Agreed. I spent some years in a manual wheelchair and I would not have gone on a pier, dock, boat or anything like that. At least wearing a flotation device, and not strapped to the chair, the person would have a chance. But those motorized chairs are unbelievably heavy---straight to the bottom.
My mobilized wheelchair is indeed heavy. But I'm still stunned by its nimbleness and quickness, even with my large 275lb. body in it.
You couldn't pay me to get anywhere near a boat or a body of water in this thing, however.
If you want a Google GMail account, FReepmail me.
Also, please see The Backside of American History
You'll love this 187 page .pdf (1.99 MB)