New Transom Leaking!!

[RANGER94]

Hello - I have been slowly working on replacing the transom on old aluminum boat at my family's lake house. It is pretty much 2 pieces wood sandwiching the aluminum back of the boat. I patched all of the holes in the aluminum with marine grade 5200, let that sit for several months. Then I placed the wood on both side of the aluminum, redrilled the holes to 1/2 inch and filled that with the marine grade 5200, and let that sit for a couple of months. I then redrilled the holes to 5/16, put stainless still bolts with washers on both sides, gooped the bolts & washers up pretty heavy with the 5200, tightened the bolts, and let that sit for 3 weeks.

After two years of off again, on again work (removing old paint, repainting etc....) today was my maiden voyage.

The bolts are leaking......

Any suggestions would be greatly appreciated. Otherwise - this boat is going to the scrapyard.

Thanks!

Ranger94

 

[Ail]

Are you sure it is the bolt holes is where the water is getting in? Did you do any leak tests after originally putting the bolts in?

I guess it is conceivable that the water is somehow getting in where you put the 5200 in the 1/2 inch holes. Drilling through the 5200 could have loosened it, and 2 years is a long time if exposed to different elements, expansion, contraction.

Just to be clear, this weekend was the first time you had it in the water in the two years since you put the transom in? Or did you mean it was the maiden voyage since you re-did the paint recently?

 

[great white]

Put it up on the trailer and fill it with water.

Its easier to see where the leak is coming out than in.

It might not be the bolts.

Unless you can actually see it coming in around the bolts.....

 

[RANGER94]

I am pretty confident the leak is from the bolts. The water is dripping directly underneath the bolts. This is the first time the boat has been in the water in two years. The boat has been stored in a basement. I put the bolts with the 5200 about 3 weeks ago. Should have used rubber or nylon washers on the outside where the transom hits the water? Should I remove the bolts and start over? That does not sound like fun with the 5200.

Thanks for the help so far.

 

[earl60446]

Why did you drill the holes to 1/2 inch, goop with 5200 then redrill again to 5/16 inch? I think your SS bolts are probably moving around in the hole some and this may be causing the leak.
Tim

 

[richg99]

I agree totally with Earl. I've heard of people drilling an over-sized hole ..and filling it with epoxy. I've never heard of using 3m5200 in place of the epoxy. I love 3m5200, but not in this instance.

If it were me, I'd pull the bolts out (might have to heat them)..drill the 1/2 inch holes out...and fill with epoxy. Then, do everything the way you have preciously done. Redrill the 5/16ths holes etc.

richg99

 

[Ail]

I agree the 5200, while a permanent seal, does not have the rigidity to drill through after curing and reliably hold the seal like epoxy does. On my temporary transom I fabricated last season and used for 2 months, I only drilled holes, put bolts through them and used stainless steel washers on both sides tightened until they drew in to the epoxy coat. I did not fill around the bolts with resin or 5200, and only one bolt leaked the first time out, after that no leaks for the rest of the time I had it on the water. In my experience two washers drawn tightly enough in to the transom should create a tight enough seal to prevent water from getting through one side or both.

If you are sure it is the bolt holes, then I would have to wager the 5200 through the 1/2 inch hole loosened after drilling through it, and perhaps the washers are not tightened enough to the transom, or seated completely flush against it. You can try rubber washers instead and see if that helps. Even with a small seam in the 5200 for the water to seep through, washers and a flat head bolt of some sort should create a tight enough seal. In my opinion based on limited experience.

 

[great white]

Ah, I missed the 5/16 bolt in a 1\2 hole.

I will agree with the others here. That is likely where your problem lays......