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Thread: Need to repair frames on Cartopper

  1. #1
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    Default Need to repair frames on Cartopper

    Hello Everyone,

    I recently bought a used Cartopper (11.5' plywood Bolger design) and some of the plywood frames are delaminating (she was left right side up on the beach for several months and filled up with ice). The attachment to the hull mostly looks sound, so I'm considering the following approach. Dry it out, clean up the cracks as best I can (possibly wash them out with alcohol?), saturate with epoxy, fill with thickened epoxy, run glass tape over the edges of the frames, overlapping the existing glass holding the frames to the hull. Does that sound at all reasonable? I have some experience with epoxy and fiberglass, but not much with boat repair. A few people have suggested that I sister new frames to the damaged ones.

    Thanks for the help!

    IMG_0113.jpgIMG_0092.jpgIMG_0109.jpgIMG_0115.jpgIMG_0116.jpg

  2. #2
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    Default Re: Need to repair frames on Cartopper

    What you propoae is iffy and as it looks like there are several places where structure is compromised, the probability of fixing all of them is not great.
    I'd replace all he affected frames.

  3. #3
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    Default Re: Need to repair frames on Cartopper

    You can't easily clean out gaps like that. It will be easier and better to just cut away and grind the damaged frames down to the plywood planking and replace them. The frames were important in the building process. The original frames were part of the building jig, so they located the planking. Now the planking is locating the new frames, so solid wood will be better and easier to use than plywood to replace damaged frames. The hull will hold its shape without them fairly well, so you can safely remove one bad frame or section of a bad frame at a time and replace it. Just cut between the oarlock support and the frame and leave the oarlock support in place if it is in good shape.

    Cut out one frame at a time and replace them with 1x2 or 1x3 cedar or similar wood frames. Saw the bad frame close to the hull and grind the rest down to the plywood hull or fiberglass coating if any. make a replacement frame that fits reasonably well. Thickened epoxy is the alternative to a perfect fit. Add a strip of 2 inch (50mm) glass tape where the frame will be installed, then a 3" tape. Then bed the wood frames in thickened epoxy at the center of the tape strips before the epoxy is fully cured. Form a bit of a fillet. to hold the frame in place, use several brass screws through the plywood sides. Once it sets up, you can cover the screw heads with thickened epoxy or remove them and fill the holes. This is an instant boat, not a work of art.

    My Gypsy was picked up by a gust of wind last winter and hit a tree, shattering the gunnels, some of the plywood planking and the frame at the right in the picture below. I cut out the broken part of the frame above the seat support and replaced it with cedar as described above. The angle grinder is a handy tool for fine wood butchery.

    IMG_1636.jpg
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  4. #4
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    Default Re: Need to repair frames on Cartopper

    Those plywood “frames”/ bulkheads look only partially delaminated to me . The filets to the ply hull seem unbroken , so I do not see a lot of loss of strength. I’d just dry it , wedge the lams open , pour in some Epoxy and clamp em back together.
    Maybe beef up the funky looking corner at the chine.
    Be aware , there is no such thing as “saturating “ with epoxy .
    Glassing the end grain of half inch ply is pointless.
    Most of the work involved will be sanding up the epoxy mess , so try to work neat .
    Dont put epoxy over paint

  5. #5
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    Default Re: Need to repair frames on Cartopper

    Thanks! What Whizbang said is pretty much what I had in mind. "Saturate" was a poor choice of words, I just thought maybe straight epoxy would find its way into smaller crevices, and thickened might be needed to fill the bigger gaps. However, MN Dave makes replacement sound doable. Working with solid wood is a lot more appealing than trying to reproduce the plywood frames. The worst of the damage is on the aft frame, so maybe I'll replace it and "repair" the other one. I would not have thought of putting glass tape between the hull and the new frame. Is that to strengthen the hull, the joint, or both?
    Thanks again.

  6. #6
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    Default

    Quote Originally Posted by d.moriority View Post
    Thanks! What Whizbang said is pretty much what I had in mind. "Saturate" was a poor choice of words, I just thought maybe straight epoxy would find its way into smaller crevices, and thickened might be needed to fill the bigger gaps. However, MN Dave makes replacement sound doable. Working with solid wood is a lot more appealing than trying to reproduce the plywood frames. The worst of the damage is on the aft frame, so maybe I'll replace it and "repair" the other one. I would not have thought of putting glass tape between the hull and the new frame. Is that to strengthen the hull, the joint, or both?
    Thanks again.
    The removal of paint is the real problem. Make new frames pattern With 3" +- wide 1/4" ply on edge & hot glue. kind of how they make plywood patterns for countertops but in this case you're doing it vertically

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  7. #7
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    Default Re: Need to repair frames on Cartopper

    To remove the filleted and glassed in ply frames is a big job. One can sawzall them away close to the hull, then grind the glass and filet away. If you wail on them with a maul, you risk de lamming the skins of the hull! The grinding will be messy and itchy. You will need a proper disc sander. For these reasons I would try very hard to save/ restore the existing bits. If you feel the hull is flexing too much , ADDING a set of plywood gussets between the bottom and sides would be comparatively easy.

  8. #8
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    Default Re: Need to repair frames on Cartopper

    A lot depends on what you want to end up with -- a repaired copy of the original and as light as possible for cartopping, or something to leave on the beach, or something to fix quick 'n dirty and tow on a trailer? Will you sail her hard or just paddle the duckpond? Use with an outboard??

    For quick 'n dirty with minimum cost and work, your idea of drying, filling with thickened epoxy and taping should work -- but might fail under sail or power. For semi quick 'n dirty you could sister the frames and tape them together with epoxy -- but that makes the boat stronger and heavier. Otherwise Wizbang's recommendation for sawing them out and replacing is the best -- he's got lots of experience with ply construction!
    Last edited by Thorne; 02-19-2018 at 10:28 AM.
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  9. #9
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    Default Re: Need to repair frames on Cartopper

    I believe fixing the ply frames will end up being relatively short term fix and a few years down the road you will need to replace them because of rot. Now that they have opened up all the microbes of decay have entered the wood and broken glass.

    Everything said before is correct, so chose your posion.

  10. #10
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    Default Re: Need to repair frames on Cartopper

    Quote Originally Posted by wizbang 13 View Post
    Those plywood “frames”/ bulkheads look only partially delaminated to me . The filets to the ply hull seem unbroken , so I do not see a lot of loss of strength. I’d just dry it , wedge the lams open , pour in some Epoxy and clamp em back together.
    Maybe beef up the funky looking corner at the chine.
    Be aware , there is no such thing as “saturating “ with epoxy .
    Glassing the end grain of half inch ply is pointless.
    Most of the work involved will be sanding up the epoxy mess , so try to work neat .
    Dont put epoxy over paint
    I agree with Bruce. This is an easy one weekend project that should last,...... oh,.. about 5-10 years if not abused so much again.

  11. #11
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    Default Re: Need to repair frames on Cartopper

    +1 on wizbang_13 and nedL comments . . . . . repair without rebuild and use it.
    => as to checking the integrity . . . do what a surveyor would do (a) gently tap with a small piece of soft pine/etc and 'LISTEN', you can hear rotten and delaminating, (2) gently pound with a softish rubber hammer and listen and 'FEEL' if it is buzzy , vibrating, loose or solid and tight, a couple of little bad spots will not kill a structure and if you plan to sail smooth waters in good weather near shore with safety gear and are a good swimmer then you can . . . . . . .
    This is the first lesson ye should learn: There is so much good in the worst of us, and so much bad in the best of us, it doesn't behoove any of us to speak evil of the rest of us.
    E. Cayce

  12. #12
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    Default Re: Need to repair frames on Cartopper

    Okay then! It's starting to come into focus. It'll be on a trailer or in the back of a pickup so weight's not a major consideration. I plan to row the boat more than sail it (which I suspect puts less strain on the hull, even in a chop?). It sounds like I can do the quick and dirty patch and see how much I like the boat before committing to a real repair. But really don't bother wrapping glass around the edge of the frames? I know it's tricky to do but the corners aren't very sharp and it seems as though it would protect them from further damage. Or not, there's obviously a lot of experience here!
    Thanks!

  13. #13
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    Default Re: Need to repair frames on Cartopper

    It is hard to get glass to wrap around a small radius. It will want to lift up and form bubbles.

    My earlier suggestion to put tape under the frame was to spread the load to avoid a hard spot, and probably somewhere between overkill and ineffective. The planking is thick enough that you don't need to use tape under the bulkhead. I was thinking of thinner planking. 3mm plywood will be more sensitive to a hard spot at a frame.

    Bruce (wisbang 13) may be right. It depends on how waterlogged the frames are and how long they have had to dry out. Obviously, I like my suggestion better. I agree with the sawzall and disc sander, but good disc sanders aren't a common as angle grinders these days. Both work. While I prefer the 7" disc sander, I have an angle grinder. My frame was crushed, so I replaced it. I would not replace the plywood frame with another thin, uncomfortable ugly plywood one. The thin, deep frames are not as nice as sawn frames, but they are part of what makes an instant boat instant. It's like coffee, you can take a little more time and brew a good pot, but is a lot faster to nuke a cup of water and stir in the foul brown powder.

    I suspect that the surfaces where the fiberglass has delaminated will not clean up well enough to bond well. If you go the minimalist route and it opens up again, it is no disaster. You may have to redo the repair, and since will have more experience the second time around, it will be easier. The boat won't fall apart anytime soon if you ignore the damage and use as is. It will be ugly, and won't last as long as it will if you fix it.

    Dave
    Last edited by MN Dave; 02-20-2018 at 12:45 PM.
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  14. #14
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    Default Re: Need to repair frames on Cartopper

    Thanks Dave. That makes sense about the tape under the new frames, especially since the process of removing the old ones with the angle grinder could thin the plywood. I will at least need to grind away some paint, even to make instant coffee, and that may help me evaluate the damage. On the topic of tools, what about an occillating tool to cut out the old frames? It might be way too slow, but at least in my hands, they are a lot more controllable than the sawzall.

  15. #15
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    Default Re: Need to repair frames on Cartopper

    Quote Originally Posted by d.moriority View Post
    Thanks Dave. That makes sense about the tape under the new frames, especially since the process of removing the old ones with the angle grinder could thin the plywood. I will at least need to grind away some paint, even to make instant coffee, and that may help me evaluate the damage. On the topic of tools, what about an occillating tool to cut out the old frames? It might be way too slow, but at least in my hands, they are a lot more controllable than the sawzall.
    The noisy little buzzer (I will use one when the sawzall is too crude, but I don't like it) would be a lot less likely to chew up the wood on the other side. The slower cutting speed may be compensated by the closer cut (less grinding) and lack of collateral damage.
    Management is the art of counting beans. Leadership is the art of making every being count. --Joe Finch

  16. #16
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    Quote Originally Posted by MN Dave View Post
    The noisy little buzzer (I will use one when the sawzall is too crude, but I don't like it) would be a lot less likely to chew up the wood on the other side. The slower cutting speed may be compensated by the closer cut (less grinding) and lack of collateral damage.
    Oscillating tools really would work well for taking the frames out they were actually designed for undercutting door trim, baseboard, toe kicks, where a Sawzall just won't work. Kind of also works between Planks on a clinker boat for cutting the rivets I tried it but I need new blades so I wouldn't with a hacksaw blade pulled by hand.
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  17. #17
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    Default Re: Need to repair frames on Cartopper

    So the important thing to understand about the frames in a Payson, is that they vary between somewhat, to completely unnecessary in the first place. The big if is whether the boat was built using epoxy, or the intended inappropriate fiberglass resin (which works fine as Payson intended). The thing is many people realize the poly resin is not good, so they use epoxy instead. But they still put in all the unecessary frames. The extra frames add bonding area.

    (Amusing anecdote, I was at the Wooden Boat School one summer and this guy went so overboard with his two Nymphs he bonded in the frames, the plank seat, and he also bonded in un-called for transverse seating, there was barely anywhere to put your feet. He did do a nice job though. He used epoxy)

    So if you can figure out whether it is epoxy (what does it smell like when you grind it), and assuming you can verify it is epoxy, in many cases you don't really need all that much in the way of frames. There are similar S&G or CM boats with no ribs. Just take the frames down to the level of the filets, and cap with glass. I haven't built Cartopper, so you need to use some judgement, but in general those boats were significantly overframed. I built a number of his skiffs with no frames at all, and transverse seats, because that was what the client wanted. I know one of those boats is still good though launched in the mid 80s.

  18. #18
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    Default Re: Need to repair frames on Cartopper

    The Last Bolger/Payson I made, I glased almost the whole thing inside and out including the gunnels. I glassed the skeg, buit didn't wrap the tail end, and it split. When it dies, I will replace with corecell. I don't use the lumber in the chine, I make it all composite. It is a little more work at first, but it has been through over 20 winters and it is as good as new.

  19. #19
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    Default Re: Need to repair frames on Cartopper

    Tomcat, that's interesting about the choice of resin and the need, or lack of, for the frames. I know a little bit about the history of the boat, although nothing about the original build. There's a group at the local historical museum that repairs/ restores donated boats and sells them to raise money for the museum. Someone apparently gave them this boat after it washed up on their beach and was never claimed. The museum group sold it to the woman I bought it from. I know that they put a new transom in (solid wood, rather than the framed plywood transom on the plans) and added quarter knees and a breasthook. I'm sure they would have used epoxy on the work they did, but I don't know if they got into the frames at all. I can see if they remember! BTW, someone, probably the museum guys, installed a removable transverse seat, rather than the box rowing seat called for in the plans. What do you think of the box seat? I like the idea of not cluttering up the cockpit, but does anything other than gravity keep the box in place, while rowing? Unfortunately the previous owner misplaced the floor platform so I'll need to make one. She also lost the mast!

  20. #20
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    Default Re: Need to repair frames on Cartopper

    These Bolger ply boats work as well as they do in part because of the serious amount of rocker he includes in his 3 and 5 panel models. But this also makes them very sensitive to longitudinal balance. The longitudinal bench seats and the box you mention, both allow rapid adjustment of trim, which is very helpful. The box allows the use of the floor for sailing, or camping. I'm sure you could find some practical way of securing the box with cleats or bungies, or straps.

    The main issue is to determine what you want to use the boat for, then you can figure out the best arrangement. I think it would be fun to have a sliding seat arrangement if one wanted to do a lot of rowing. With the length of the oars, no outriggers, and a beamy hull, you would not want much range of motion, but even a foot would be a game changer. The extension phase of the legs is the most explosive, so why not use it.

    A longitudinal bench is great, and can be made to lift out. But it does make the boat very tippy to move around in as ones weight is either too high or off center.

  21. #21
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    Default Re: Need to repair frames on Cartopper

    Thanks Tomcat, that all makes sense. The box is probably the place to start - simple and flexible - but a sliding seat would be fun! I think I saw plans for one in Small Boat Monthly. I have the damaged frames pretty well dried out and hope to fill them with epoxy as soon as we get a warm day.

  22. #22
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    Default Re: Need to repair frames on Cartopper

    I had plans at one point for a simple rowing skiff, not as sophisticated as the skulls we used to row, but basically just sheaves on four corners of a very simple seat/thin box, rolling on some aluminum rods. Not really a big deal. One has to be realistic, it is bad for the body to develop energy that the boat is too fat to use (not that this boat isn't going to row nicely). But with reasonable oars it is just an exercise for getting the legs a little into it. Even foot braces increase efficiency a lot.

    Have fun with the boat.

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