Alim Marine tunnel boat rebuild

Oh, 1/4" aluminum is what I have on hand for the tab, and I can weld the connection pretty easily

 

If you leave any gap between hinges, water will spurt out and up. Make them wider than 12" if you can fit them in there. You can only experiment, but when you say there is a small amount of water shooting up the leg, that sounds as though you can raise the stern without losing prop grip. Your turnbuckle can be adjusted to the point it becomes counter-productive, then back it off a bit

 

The hinge gap would be about 1/8-1/4" at most. Really don't have the space along there as I'd start to get close to the outboard turning area. Could make them 9" deep. That would increase the surface area. Already crossing a stake with 12" wide.