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Thread: Leak at CB trunk to keel joint

  1. #1
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    Default Leak at CB trunk to keel joint

    Well, as some of you may know, I launched my Ilur dinghy last fall and there was some water ingress. I assumed it was at the CB trunk/keelson join and now I know this to be true.

    The case logs are epoxied and screwed to the keelson. After the interior was built, I flipped the boat upside-down and saw that the joint wasn't perfect. I troweled epoxy in there and, for good measure put a 2" strip of glass over the joint. I thought that would do it. Wrong!

    Today I took out the board and added water to the inside of the boat with a hose to see exactly where the leak was. Bad news, it's in several spots on both Port and Starboard, mostly port. It comes in at the join under the 'glass. Orange arrow in photo.

    Right now, I'm thinking to dry it out, use a heat gun and get rid of the glass, then add more epoxy at the join and test again.

    Any advice?

    Signed,

    Wicked bummed in RI.

    drips.jpg

    slot.jpg

    Inkedslot2_LI.jpg

  2. #2
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    Default Re: Leak at CB trunk to keel joint

    Having dried it out completely, you might be better taking off the brass strip and then drilling in to intercept the crack/void. Then pump in your sealant, whether thickened epoxy or some other pumpable goop until it squeezes out of the leak path.
    It really is quite difficult to build an ugly wooden boat.

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  3. #3
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    Default Re: Leak at CB trunk to keel joint

    A fellow in our area had the same issue and their method for finding the leak sounded interesting. Instead of water, they used acetone to reveal the path. According to him, this helped the subsequent epoxy follow the channel, being thinned on the way.

    I've never done it myself though...

  4. #4
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    Default Re: Leak at CB trunk to keel joint

    wuts that black goo and brassy thing doin in the way down there ?
    A little bit of epoxy is a bad thing...use a lot !

  5. #5
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    Default Re: Leak at CB trunk to keel joint

    I don't know how your trunk/keelson joint is done, but if it's anywhere similar to the way I built my Somes Sound with the completed trunk fully bedded in epoxy onto the keelson, I wouldn't trust trying to fix it from the outside. To be certain of a leak free boat, I would cut the trunk out, clean up the joint, then reinstall. Yes, that is a big job and you'll end up having to remake the bottom section of the trunk. But trying to inject epoxy is dicey. Very likely you won't fill all the voids. Maybe some of those voids will be open to the sea but not to the interior of the boat. So you'll never see water but it will be slowly saturating the keelson/keel/garboards....

    Jeff

  6. #6
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    Default Re: Leak at CB trunk to keel joint

    Yes, Jeff, that is how it's put together, and you've just describe my worst nightmare! Like Bruce said above I should have used a sh!t-ton of epoxy for the assembly.
    I thought I used a lot, but probably should have used twice as much, letting lots squeeze out.

    Oddly, I am intrigued by the acetone then epoxy approach described by Andrew. I need to think.

    Cutting out the trunk would be very difficult, since access is limited by carlins and floors.

    Thanks for all the help so far.

    Mike

  7. #7
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    Default Re: Leak at CB trunk to keel joint

    Mike--bummer! Sorry to hear about the leak.

    Perhaps Francois would be worth consulting about how to deal with it?

    Tom
    You don't have to be prepared as long as you're willing to suffer the consequences.

    www.tompamperin.com

  8. #8
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    Default Re: Leak at CB trunk to keel joint

    I'm wondering if, as a first step, I should just get lots of neat epoxy slathered over the 'glass tape, followed by slightly silica-thickened epoxy.

    Like, lots of epoxy, but still letting the board clear. Seems like even if the interior of the joint is not perfect, if I keep the water out, I might be OK?

  9. #9
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    Default Re: Leak at CB trunk to keel joint

    Quote Originally Posted by Michael_Owen View Post
    I'm wondering if, as a first step, I should just get lots of neat epoxy slathered over the 'glass tape, followed by slightly silica-thickened epoxy.

    Like, lots of epoxy, but still letting the board clear. Seems like even if the interior of the joint is not perfect, if I keep the water out, I might be OK?
    If you are looking for a quick temporary fix that can be done right at a later date, sand the slot clean where it is leaking and laminate on a couple of layers of cloth in epoxy.
    If the joint is moving at all a thin coat of epoxy will crack.
    It really is quite difficult to build an ugly wooden boat.

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  10. #10
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    Default Re: Leak at CB trunk to keel joint

    So here's an idea, maybe its a bit off the wall.

    Remove the rub strips, and then using a router, route out the keel, cutting down into the CB case, taking a cut that's perhaps an inch wide, or may just a bit less than case itself. Essentially widening the CB slot, but only enough depth to get maybe half an inch or an inch in to the case itself, and not the full width of the bottom of the case.

    Now, fill the newly created void with fresh lumber, well attached with copious amounts of thickened epoxy.

    This give you an entirely new joint and a new opportunity to create a water tight joint.


    Gonna be a tricky bit of routering. Maybe better done with a mallet and chisel.





    This has been your harebrained suggestion for the day.
    There's the plan, then there's what actually happens.

    Ben Sebens, RN

    15' Welsford Navigator Inconceivable
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  11. #11
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    Default Re: Leak at CB trunk to keel joint

    Quote Originally Posted by BBSebens View Post
    So here's an idea, maybe its a bit off the wall.

    Remove the rub strips, and then using a router, route out the keel, cutting down into the CB case, taking a cut that's perhaps an inch wide, or may just a bit less than case itself. Essentially widening the CB slot, but only enough depth to get maybe half an inch or an inch in to the case itself, and not the full width of the bottom of the case.

    Now, fill the newly created void with fresh lumber, well attached with copious amounts of thickened epoxy.

    This give you an entirely new joint and a new opportunity to create a water tight joint.


    Gonna be a tricky bit of routering. Maybe better done with a mallet and chisel.





    This has been your harebrained suggestion for the day.
    oh , this is a good idea.

  12. #12
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    Default Re: Leak at CB trunk to keel joint

    Seconded!
    Steve

    If you would have a good boat, be a good guy when you build her - honest, careful, patient, strong.
    H.A. Calahan

  13. #13
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    Default Re: Leak at CB trunk to keel joint

    Quote Originally Posted by BBSebens View Post
    So here's an idea, maybe its a bit off the wall.

    Remove the rub strips, and then using a router, route out the keel, cutting down into the CB case, taking a cut that's perhaps an inch wide, or may just a bit less than case itself. Essentially widening the CB slot, but only enough depth to get maybe half an inch or an inch in to the case itself, and not the full width of the bottom of the case.

    Now, fill the newly created void with fresh lumber, well attached with copious amounts of thickened epoxy.

    This give you an entirely new joint and a new opportunity to create a water tight joint.
    Gonna be a tricky bit of routering. Maybe better done with a mallet and chisel.
    This has been your harebrained suggestion for the day.
    There must also be a need to get a good fillet inside the boat around the case logs - the other end of the leak.
    The strip of glass tape inside the case looks barely wet out. Probably just as well, because if it had been done properly, it would have trapped any water getting into that joint from the inside - it's probably a good thing this had happened, in a bad way
    The OP needs to be slathering a LOT more epoxy around, don't be shy with that stuff! It helps if you have some other small job ready to glue up with any left overs, if you're worried about waste.

    Pete
    I have seven trolls on ignore

  14. #14
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    Default Re: Leak at CB trunk to keel joint

    My thinking now is to remove brass strip and scrape sealant off, rough up the inside of the slot to above the glass strip, then layer lots of epoxy on, starting with neat and then hot-coating with thicker stuff, hopefully really sealing it from the outside.

    Then following Nick's advice from post 2, but with gravity on my side, get in to the boat, drill a bunch of 1/4" holes down through the bed logs to about 1/8" into the keelson, then drizzle thinned (10% with acetone) epoxy into these holes, maybe using gentle heat gun setting to encourage flow into any voids.

    Does this sound feasible?

    Thanks for your help!

    Mike

  15. #15
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    Default Re: Leak at CB trunk to keel joint

    Quote Originally Posted by Michael_Owen View Post
    My thinking now is to remove brass strip and scrape sealant off, rough up the inside of the slot to above the glass strip, then layer lots of epoxy on, starting with neat and then hot-coating with thicker stuff, hopefully really sealing it from the outside.

    Then following Nick's advice from post 2, but with gravity on my side, get in to the boat, drill a bunch of 1/4" holes down through the bed logs to about 1/8" into the keelson, then drizzle thinned (10% with acetone) epoxy into these holes, maybe using gentle heat gun setting to encourage flow into any voids.

    Does this sound feasible?

    Thanks for your help!

    Mike
    You are doing it in the wrong order. Pump the epoxy in first so that it squeezes out of the leak path. Then you know that you have filled all of the leak paths. Your way will trap air bubbles in the remote corners. Does not high temp sett of the epoxy quicker?
    If you can get refillable mastic tubes they should be able to pump the epoxy into the voids.
    It really is quite difficult to build an ugly wooden boat.

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  16. #16
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    Default Re: Leak at CB trunk to keel joint

    I had the same thought as Nick about order of operations. Instead of thinning the epoxy with acetone and then applying heat I would just warm the resin to lower the viscosity.

  17. #17
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    Default Re: Leak at CB trunk to keel joint

    OK, this makes sense. I'll remove the fiberglass tape, which was ineffectual anyway, clean up the area, then introduce the epoxy from above, looking for squeeze-out or dripping out. Then, when that process is complete, seal from below.

    I have re-fillable pastry bags. Maybe they can help pump in the resin.

    I'm trying not to despair. I have visions of plugging the CB slot completely and asking M. Vivier to design some lee-boards. Do not want!

    Thanks,

    Mike

  18. #18
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    Default Re: Leak at CB trunk to keel joint

    Mike
    I had good luck using an emptied and cleaned out elmers glue bottle to get epoxy into a long crack.
    Might work for you filling those drilled holes too.
    Good luck with the fix.

  19. #19
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    Default Re: Leak at CB trunk to keel joint

    This might be just the ticket for you.... Large syringes.

    https://www.amazon.com/Frienda-Scien...025692&sr=8-52
    I swear I'm half done.

  20. #20
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    Default Re: Leak at CB trunk to keel joint

    I might get some squeeze bottles from the beauty supply place if they are open this week.

    Just a shout out to Ben Sebens for his not-so-hare-brained suggestion. I may just give this a try. Maybe a very shallow cut 1/8" with the router, then the afore-mentioned drill and fill from above, then fix the routered area of the joint. Any reason not to just fill the routered out bit with thick epoxy and hold in place with peel-ply?

    By the way, I got half of the glass strip out today, and it really did not have enough resin. I don't know what I did. I thought I wet it out and filled the weave. Guess I was wrong. AND there was fairing compound trying to fill in the uneven bits. That probably didn't help.

    cb slt.jpg

    glass.jpg

  21. #21
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    Default Re: Leak at CB trunk to keel joint

    Personally I’d be reglassing Micheal. Not sure that epoxy on its own wouldn’t recrack with such a high stress area that is subject to movement. Maybe two layers of glass and I’d be finishing with a graphite layer to aid the board movement.
    my 2c

  22. #22
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    Default Re: Leak at CB trunk to keel joint

    Alrighty. It's been over a month since I presented this problem here and I've been (slowly) trying to put some of the good advice to use.

    I started by using a router and managed to remove between 1/16 and 1/8 inch of wood on both sides, but not all the way up to the joint. I can't get a 2" bit with a 1/4" shank for my little palm router, plus it was a bit sketchy working over my head in a narrow slot with a tool that can remove a lot of wood in a heartbeat.

    So I've been using chisels, rasps, even a grinder. The plan is to expose the joint, removing a bit of material below and above it, trowel neat and then thickened epoxy into the crack and basically all over the area, then set in a pre-wet sandwich of 2 layers of 'glass tape, wait 'till it gets tacky, but still green, roll on more goop slightly thickened, then peel-ply.

    Here's the scene as it is today. There's a Shop-vac in the boat.

    unnamed.jpg

    unnamed-1.jpg

    unnamed-2.jpg

    unnamed-3.jpg

    In the last photo, you can see the first of several holes that will be drilled down through the bedlogs to the joint. I will be pouring acetone in these holes to see if it comes out before any glassing or epoxy down below. If it comes out, i will follow with epoxy. Later, I'll plug these holes with dowels set in epoxy.

    Then last thing is to sand and scrape the joint in the interior and make a biggish fillet to seal from above. I'll try to keep the spaces under frames somewhat free for water to move back and forth, but I do want to get in there with at least some thick epoxy.

    I WILL GET THIS BOAT SAILING!

    Cheers,

    MIke

  23. #23
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    Default Re: Leak at CB trunk to keel joint

    To get epoxy or other adhesives into cracks a good method is to puddle it above the crack and use a shop vac underneath to pull it in. I have done this by making a masking tape “bowl” around the crack or hole and use a wand attachment to draw the epoxy through the crack.

  24. #24
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    Default Re: Leak at CB trunk to keel joint

    My cousin and I built a small silboat in 1963, the CB trunk leaked from almost the start. It was sailed extensively by several related families till I reclaimed it and rebuilt the trunk in 2013. She's still sailing with a new family.

  25. #25
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    Default Re: Leak at CB trunk to keel joint

    West System advertises that they formulated G/Flex for a variety of hard to glue joints and areas with wood that is either oily, slick, wet or just plain impossible. I should think that your CB trunk is one of those classic problems that it can fix!
    Jay

  26. #26
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    Default Re: Leak at CB trunk to keel joint

    Would it be uncool to ask how things are going?

  27. #27
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    Default Re: Leak at CB trunk to keel joint

    Not uncool at all, Dr. B. I got the port side from below done last week, and am doing the stbd. side today. It ended up being just layers of epoxy of increasing thickened-ness along the joint. No 'glass.
    But it is thick. I used lots.

    Next, I'll make a good sized fillet along the joint on the inside, and make sure to focus on the areas where frames intersect the bedlogs.

    Fingers crossed!

    Mike

  28. #28
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    Default Re: Leak at CB trunk to keel joint

    I also used the time with the boat off the trailer to get rid of the rear and middle rollers and replace them with HDPE strips. The rollers were really a pain when trying to get the boat back onto the trailer at the ramp, especially if there was wind or waves. (Almost always.)

    Hope that this makes that process easier!

    trailer.jpg

  29. #29
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    Default Re: Leak at CB trunk to keel joint

    Sweet, thanks. Wishing you continued success & looking forward to results. Whatever happens, know you've made a beautiful boat and that the leak will get repaired.

  30. #30
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    Default Re: Leak at CB trunk to keel joint

    Thank you!!! It certainly was a bit of a gut-punch finally finishing her and then finding this big problem right in the hardest to get at spot.

    And it continues to be an emotional roller coaster. The thick epoxy has made the slot narrower of course, and the board is not fitting. It was tight to begin with.

    So now I'm grinding the board down. I'm also sanding the thick epoxy a bit. I'll add one more coat of neat epoxy. maybe with graphite mixed in.


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