# Sealing cap to hull?



## EvanHammer (Aug 14, 2015)

I get water forced through this joint - not a big deal in the cockpit but it shows up in the rear hatch so nothing in there will stay dry. 

I've pulled the rub rail off and removed all the old sealant, then resealed the joint as well as possible with 5200. Still leaked. Also caulked the entire joint from inside the hatch but I'm still getting water in there. I ran ~60 miles yesterday and had a quart of water sloshing around in the hatch when I got home.

Any ideas on how to best seal the joint? How hard is it to remove the cap and reinstall it? It's bugging me having to bail out the rear hatch and hang everything to dry after every trip.


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## Smackdaddy53 (Dec 31, 2012)

Are you sure water is not being forced in around the transom? That’s what finally made mine dry.


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## EvanHammer (Aug 14, 2015)

Smackdaddy53 said:


> Are you sure water is not being forced in around the transom? That’s what finally made mine dry.


You can open up the rear hatch while running and see the water forcing in along the joint. I can also spray the joint from inside the cockpit and see water come out a couple places when you spray directly on them.


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## Smackdaddy53 (Dec 31, 2012)

EvanHammer said:


> You can open up the rear hatch while running and see the water forcing in along the joint. I can also spray the joint from inside the cockpit and see water come out a couple places when you spray directly on them.


Then you didn’t seal it good enough. If you get a 100% seal it can’t possibly leak. I drilled 1/4” holes about every 3” along the cap behind the rubrail and injected 5200 in each one then ran a bead along the seam and let it cure then reinstalled the rubrail and sealed the lower lip with black silicone. I also sealed the voids around the cap to hull around the transom and have had zero water intrusion since.


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## sjrobin (Jul 13, 2015)

Good idea on the 1/4" holes three inches apart all the way around the cap then injected with 5200. But even with the three inch injection you may still miss spots and it is almost impossible to remove all the salt, sand, moisture in the joining surface without removing the cap. Even 5200 will not seal well over time if the joint is not clean. A lot of Gordon skiffs and others have cap to hull fitment problems. Skiffs with a lot of hours pounding through Texas chop will expose the problem.


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## EvanHammer (Aug 14, 2015)

Smackdaddy53 said:


> Then you didn’t seal it good enough. If you get a 100% seal it can’t possibly leak. I drilled 1/4” holes about every 3” along the cap behind the rubrail and injected 5200 in each one then ran a bead along the seam and let it cure then reinstalled the rubrail and sealed the lower lip with black silicone. I also sealed the voids around the cap to hull around the transom and have had zero water intrusion since.


I like the idea of drilling holes - thought we got it sealed up pretty well but it's compounded by a separate molded spray rail that also mounts there.


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## Smackdaddy53 (Dec 31, 2012)

EvanHammer said:


> I like the idea of drilling holes - thought we got it sealed up pretty well but it's compounded by a separate molded spray rail that also mounts there.


I have hull #10 Maverick HPX Tunnel and it looks like someone cut the cap edge off with a dull chisel and hammer. I hope they didn’t build all of them like that! There was at least a 1/4” gap all the way around and I think I used 4 big tubes of 5200 to fill it all in.


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## SomaliPirate (Feb 5, 2016)

Smackdaddy53 said:


> I have hull #10 Maverick HPX Tunnel and it looks like someone cut the cap edge off with a dull chisel and hammer. I hope they didn’t build all of them like that! There was at least a 1/4” gap all the way around and I think I used 4 big tubes of 5200 to fill it all in.


Apparently the same guy was doing the 17T's over on the other side of the shop too.


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## lemaymiami (Feb 9, 2007)

Actually have something to contribute on this topic... since I've owned an old Maverick that was less than well sealed between cap and hull...

After lots of different solutions I finally found something that works.... 5200 by itself rarely seals cap to hull joints very well since it sags away from where you need it and the gaps are usually a bit too large here or there... That is compounded by cap to hull joints that are through bolted every 15" the way older Mavericks were done (and then you have rubrail screws to contend with as well...).

The solution is something called "backer rod" which is actually meant for tile installations where the gaps are to big to caulk well. "Backer rod" is actually solid foam tubing that comes in several diameters (and is also used to seal joints when you have the old in the window room air conditioners... It's a soft, compressible foam that you can push into place with a putty knife (0r a small section of very thin plywood - or even a wooden paint stirrer..). 

Here's the routine I follow. I start by laying a bead of 5200 up into the joint then I follow that with the foam, shoving it as far up into the joint as possible, following the caulking. Once the backer rod is in place I then run a second bead of 5200 on top of it - very effectively sealing the joint.... Just before running that second bead I lay down a tape line to the hull just inside of the bottom of the rubrail.... After the second bead is in place I use a plastic spoon to clean up the caulk line - then pull the tape for a clean job (5200 is miserable stuff to work with - I like plastic gloves when working with it). Since 5200 comes in several colors I always use black to match the rubrail -and the finished seal is hard to detect... 

Hope this helps - "backer rod" is available at big box stores like Home Depot - if you know what they call it.. Until I knew the label I have a terrible time finding what I needed....


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## EvanHammer (Aug 14, 2015)

lemaymiami said:


> Actually have something to contribute on this topic... since I've owned an old Maverick that was less than well sealed between cap and hull...
> 
> After lots of different solutions I finally found something that works.... 5200 by itself rarely seals cap to hull joints very well since it sags away from where you need it and the gaps are usually a bit too large here or there... That is compounded by cap to hull joints that are through bolted every 15" the way older Mavericks were done (and then you have rubrail screws to contend with as well...).
> 
> ...


Thanks for the idea on the backer rod Bob!


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