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Thread: Repairing keel separation

  1. #1
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    Default Repairing keel separation

    My plan was to attempt to fill this with epoxy and glass mixture but interested in any other opinions. This is an eun na mara 3BF61284-9D3A-4477-AA00-E837898A632D.jpg

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    Default Re: Repairing keel separation

    Hi Skerry,
    Is there glass already on there? And how long has she been out of the water? If it's really dry I'd worry that filling that with uncompressible bog and then launching and swelling the wood will just chase the crack further along the seam.

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    Default Re: Repairing keel separation

    Quote Originally Posted by Hugh MacD View Post
    Hi Skerry,
    Is there glass already on there? And how long has she been out of the water? If it's really dry I'd worry that filling that with uncompressible bog and then launching and swelling the wood will just chase the crack further along the seam.
    I don't believe there is glass. She was out of the water for 3 years but we sailed yesterday for two hours. I plan to put her in a slip once we find one but was worried about the crack leading to rot. It is supposed to be Purple Heart. Another item I heard is bolting it to tighten but I'm not sure where to start with that as I've never seen it done.

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    Default Re: Repairing keel separation

    Is the deadwood/keel built of small laminations or a few big nogs of wood?
    She is an epoxy boat overall , right?
    glue lap ply or strip built?

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    Default Re: Repairing keel separation

    Hi. I'm not an expert myself but i have some experience and my dad is a wooden boat builder. And he always told me to never try to fix a hole in a wooden boat with epoxy but do it properly. the epoxy might either be in the way when it swells it might trap water or it might dry more then pull the bits of wood together and make a gap somewhere else. he always told me that wooden boats live and move every part of a wooden boat shrinks and expands adding something that doesn't allow that in any direction might cause problems. Epoxy could also trap water and be a cause of rot later on in the life of the boat. in my not very expert opinion i would try and fix it without epoxy or fiberglass.

    What ever you decide i wish you all the best . And again I am not personally not an expert just saying what I have heard.

    Kind regards.

    David.

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    Default Re: Repairing keel separation

    Quote Originally Posted by wizbang 13 View Post
    Is the deadwood/keel built of small laminations or a few big nogs of wood?
    She is an epoxy boat overall , right?
    glue lap ply or strip built?
    Glue ply, epoxied yes

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    Default Re: Repairing keel separation

    Quote Originally Posted by wizbang 13 View Post
    Is the deadwood/keel built of small laminations or a few big nogs of wood?
    She is an epoxy boat overall , right?
    glue lap ply or strip built?
    Big nogs of wood

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    Default Re: Repairing keel separation

    Quote Originally Posted by dave2700 View Post
    Hi. I'm not an expert myself but i have some experience and my dad is a wooden boat builder. And he always told me to never try to fix a hole in a wooden boat with epoxy but do it properly. the epoxy might either be in the way when it swells it might trap water or it might dry more then pull the bits of wood together and make a gap somewhere else. he always told me that wooden boats live and move every part of a wooden boat shrinks and expands adding something that doesn't allow that in any direction might cause problems. Epoxy could also trap water and be a cause of rot later on in the life of the boat. in my not very expert opinion i would try and fix it without epoxy or fiberglass.

    What ever you decide i wish you all the best . And again I am not personally not an expert just saying what I have heard.

    Kind regards.

    David.
    Yes I'm rethinking now the epoxy solution, glad I asked.

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    Default Re: Repairing keel separation

    If the boat is not leaking, I might just put a wrench on the bolts for a feel. Too loose? crazy tight? Evenly cranked down?
    The "big nogs of wood" speak to the instability of the keel structure married to a modern monoquack construction.
    b

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    Default Re: Repairing keel separation

    Quote Originally Posted by wizbang 13 View Post
    If the boat is not leaking, I might just put a wrench on the bolts for a feel. Too loose? crazy tight? Evenly cranked down?
    The "big nogs of wood" speak to the instability of the keel structure married to a modern monoquack construction.
    b
    I'll give that a try, I'm still learning about this design and construction so I wasn't aware they were adjustable. Thanks!

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    Default Re: Repairing keel separation

    Are there bolts in there? Do you have the plans? Maybe shoot someone who’s building/built one a query? I’d be getting it swelled before tightening bolts too.
    Last edited by Andrew Donald; 08-13-2022 at 12:28 AM.

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    Default Re: Repairing keel separation

    You could fill it with a reasonable mastic (not a silicon) which will keep the rain/fresh water out while on the hard so that it shouldn’t rot but it will still be able to “come and go” - ie compress if/when she takes up in the water again. If you fill it with just epoxy it will compress the timber fibres around the epoxy when it takes up and so will likely open up again when she dries out again.

    Another option would be to clean and even out the crack (with a circular saw or router) and glue in splines from each side allowing them to fit around the bolts.
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  13. #13
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    Default Re: Repairing keel separation

    so, if yer building an epoxy boat, don't attach it to a caveman keel ,maybe ?

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    Default Re: Repairing keel separation



    I do not remember there being anything specified in the plans regarding how the deadwood was to be built up. Appears to be another crack opening up under the lower gudgeon?

    How about routing out a 1/4" deep by 2" wide rabbet along the aft edge of the keel? Do both sides and epoxy in long strips to brace the whole thing. The pictures I took of this boat under construction are long gone but in my head it is made of purpleheart.
    Steve

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    Default Re: Repairing keel separation

    At least going off of Stromborg's construction photos, Im not entirely sure there is a bolt there. I'll go digging around underneath it where I can get today

    http://forum.woodenboat.com/showthre...aff-Yawl/page3

    At least with the way this is constructed I don't think if the Keel rots in a few years it will affect the hull. I can potentially cut it out and reglue a new piece if it ever goes downhill. I may be overthinking it.
    Last edited by skerry; 08-13-2022 at 09:56 AM.

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    Default Re: Repairing keel separation

    Quote Originally Posted by stromborg View Post

    I do not remember there being anything specified in the plans regarding how the deadwood was to be built up. Appears to be another crack opening up under the lower gudgeon?

    How about routing out a 1/4" deep by 2" wide rabbet along the aft edge of the keel? Do both sides and epoxy in long strips to brace the whole thing. The pictures I took of this boat under construction are long gone but in my head it is made of purpleheart.
    haha funny you replied just as I was posting pics to your construction photos. Unfortunate I don't have any detailed photos of Moonbeam. The reply I got from David is

    "Yes, the keel is solid chunks of purple heart. They were glued together with epoxy and screwed together with very large bronze screws. Purple heart is a very heavy wood with exceptionally high degree of stability. It doesn't shrink or swell very much. It is extremely rot resistant. But all woods do shrink and swell somewhat with moisture and temperature differences. Even if all the seams were to open up, the large bronze screws would hold it together. I don't think you will ever have any trouble with the keel. I think I would fill any gaps with epoxy before you paint. The whole hull was coated with three coats of west system epoxy, with hand sanding between coats. "

  17. #17
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    Default Re: Repairing keel separation

    The way to stabilize the large chunks is to run MORE saw kerfs into the wood lengthways, not cutting bolts, and fill those new kerfs with epoxy, thus , creating a laminated deadwood/keel, not to retro fit splines into gaps gaps.
    or , ignore the failed epoxy joints .
    ...how does one screw large timbers to one another ?

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    Default Re: Repairing keel separation

    Quote Originally Posted by wizbang 13 View Post
    The way to stabilize the large chunks is to run MORE saw kerfs into the wood lengthways, not cutting bolts, and fill those new kerfs with epoxy, thus , creating a laminated deadwood/keel, not to retro fit splines into gaps gaps.
    or , ignore the failed epoxy joints .
    ...how does one screw large timbers to one another ?
    You're saying open the space more and fill with thickened epoxy?

  19. #19
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    Default Re: Repairing keel separation

    open MORE spaces .saw the big nogs into little nogs
    smaller pieces of wood are more stable than big ones.
    3, 2 inch plans are more stable than one ,six inch plank.
    That is why teak decks are always narrow, it is why strip plank boats do not leak, it is why your deadwood is moving as it dries out, and will move when it gets wet again, and will move when it dries out again, and on and on.

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    Default Re: Repairing keel separation

    Consider:
    1) this source, zero experience
    That said.
    2) flexible epoxy in a seam/kerf wide enough to let the epoxy stretch a bit
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    Default Re: Repairing keel separation


    The gaps in question are in the deadwood area below the waterline with the lower rudder hardware assembly hanging off one end. From experience, the boat does develop a bit of weather helm when wind pipes up, I worry about the deadwood "working" and the gaps just getting worse over time if the whole thing isn't stabilized.
    Steve

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    Default Re: Repairing keel separation

    Quote Originally Posted by stromborg View Post

    The gaps in question are in the deadwood area below the waterline with the lower rudder hardware assembly hanging off one end. From experience, the boat does develop a bit of weather helm when wind pipes up, I worry about the deadwood "working" and the gaps just getting worse over time if the whole thing isn't stabilized.
    I'd really feel more comfortable stabilizing it but based on all the feedback I'm still unsure the best route :P I suppose I could try a taking the rudder off, finding a way to push from the bottom to close the gap (no idea if this will work) and glassing the sides over the cracks. Wonder if I can contact Iain Oughtred for his opinion

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    Default Re: Repairing keel separation

    It looks like the keel was built to the plans. Several slabs vertically stacked for the aft deadwood and rudder post There might not be any fastenings in the area of the top crack, with total reliance on the glue joint. Not the best arrangement IMO, but I wear a belt plus suspenders.

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    Default Re: Repairing keel separation

    So I think my plan of attack is cleaning the cracks, filling with 5200, cutting out the aft edge and glueing a piece of okume plywood with epoxy/glass there to hold the pieces together and stop further separation. The only thing I'm wondering show strong that glue will be if Im gluing the side of the ply to end grain. I suppose I could always throw a screw or two into it.

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    Default Re: Repairing keel separation

    On the Caledonia Yawl 4-plank the rudder post/aft stem extends all the way down to the bottom on the deadwood, essentially acting like a cap on the deadwood end grain, preventing the deadwood seam from opening.

    Cutting away a few inches of the skeg/deadwood and replacing it with a new vertical trailing edge might be an option.

    I don't like the okoume fix, mostly because okoume is not at all rot resistant, and a thick-ish solid trailing edge in a rot-resistant wood would be a permanent fix.

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    Default Re: Repairing keel separation

    okoume is what I have :P I can look into acquiring some other wood.

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    Default Re: Repairing keel separation

    Quote Originally Posted by skerry View Post
    okoume is what I have :P I can look into acquiring some other wood.
    IMO okoume would not be a good choice, because it is plywood and not very rot resistant, and the end grain would be totally open. Sapele, purpleheart, white oak, red meranti, and many other solid woods would be a better choice. Okoume plywood, no.

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    Default Re: Repairing keel separation

    Amongst many of my new learnings owning a much larger boat now is that purple heart does not bond well with epoxy (it was mentioned the oils is the wood can affect it) though I suppose since the keel is already purpleheart I don't get much choice (and perhaps its the reason I'm seeing the separation that exists now..)

    Anyway appreciate all the learning and suggestion I've gotten so far. You all are great. I'll find a better block of wood and cut in a bit further.

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    Default Re: Repairing keel separation

    Quote Originally Posted by skerry View Post
    So I think my plan of attack is cleaning the cracks, filling with 5200, cutting out the aft edge and glueing a piece of okume plywood with epoxy/glass there to hold the pieces together and stop further separation. The only thing I'm wondering show strong that glue will be if Im gluing the side of the ply to end grain. I suppose I could always throw a screw or two into it.
    I would go old school mechanical, rather than relying on glue on possibly contaminated wood.
    Let in a pair of bronze fish plates, fastened with three copper clench bolts each side of the join. A copper or bronze drift driven up into the joint would also stabilize it.
    It really is quite difficult to build an ugly wooden boat.

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    Default Re: Repairing keel separation

    Surface energy is important when bonding. You want high surface energy and proper prep can increase it. Find how to prep the purpleheart and do test some samples.
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    Default Re: Repairing keel separation

    Quote Originally Posted by Peerie Maa View Post
    I would go old school mechanical, rather than relying on glue on possibly contaminated wood.
    Let in a pair of bronze fish plates, fastened with three copper clench bolts each side of the join. A copper or bronze drift driven up into the joint would also stabilize it.
    I've been mulling over using lag bolts to fasten it with the glue, I'll be honest I have no idea what a fish plate or drift is but I'll do some googling.

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    Default Re: Repairing keel separation

    I agree with Peerie Maa on this one, I'd likely do fish plates or strapping to solve the problem. Easy to remove later if necessary and not much work to install. Below is a definition of the terms used, as with many such definitions it shows the regional modifications of terms but is sufficiently accurate to explain the notion behind our suggestions. I likely would use through bolts because they're easy to get around here, but I suspect that is much more of a regional difference than a substantive one.

    "Drift Bolt: A long fastening driven (pin) or threaded (bolt) to receive end nuts and used for joining heavy timbers such as horn timbers and stern frames, also used to fasten and reinforce wooden panels on edge, such as centreboard trunks. The hole into which a drift pin or bolt or treenail is driven is called the drift."

    "Fish Plates: Wood or metal plates used for securing together the ends of a lengthening joint in any form of structural work."
    https://www.iims.org.uk/wp-content/u...ding-terms.pdf

    Nicholas

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    Default Re: Repairing keel separation

    We’re talking about a bolt going through a plate, vertically to hold the blocks from separating more, right ? I assume the downside is more drag but probably a lot less than my motor

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    Default Re: Repairing keel separation

    Quote Originally Posted by skerry View Post
    We’re talking about a bolt going through a plate, vertically to hold the blocks from separating more, right ? I assume the downside is more drag but probably a lot less than my motor
    No, fish plates are let into rebates on the side of the timber, spanning the joint. They can be straight straps, or butterfly with effectively a dovetail on each side of the joint. One on each side, secured with peened/riveted through fastenings.
    Drifts are basically big nails, made from round bar, pointed and driven into a tight blind hole.
    Rough sketch of fish plate and drift
    cracks.jpg
    It really is quite difficult to build an ugly wooden boat.

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    Default Re: Repairing keel separation

    Those are not cracks, they are movement gaps between separate bits of timber. Totally normal as things dry. Gluing them originally probably worked for a while, but was a bad place for epoxy. There should be drift pins or bolts holding the whole sandwich together. If not add some. Apply your goop of choice into the gap, I would use seam compound but don't use anything hard like epoxy. Paint and worry no more.

    It could have been prevented by laminating the deadwood from small bits, but it isn't a big deal unless leaks are resulting, then a stopwater will be needed.

    Bummer that the lower gudgeon bolt is right in a joint, but I wouldn't sweat it too much unless that joint gets progressively worse. The timber is long and well anchored to the boat so strength should be adequate.
    Last edited by J.Madison; 08-18-2022 at 06:25 AM.

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