How I Reinforced My Transom

[maintenanceguy]

I bought an older PolarKraft 1754 jon boat with a 40 hp outboard. I bought it last fall with the plan to do some rebuilding/upgrading over the winter.

When I bought it, I could see that the transom had been replaced at some point. There is an obvious weld around the entire transom that is fine but doesn't look like it came from the factory. The center support bracket for the transom was cracked and somebody had hacked in a bunch of steel to reinforce the reinforcing bracket. The reinforcement for the cracked bracket wasn't done very well and really didn't do much to fix things.

They guy I bought it from was using the boat right up until he sold it so I think everything was probably fine without needing any work but I didn't want to take any chances. So, this is what I came up with:

Letters from the photo:
(A) a piece of 2" x 3" 1/8" wall rectangular stainless tube. I cut the ends at 21º to match the sides of the boat.
(B) 1/4" x 2" stainless flat stock welded to the beveled ends of the tube and drilled for bolts.
(C) a piece of 1/4" thick aluminum plate. I debated whether to remove the old cracked bracket to avoid notching this plate but decided to leave it and notch the plate around the old bracket. The plate is bolted to the transom.
(D) 3/8" stainless threaded rod with washer and nuts to anchor the transom to the 2x3 tube.

 

[lckstckn2smknbrls]

Do you have any pictures of the cracked knee brace? I lot of older StarCraft boats crack their knee braces and are repaired with pieces of thick aluminum angle bolted or riveted in.

 

[maintenanceguy]

I could have fabricated a new knee brace but didn't want to mess with floor since that part stays underwater. I would have had to weld, rivet, or bolt through the floor. It doesn't leak now and I'm not sure I can guarantee it would stay that way if I started messing with it.

I also don't really like that a single knee brace is pulling up on only 6 rivets in a concentrated area of the floor. The original brace cracked. I don't want to duplicate what didn't work. I'm sure that reinforcing the brace would have been adequate. In fact, it seems to have worked for years the way it is. But if you're going to fix it, go big or go home!