Rootman's Coho Build

Discussion in 'Boat and Accessory Building' started by Rootman, Mar 1, 2006.

  1. Rootman

    Rootman Paddler

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    Here are some things I learned along the way to building a Coho:

    1. This boat has a lot more butt joints than the smaller Pygmies. They give you just enough clear mylar that you have to reuse pieces of it on several joints, which I didn't like (but it may be OK with everybody else), because it got rough from dried epoxy and bent from peeling it off. I looked in craft stores for clear mylar to no avail, but found clear plastic presentation covers (from GBC) in an office supply store, cut them to size, and the material worked better than the mylar (didn't stick as much).

    2. When you attach the extensions to the three center temporary frames, make it a strong connection. The wobbling of my loosely attached extensions made my frames keep coming loose from the inside hull. The hot glue won't hold under lateral stress.

    3. The problem above made me have to build outside "reverse" frames to hold the hull shape right. To do this, don't trace the frames, just mark the position of the corners and connect the dots with a straight edge to get the proper polygon. Add 5 mm to compensate for thickness of glassed hull. If you use one-inch plywood instead of quarter, the outside frames make a great support to keep the kayak in for completing the kit and for subsequent outside storage. In order to get the three frames to line up straight and hold the boat level, you need to know how much plywood extends beyond the sheer above/below each frame. I will post these empirical measurements later, if anyone is interested.

    4. It's nice that they give you a few rubber gloves, but I ended up needing about 4 dozen.

    5. I have visible drips from thickened epoxy dripping from the hull panel seams. It's not enough to wipe off the excess, as the epoxy with wood flour darkens the raw panels, pretty deeply below the surface. So wipe in a broad, undrippy shape, or sand the wood all the way down to the original color. Once you put a saturation coat over the drips, you're lost. On the deck, I might add some wood flour to my saturation coat if I can't sand away the drips. The hull I should paint, I guess.

    6. When you have leftover clear epoxy between early steps, coat your coamings with it.

    7. I saw online where someone saved money on C-clamps for coamings by cutting 4-in Schedule 40 PVC pipe into 1.5-in sections, with a slit to make a springy clamp. This will save about $40 or more in clamps, if you were going to get 20.
     
  2. DarrenM

    DarrenM Paddler

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    I had the same problem, I cut some triangle pieces of osb and glued them to the temp frames and my work surface. It worked great.
     
  3. Dan_Millsip

    Dan_Millsip Paddler & Admin

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    Good points Rootman -- I'd like to address a few if I might,

    Nice to know that you found an alternative with the plastic presentation covers. I can't remember specifically when I built my double but I think I had enough mylar in my kit that I didn't have to reuse any. I'll let you know about my Coho when I get to that point.

    I've noticed that this part of the constuction of Darren and Mark's boats is a bit different from the process used on my Osprey Double -- thanks to you and Darren for the heads up on how to avoid a problem here.

    I think that Pygmy gives you examples of gloves, syringes, etc., to show you what you need to get. My take is that they try to keep the overall cost of the kit as affordable as possible. I'm sure that they could add a box of gloves but would have to increase the cost of the kit by $20 or more to do so. I picked up 100 gloves at a local supplier for $11. I figure it runs about $200 (CDN) above the kit price to complete the build (gloves, syringes, sandpaper, rollers, respirator, etc). All told, it's still a bargain compared to the cash outlay to purchase a commercially manufactured kayak.

    I don't see where this is any fault of Pygmy. No offence intended, but it seems that it's more of a case of not working neat enough.

    Good tip. There's also hatch lips and bulkheads (if you're using a hatch kit). I also found it was cool to use any extra epoxy for making small sculptures on the end of my workbench. :wink:

    Yup. There's a bucket full of them in the shop where I'm building my Coho. There's also a great deal of tips and tricks to learn about kayak building at Nick Shade's Kayak Building Bulletin Board. I highly recommend anyone building a wooden kayak to visit Nick's site:

    http://www.kayakforum.com/cgi-bin/Building/index.cgi

    Getting back to Pygmy's kits, I think that the kits are absolutely brilliant! I recall while building my double that there were several occasions where I was thinking "what an awesome process, a great deal of thought went into this". They're easy to build and in the end you've got something that you can be proud of and get some real good use from. And let's face it, the kits need to be designed in such a way that someone without any experience working with wood and epoxy can be successful.

    Basically, the manual and the process are designed for the lowest common denominator -- but you'll also notice that there are a number of people (yourself included) who have deviated from the instructions a bit. I did it on a number of instances with my double. A good example was when I cut my hatches -- Pygmy suggests cutting the hatch openings by hand using a fine tooth sabre saw blade held in a pair of Vice-Grips. I got about half an inch into the cut before attaching the sabre saw blade to a sabre saw. I've got a good deal of experience with woodworking tools and didn't have a problem making a nice cut -- but a novice with a sabre saw could end up with a catastrophic mess.

    On my Coho I'll be deviating even more from the Pygmy instructions -- things like bulkheads and foot pegs will be installed before installing the deck. These sorts of short cuts aren't for everyone, but some will find them useful. If someone who has never attempted to build anything like this before follows the intructions to the letter, they're going to end up with a good, functional (and awesome looking) boat when they're finished.

    *****
     
  4. Batstar

    Batstar Paddler

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    As Dan mentioned earlier, the instructions for the manuals must vary from model to model. For the Tern 17, Pygmy suggests to wire all of the temporary frames to the panels , including the bow and stern end frames, until they are tight up against the frames. I guess it’s one method that would allow you to use less hot glue along the frame edges. That said, I still spent a fair amount of time scraping off the any remnants of hot melt from the inner hull. FWIW, I found that the clear glue sticks were easier to remove than the white stuff.
     
  5. Rootman

    Rootman Paddler

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    I have nothing but praise for Pygmy. I mentioned the gloves because I would buy a dozen at a time, and had to keep going back. A new builder might think the couple of gloves in the kit were enough. I also ordered additional syringes from Pygmy, but didn't need them. They cleaned up OK.

    My drips are just my fault. My beagle kept jumping on me when I was gluing the seams, so I was just mentioning it as a remedial issue if a noob did get the drips. I have seen it mentioned on other sites, where people have then chosen to paint their boats, which is fine with me.

    The Coho manual specifically mentions reusing the mylar, so it's part of the plan. I like that they are conserving - it just didn't work for me and I thought it was interesting that the other plastic (maybe acetate) seemed to work better with the epoxy.

    Really, in light of the kind of finishing work you guys are doing, I am hardly worthy to make any suggestions.
     
  6. Rootman

    Rootman Paddler

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    Same with the Coho, but the wires come out when you glass the hull, and that's where the wobbles became a factor.
     
  7. Peel

    Peel Paddler

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    Actually the Coho manual calls for the same thing:

    It adds a few more holes, that will be visible when the boat it done, but will certainly keep everything tight until the epoxy sets up.
     
  8. Dan_Millsip

    Dan_Millsip Paddler & Admin

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    I agree, it would be a good idea if Pygmy added a list of other supplies that are needed -- at least the stuff you absolutely need.

    Oh, it's the beagle's fault. :wink: This reminds me of a fellow who was building a strip kayak and his cat came in and jumped up on it, just as he finished applying the last coat of epoxy. Ugh.

    Hmmm... I must have missed that part (I've only read the manual twice since I received it).

    Hey, make all the suggestions you want. Your boat looks pretty good from the pictures that I've seen --besides, it's talking about and sharing ideas that make us all better at what we're doing.

    *****
     
  9. Rootman

    Rootman Paddler

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    At the point when the wires come out of the temporary frames, you have epoxied the panel seams (partially), and you are about to go over the seams again with thickened epoxy. But you haven't glassed the hull yet, so it isn't really rigid and set up, except for the pulling-in force of the now glued-only temporary frames. If the glue doesn't do its job (due to climate, wobbling, and/or jumping dogs), the hull can go a little wide on you. (Then you can have a tandem side-by-side double-cockpit Coho). My hull separated from the inside frames AFTER I glassed it, and reglueing wasn't strong enough to hold it in place. Even then, the hull was flexible enough to be pushed into shape with the special reverse outside frames.

    The key is to attach the extensions very well and avoid the wobbles, I think.
     
  10. Rootman

    Rootman Paddler

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    [​IMG]

    Traditional ships had a figure on the bow, called the maidenhead. Bad luck befell any sailor who inadvertently broke the maidenhead, for he was surely doomed to leave his shipmate's behind.
     
  11. Rootman

    Rootman Paddler

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    The gator head bolts into the bow pour and its lower jaw accommodates a toggle line. The whole head is sprayed with Krylon microbead clear reflective paint. Illegal within national park boundaries.
     
  12. Dan_Millsip

    Dan_Millsip Paddler & Admin

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    Do you have a better picture?

    *****
     
  13. Rootman

    Rootman Paddler

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    Yeah, the dog jumped on me while I was taking the shot.
     
  14. Dan_Millsip

    Dan_Millsip Paddler & Admin

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    LOL. :lol:

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  15. Steve_Fairbairn

    Steve_Fairbairn Paddler

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    Is that an alligator head?
     
  16. Dan_Millsip

    Dan_Millsip Paddler & Admin

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    Sounds cool.

    Which part is illegal? Spraying with Krylon microbead, or having the gator head?

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  17. Rootman

    Rootman Paddler

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    Just kidding about illegal. Alligators used to be endangered here, but now they are plentiful, a suburban pest, and farmed for food (McGator Nuggets, anyone?). The dried head is hard as a rock, and the mount I am making will be unscrewable, so I can swap out different bow figures (considering a beagle skull, soon to be available...) depending on season and mood. Looks kind of Vikingesque. The clear spray reflectant is neat -- it's also used illegally to spray on car license plates to foil flash-photo enforcement systems at toll booths. Everyone should shoot this stuff onto their paddle tips, for safety.
     
  18. DarrenM

    DarrenM Paddler

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  19. Rootman

    Rootman Paddler

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    Dan wrote on his thread:
    I have been admiring the workshops, garages, and attics of the kayak builders here, but for the benefit of the prospective builder, it needs to be said that it is possible to build a Pygmy in the back yard --- so don't let the lack of a fully equipped woodworking shop stop you.

    However, so far I have had to epoxy while dealing with sun, darkness, rain, playful pets, frisbees, suicidal epoxiphagic insects, bird droppings, and worst of all, snails.

    I can hear it now: "Cool, how did you get those little seashells to stick to the boat?"
     
  20. Astoriadave

    Astoriadave Paddler

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    "Epoxiphagic" has gotta be a word I never expected to see anywhere! Varnishophagic, yes.