84- 20’ Overnighter Hull to Deck joint repair

[Sdgrady20]

Hello all:

I suspect I have a leak at the hull and deck joint on my port side bow. Looking for any information on how to effect a proper repair. Thanks for any info anyone can provide. SD

 

[DennisG01]

Verify, don't suspect. Use a hose in a systematic way to verify. But, to answer your question... the leak could be the cap joint or it could be through screws. Remove the rubrail and inspect. If you need to fix the cap joint, use wedges to separate the joint further. Use an oscillating tool with a scraper blade to remove as much of the old adhesive caulk as you can. Continue to use the wedges and use something like 3M5200 (this is one of the few applications for this stuff) squirted up into the gap. Pre-tape the area to make clean-up easier. Factories would have used a different brand/product, but 5200 is readily available and will work just as well. After about 6 or 10 feet (depending on the gap), keep reinserting the screws to pull the gap tight - a little 5200 on the threads is a good idea.

 

[PointedRose]

Verify, don't suspect. Use a hose in a systematic way to verify. But, to answer your question... the leak could be the cap joint or it could be through screws. Remove the rubrail and inspect. If you need to fix the cap joint, use wedges to separate the joint further. Use an oscillating tool with a scraper blade to remove as much of the old adhesive caulk as you can. Continue to use the wedges and use something like 3M5200 (this is one of the few applications for this stuff) squirted up into the gap. Pre-tape the area to make clean-up easier. Factories would have used a different brand/product, but 5200 is readily available and will work just as well. After about 6 or 10 feet (depending on the gap), keep reinserting the screws to pull the gap tight - a little 5200 on the threads is a good idea.

You may want to tape off the area to contain the gooey mess. Wear throwaway gloves. I think the best way to seal after what Dennis suggested is to let the 5200 set for 24 hours - then tighten screws all down tight. Allows the 5200 to gel, create a gasket, without squeezing it all out while wet. Totally agree though - you need to diagnose the point of leakage. If it’s screws that have come loose and enlarged a hole, you can refill with epoxy, let dry and redrill it

 

[Sdgrady20]

Dennis and PointedRose, thanks guys, makes total sense. Great info much appreciated.

 

[seasick]

Remove the rub rail as mentioned but before separating anything, take a look at the seam to see if was caulked. It may have been glued but it may not have been,
Remove the caulking as best as you can but don't separate the cap lip yet. Now for the hard part; You need to determine if the deck is firmly attached at the lip overlap. You can try prying the lip a bit to see if it flexes. If it is still attached firmly, I wouldn't use the wedges. I would first verify that the screws still bite well, by giving them a go with a screwdriver, possible removing them and inspecting.
If you are lucky, the deck connection to the hull may be fine and all you need to do is recaulk the seam and rebed the screws. Note that at that age, the screws may break off. If so, drill new holes ( counter sunk if the originals were), and rescrew with new screws, and adhesive like 5200.

All that said, you were well advised to see if you can locate the leak source. The first step is removing the rub rail but keep in mind that the now exposed rub rail screw holes may leak even though they didn't before.

 

[Sdgrady20]

More great info, thanks seasick!

 

[seasick]

My pleasure.
Let us know what you find.

 

[Sdgrady20]

Removed the rub rail and found the the caulking had pulled away from the hull and was allowing water in the joint. Removed the old caulking, cleaned up the joint and backed out the screws securing the deck to the hull at the joint to allow for the joint to open a bit. Caulked it with 5200 and am going to allow it to set overnight and then tighten the screws tomorrow. While I am at it I am going to replace the screws at the joint and the ones that hold the rub rail in place. Should be good to go back in the water for the weekend. Really was a fairly easy repair and the responses I got here helped me know what to expect! Thanks all!

 

[DennisG01]

Just an FYI, since you are allowing the 5200 to setup overnight and THEN tightening things up, you're not really going to get the gap to close much. Not a huge deal, but the rubrail likely won't fit as nicely against the hull. Ideally, retighten the screws right away to avoid the gap staying "big". If you go out and do it tonight, you should be OK as the 5200 is probably still soft enough.

 

[PointedRose]

Just an FYI, since you are allowing the 5200 to setup overnight and THEN tightening things up, you're not really going to get the gap to close much. Not a huge deal, but the rubrail likely won't fit as nicely against the hull. Ideally, retighten the screws right away to avoid the gap staying "big". If you go out and do it tonight, you should be OK as the 5200 is probably still soft enough.

Good point, although like you said it’ll stay soft for a while, I’ve found even beyond the 24 hours it says it’s supposed to dry, so as long as it’s not too thick when put on and done sooner than later it still should cinch down and seal nicely. You’ll probably see a little sealant seep out the edge when tightening down. Can trim any excess sealant with a utility knife.

 

[seasick]

Regular 5200 cures slowly, perhaps 24 to 48 hours before you should stress it. It can take a lot longer to fully cure especially for thicker uses. You probably will be able to tighten the screws for a while. If you haven't, you should also coat the screw threads with 5200. To do that, you will need to remove, squeeze in some 5200 and rescrew.

 

[DennisG01]

You guys are right about the curing time if it's NOT the fast cure stuff. I've never used the normal stuff as I never understood the reason to wait almost a full week for a full cure. I've only ever used the fast cure formula - and there have been many times (temp seems to play a role) where, while not fully cured, it is pretty darn solid after just half a day. Hopefully this won't be the case for sdgrady, though.

 

[seasick]

3M states that 5200 cures at about 1 mm or less per 24 hours. In that case, a 1/4 bead would fully cure in about a week

A similar application of 5200 Fast Cure will fully cure in about 2 1/5 to 3 days under similar conditions.

 

[DennisG01]

A similar application of 5200 Fast Cure will fully cure in about 2 1/5 to 3 days under similar conditions.

My real world experience with the stuff has been much different than what their numbers say! But "fully cured" is different than what, I think, we are really talking here - referring primarily just to the ability to still be squeezed out.

 

[Sdgrady20]

Hello all, thanks for your comments and the discussion. I finished caulking about 4 pm on tuesday and got out about 7 am this morning (Wed) and cinched down the screws. It came together nicely, as the 5200 was still pretty wet, with some bulging and oozing of the caulking. Plan on letting it set up till Friday and then will trim off the excess caulking. I hope that the 5200 will be set up enough by then to allow me to trim it without too much of a mess. But we will see what I run into on Friday and if I have to let it set up longer I will.