to one side, with outboard on, need to be mindful prop doesn't foul on sponson cones when turning.
In no way an equal substitute to a small aux. motor, but equally much better than nothing.