Subpar Transom Repair - Thoughts?

[Blue_Heron]

There's one other thing to look out for. A thick inner laminate spreads the crushing/puncture loads from the engine mounting bolts. Your thin laminate won't, so either get large fender washers or plates to spread the load over a larger area.
Dave

[Bushwacker]

Originally Posted by Blue_Heron

There's one other thing to look out for. A thick inner laminate spreads the crushing/puncture loads from the engine mounting bolts. Your thin laminate won't, so either get large fender washers or plates to spread the load over a larger area.
Dave

You could also install some brass or SS sleeves in the holes for the engine mount bolts to help carry the crush loads.

Don's right about the I-beam concept for cored construction. Equal laminate thickness on each side of the core would create maximum stiffness, but I suspect most boat builders are inclined to cut corners and reduce cost on thickness of the inside laminate!

[FishStretcher]

Originally Posted by Blue_Heron

There's one other thing to look out for. A thick inner laminate spreads the crushing/puncture loads from the engine mounting bolts. Your thin laminate won't, so either get large fender washers or plates to spread the load over a larger area.
Dave

I suggest getting a couple of feet of 6061 aluminum C channel. Per ASTM B 308 with the rounded inside corners. I used 3 x 1.75". I put 2 feet down in the bilge. Use that as your "washer". It will transfer the load across to the box stringers. If you can handle the look, 3 feet of the same up in the splashwell will help spread the load there, too. With a little handiwork with a file and drill, you can use it as a cable trough for the outboard wiring harness and transom mounted depth sounder wiring harness.

To me, it makes more sense than trying to crush plywood under a fender washer that is distorting under the bolt load to become dome shaped.

I used this: http://www.mcmaster.com/#1630T321

[flyingfrizzle]

I have used 4" x 3/8" aluminum anodized flat bar before as a backing plate. It will look a bit better but not as strong as the channel would be. You can find this any where they builds t-tops. It is used for mounting t-top mount outrigger and for other support on boat towers ect. It would help spread the load much better than a fender washer or such.