Wood Duck launched

Discussion in 'Boat and Accessory Building' started by steele, Jun 9, 2008.

  1. steele

    steele Paddler

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    As a winter project I built this short recreational kayak from a CLC kit. The idea was to have a stable easy to paddle boat for friends to use and to take with us on a larger boat. It is very light and should be easy to get on deck. It also has a larger hole near the water line through a big end pour so it can be towed. It was not a very easy build compared to the previous Pygmy Osprey and CLC C-17. I think a hard chine 10 foot long 30 inch wide yak stresses the limits of stitch and glue construction and getting the hull closed at the bow and stern was a real trial. In either case it floats!

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  2. fishbust

    fishbust Paddler

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    duck

    Looks good from here. Nice job! 8)
     
  3. Astoriadave

    Astoriadave Paddler

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    That looks really nice, steele! A lot of boat in a very short length.

    Scanned the construction photos on the CLC site. I see what you mean about joining the plywood at the ends! Did you wet the plywood at the ends, as they show? If so, did it help much? Mick Allen has used a heat gun to ease plywood bending, so maybe you did also?

    I am curious about your end pour for the tow attachment hole. Where did you place it? Just at the lower end of the stem, at the chine? If you have a photo, would appreciate seeing where you put it. I have been puzzling over placement of tow attachment for a small nesting pram for a similar application, wondering how to get the right spot, even thinking it might have to be back a bit.

    Thanks.
     
  4. steele

    steele Paddler

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    I did wet the ends with very hot water which seemed to help, mostly by reducing the risk of the wood splintering. I also drilled lots of extra stitch holes near the ends and used thicker wire in high stress areas. I broke LOTS of stitches before that point. Perhaps steaming the wood would have helped also, but I did not have the equipement or the skill for that.

    I can not give you much advice about the towing location. I put the bridle hole just above the chine (A little more than half way down the stem). I have not yet had a chance to tow it. I could not figure out a way to test multiple locations without drilling multiple holes, so I looked at dingys around the local marina and estimated the location. The end pour is the heigth of the bow which is very verticle and big enough I could drill a second hole if need be. I will let you know how it works once the weather around here clears up enough to get out on the water and give it a try.

    I had asked for end pour advice awhile back and come up with this after minimal experimentation. I mixed the epoxy well then added 2 parts microballoons to 1 part cab-o-sil until it was very thick but still pourable. The resulting test blob was reasonably light and could not be damaged by putting it on a cement floor and beating on it with a hammer. I think the ratio could be increased to 3:1 with similar results.

    Tom
     
  5. mick_allen

    mick_allen Paddler & Moderator

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    that is a nice little boat. (i have to play around with that idea.)
    i also found that lots of stitches give lots of control and lots of force spread over an area without putting in localized stress that fewer stitches would give.
    i used a small heat gun (with banding) for localized bending - but it would be harder for a whole panel's curvature like in the duck

    as far as pulling is concerned, that duckyak is so stable that the mid location chosen should be no problem. With narrow ordinary yaks that can turn over real easy, i would (have on one) put the power tow point below the cg - say the waterline or below. That way the tow pull serves to right the boat if it leans rather than add to the overturning moment that a tow at the bow peak can add.

    it looks great on the water.

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  6. Astoriadave

    Astoriadave Paddler

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    Thanks for the added info, steele. You, too, Mick. I'll remember that bit about keeping the tow point below the CG. And, I will be paying attention when steele reports back on towing success.

    BTW, that use of microballoons to dilute the end pour sounds good to me. Plenty of native strength in the resin in a bulk application like that.
     
  7. mick_allen

    mick_allen Paddler & Moderator

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    its probably got more to do with lateral stability (or secondary depending where you call it) as the lateral CG actually changes by where (and how much!) the yak is pulled from (it's adding a new, ever changing, force to the system from the tow location).
    for example, even if the tow was below the cg of a sharp railed surfyak, a side pull would still trip it over. but as the lateral stability would not be positive, it gives a better indication.

    Distilling all that, and all things being equal, i would think lower the better.

    but back to the duck, steele! how did you build the deck?

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  8. steele

    steele Paddler

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    The deck is a pretty elegant design. The stern panel wraps all the way forward to encircle the cockpit and is pretty flat. The bow panel is bent over forms for a cambered shape. The side panels do not reach the bow or stern and are pretty steep at the cockpit for clearence. The deck is stitched and glued over forms which are then removed. The deck is attached to hull without sheer clamps.

    The challenge is that the deck wants to spring flat and the hull tends to return to a narrow shape. Because of CLC's building technique the internal forms have to be removed before the hull and deck are fully "set" in epoxy, so the deck overlaps the hull. Most (including me) building the 10 foot version who are on the CLC forums could not get the 2 to meet and ended up simply getting it close and planing of the overlapping deck. Not very exacting compared to my Pygmy build in which the 2 were almost perfectly aligned, but it worked in the end.
     
  9. steele

    steele Paddler

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    I sure messed up the whole quote thing. :(

    (edit performed - admin)
     
  10. mick_allen

    mick_allen Paddler & Moderator

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    all woodwork (and other stuff, too) is just a succession of fixing errors anyway - and from what i see, no one would know.
    (as an aside, on the playak 'facetious', i hot glued the deck with scrap pieces to a scrap armature in order to keep it's shape when separated from the hull)


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  11. steele

    steele Paddler

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    I agree. I tend to learn more when things go other than planned anyway, and the challenges did not have much impact on the final result. I did get a e-mail today from CLC for a new wood duck deck option that I think would help anyways. They call it a hybrid,

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