backing plate

[tlr426]

So I am going to be making some backing plates for my kicker motor bracket. My question is the surface on the inside of my hull is not a smooth finish with highs and lows. I was planning on going with a piece of 3/8 stainless because that's what I have laying around. But if the surface isn't smooth and the fact that the plate will have little to no flex in can this be an issue? Would I be better off to cut individual squares because of the surface finish? My plan was to bridge the two bolts vertically on each side of the bracket. I figured two long plates would work best. Any insight would be greatly appreciated.

[rolmops]

I would just go with one big oversized plate,leaving plenty of room around the bolt holes. On the stainless you should use big washers because stainless is quite soft as far as metal goes. When you tighten the bolts coming from the bracket you will probably see the stainless bending inward a bit .That will increase the contact surface so you really do not have to worry about uneven surfaces. As far as force is concerned,90% is downward so the only real problem that you have is that the weight of the outboard will enlarge the boltholes in the transom in a vertical way. Because of this,a big single plate with lots of surface contact (even it is uneven) will serve you the best.

[TileMan Dan]

You also sand the surface of the gel coat to smooth it down a bit to remove any high spots.

[tlr426]

Makes sense thank you

[Xxx]

I always thought with the stainless steel I ever worked with it was the hardest damn steel I ever worked with, shy of titanium. You won't bend 3/8 stainless with the bolts that hold on a motor bracket!!!! You will tear off grade 8 bolts before that plate will bend. I would cut 2""X length for each side to bridge your bolt pattern, from top to bottom. That will allow your variation from side to side.

[tlr426]

Pap I agree that with a 3/8 plate I am not bending it with 3/8 cariage bolts that hold the bracket in place. I will use the extra large washers on the back of the plate. Thanks again

[Chas0218]

haha I just used that synthetic decking you can get from lowes or homedepot. My cleats were originally backed with marine plywood so I figured this was a little bit of an upgrade from the plywood. Either way I haven't pulled a cleat off or downriggers. The downriggers are backed with 16" piece.

[tlr426]

I was thinking about using some marine plywood that I had laying around. Until I came across a nice piece of stainless