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Thread: Tip 'n roll kayak

  1. #1
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    Default Tip 'n roll kayak

    I thought I wasn't going to start a project this winter, but the water froze up and we couldn't travel thanks to covid, so I decided to scratch an itch and build a dedicated rolling kayak. I did have an eye on a kit sold by Pygmy kayaks, but they went out of business. And then, by some coincidence, I came across a link on the Qajaqusa.org site to free plans for a kayak that can be built as a dedicated rolling machine.

    The design is based on a West Greenland Disco Bay boat, but westernized in various ways to become a 3mm ply shell of a boat. The plan I'm following is for the Shrike R offered by CNC Kayaks.

    The instructions are quite detailed, and include a chart so you can scale the boat to your weight. In my case, that dictated building the boat to 92 percent of the size drawn. So I took the PDF of the panel shapes to my local Staples store. The next day, they had a 22-foot by 30 inch roll of paper for me.

    I ordered three sheets of 3 mm Okoume from Harbor Sales in Maryland. (Delivered to my house, no tranport fee.) Some slicing and scarfing and I'm ready to transfer the shapes to the wood.

    Here's the bottom panel laid out over a pair of 10" by 16' sheets of ply. With the scaling, my boat will be 19" in beam by 15' long. The aft deck will be almost awash. Minimal volume and width makes for an easy rolling machine. The plans also show a wider than usual cockpit to further facilitate various rolls.

    Bottom plan on scarfed ply.jpg

    I've never worked with 3 mm ply before. Very flimsy! But if I'm careful with my material use, the finished boat will be under 30 pounds.
    Last edited by Woxbox; 02-19-2021 at 09:29 PM.
    -Dave

  2. #2
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    Default Re: Tip 'n roll kayak

    I've entered new boatbuilding territory here. I've done a ply on stringer kayak, a couple of SOF lashed kayaks, and a stripper. But not a stitch and glue. The instructions suggest all of the usual techniques to pull these light 3mm panels together: wire, zip ties, tape, hot-melt glue, CA glue.

    I've started here with some zip ties and wire. Is there a consensus on just how tightly laced the hull has to be before you commit to epoxy and glass tape? It does seem odd drilling the panels full of holes - who wants to be paddling a perforated hull? Will an end rip off like a sheet of paper towel? I'm tempted to go to packing tape next.

    The internal molds in the photo are temporary. The finish bulkheads - just three of them - will be fitted after the inside seams are joined and the sheer clamps are in.

    Stiching around temp molds.jpg
    -Dave

  3. #3
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    Default Re: Tip 'n roll kayak

    I built a stitch and glue kayak out of thin panels back when and had these same questions. Zip ties and wires give you the ability to adjust fairness of the chines by way of adjusting the panel gap, before making it permanent with epoxy. Spacing and quantity of ties can be only as many as required to keep the shape until the epoxy and glass are hardened. Small variations or unfairness in the panel shapes can have an outsize impact on the shape, and you may even need to take it off your stands to really eyeball the curve of the chines.

    Looks like a good winter project!
    -Matt

  4. #4
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    Default Re: Tip 'n roll kayak

    It is best if the panels are touching, but epoxy+filler and glass cloth can bridge gaps.

  5. #5
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    Default Re: Tip 'n roll kayak

    Thanks for the tips. I've had plenty of experience gooping up gaps, so that will come easily. I did expect some fine tuning - the instructions predict it. But Here's a shot of the aft temp mold and how much I had to spread and push down the bottom panels to get a fair curve along the keel.

    This fairs it out with the external mold halfway between this mold and the center one. All three internal molds puckered up the bottom if the panels were taken up snug. But everything else fits as it should. So I'll adjust for fair lines, fill the gaps and move on.

    Panel fit.jpg
    -Dave

  6. #6
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    Default Re: Tip 'n roll kayak

    Yeah, I would try to trim down those edges so they meet together a little closer. You can run a jigsaw blade down the crack where the panels are too proud, or you can take it apart and plane it down a bit.

  7. #7
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    Default Re: Tip 'n roll kayak

    Thinking about what's going on here, it seems like the patterns were generated from the computer model without any allowance for panel thickness. The errors seem to be totally consistent with that. To cut out the panels, I stapled the patterns to the ply, cut close to the line and then sanded the shapes fair to the mark. So yeah, if I take away more from the tight areas (I've already removed some) it should come closer to the intended shape.
    -Dave

  8. #8
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    Default Re: Tip 'n roll kayak

    After a good bit of time fiddling with the fit of the seams, some filling, some shaving, I pulled it off the molds and eyeballed the chines and keel. Looked good enough. I then tacked the edged with a little CA glue and then ran a poxy goop between the stitching. I know there are other approaches, but I didn't wax the wire and don't want to work over the plastic ties, so I'll give it a couple of days, pull all the stitching material, and then complete the filets and run fiberglass tape over the inside seams.


    16 Filets between stiching.jpg
    -Dave

  9. #9
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    Default Re: Tip 'n roll kayak

    Sure is a slippery looking hull.

    What is it that you like about rolling? Me, I hate cold water.

    Also, what is that 4" pipe on the wall all about? I've never seen one of those.

  10. #10
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    Default Re: Tip 'n roll kayak

    Radon abatement?
    There's a lot of things they didn't tell me when I signed on with this outfit....

  11. #11
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    Default Re: Tip 'n roll kayak

    I read that as random abatement. You really had me there for a minute. And yes, that does look like an in-line fan.

  12. #12
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    Default Re: Tip 'n roll kayak

    Yes indeed, radon. The house sits on a pile of shale, under which there's granite bedrock which oozes radon day and night. But that inline fan has been running nonstop for more than 30 years, and keeps the readings below the sensitivity of the standard test. I still wonder how a pair of bearings can hold up that long. It doesn't even vibrate.

    The finished hull will be 14'11" by 19", depth at the back of the cockpit 6." One of the interesting questions making a boat like this is: How small a hole can you squeeze your legs into? I've decided that 9" clearance at the front of the cockpit is my limit. The feet will be forced into a toe-down position. The less volume in the hull, the easier it is to roll.

    And why roll? It's entertaining. Paddling up and down the local lakes gets old. Dressed for the water, one doesn't get cold.
    -Dave

  13. #13
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    Default Re: Tip 'n roll kayak

    The problem with stitch and glue and similar boat building techniques is the lack of good old-school tactile woodworking. This project calls for some hand-plane work just once in the build - shaving the sheer clamps down to the required line and bevel. That felt good.

    At this point, the hull is just over 10 pounds.

    Gunnels shaved down.jpg
    -Dave

  14. #14
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    Default Re: Tip 'n roll kayak

    Looking good, Dave.
    Rolling is fun

  15. #15
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    Default Re: Tip 'n roll kayak

    That looks lovely.

    Are you going low deck and small cockpit?
    I'd much rather lay in my bunk all freakin day lookin at Youtube videos .

  16. #16
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    Default Re: Tip 'n roll kayak

    So here's the cockpit with the bulkheads and deck framing dry fit and the seat dropped in for a sense of scale. The cockpit rim is a mockup to plan the laminated one yet to be built. So yes to low deck and small cockpit. The hull is 5" deep behind the cockpit, and I'll have 8 1/4" clearance under the masik. (I've fretted a lot over that dimension, it's tighter by about 2" than any other boat I've paddled.) The Cockpit is 19" front to back, but almost as wide as the boat for freedom of movement laterally. Yeah, it's going to be a tippy little thing, but easy over, easy back up.

    Cockpit mockup.jpg
    -Dave

  17. #17
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    Default Re: Tip 'n roll kayak

    That looks like an adequately roomy cockpit, but I'm coming from a slalom and squirt background - is there enough footroom to use conventional footrest(s) or will it need the hole-in-a-foam-pillar approach used by custom cut squirt boats?
    I'd much rather lay in my bunk all freakin day lookin at Youtube videos .

  18. #18
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    Default Re: Tip 'n roll kayak

    Quote Originally Posted by P.I. Stazzer-Newt View Post
    That looks like an adequately roomy cockpit, but I'm coming from a slalom and squirt background - is there enough footroom to use conventional footrest(s) or will it need the hole-in-a-foam-pillar approach used by custom cut squirt boats?
    Squirt? I'm building a kayak, not a semi-submerisble. But, no, there is no room for standard adjustable footrests. I'll be fitting some foam blocking left over from various whitewater boats. I'll cut it for a solid press fit so I can pull it out if need be.
    -Dave

  19. #19
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    Default Re: Tip 'n roll kayak

    I spent some time cleaning up, fairing out and sealing the inside of the hull over the past few days and then this morning flipped it over. Here's what it looks like after a first shot at cleaning up the chines and trimming the ends. I'm hoping to get an eye pleasing shape when I'm done. Nothing is far out of line, but it's not quite right, either.

    Hull flipped, initial fairing.jpg
    -Dave

  20. #20
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    Default Re: Tip 'n roll kayak

    You shouldn't have any trouble at all rolling that!

    That's a really nice photo, I like the looks of it a lot and cannot (not even trying) help thinking that 2 of those set up to take down and with a beam of about 6 feet when assembled would make a very nice and very slippery platform for fishing with pedal or electric power.

    Good job, and thank you, you've made my eyes happy.

  21. #21
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    Default Re: Tip 'n roll kayak

    Quote Originally Posted by Gib Etheridge View Post
    You shouldn't have any trouble at all rolling that!

    That's a really nice photo, I like the looks of it a lot and cannot (not even trying) help thinking that 2 of those set up to take down and with a beam of about 6 feet when assembled would make a very nice and very slippery platform for fishing with pedal or electric power.

    Good job, and thank you, you've made my eyes happy.
    Thanks. That would be an easy way to create a fishing catamaran. Pedal power would be plenty. It's both shorter and has more of a V in the bottom than either of my two current Greenland style boats. The initial stability may come in at zero.
    -Dave

  22. #22
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    Default Re: Tip 'n roll kayak

    You know of course you’re going to have to post a video demonstrating the Eskimo roll upon completion?! Can’t wait!
    Proud but humble member of the LPBC

  23. #23
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    Default Re: Tip 'n roll kayak

    Quote Originally Posted by Baltimore Lou View Post
    You know of course you’re going to have to post a video demonstrating the Eskimo roll upon completion?! Can’t wait!
    Hah. Could actually happen. My favorite demo roll (which I don't ever expect to pull off) is the candle thing. The paddler holds a lighted candle in one hand, rolls upside down while keeping the candle upright above water, switches the candle to the other hand, then rolls back up, again without getting the candle either wet or upside down. And no, there's no paddle involved. A variation involves a can of beer that is open but cannot be spilled.
    -Dave

  24. #24
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    Default Re: Tip 'n roll kayak

    Quote Originally Posted by Gib Etheridge View Post
    You shouldn't have any trouble at all rolling that!

    That's a really nice photo, I like the looks of it a lot and cannot (not even trying) help thinking that 2 of those set up to take down and with a beam of about 6 feet when assembled would make a very nice and very slippery platform for fishing with pedal or electric power.

    Good job, and thank you, you've made my eyes happy.

    Exactly what I thought when I saw this video...

  25. #25
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    Default Re: Tip 'n roll kayak

    Quote Originally Posted by Woxbox View Post

    I've decided that 9" clearance at the front of the cockpit is my limit. The feet will be forced into a toe-down position.
    Your toes may request Gurney bumps.

    gurneybumpfr.jpgDan-Gurney-Cars-003-1024x677.jpg
    ​​♦ During times of universal deceit, telling the truth becomes a revolutionary act
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  26. #26
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    Default Re: Tip 'n roll kayak

    Pigmy Boats may not be out of business. From their web site:

    UPDATE: Our Showroom is CLOSED. Kit production has been temporarily suspended. If you are interested in a boat kit you may place an order via our website. We will not charge your credit card until production has resumed and we have confirmed you would still like the kit at that time. By placing an order before then your order will be put in the queue for when production resumes.
    ​​♦ During times of universal deceit, telling the truth becomes a revolutionary act
    ♦ The further a society drifts from truth the more it will hate those who speak it
    ♦ If liberty means anything at all, it means the right to tell people what they do not want to hear
    ♦ George Orwell

  27. #27
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    Default Re: Tip 'n roll kayak

    Quote Originally Posted by Woxbox View Post
    Hah. Could actually happen. My favorite demo roll (which I don't ever expect to pull off) is the candle thing. The paddler holds a lighted candle in one hand, rolls upside down while keeping the candle upright above water, switches the candle to the other hand, then rolls back up, again without getting the candle either wet or upside down. And no, there's no paddle involved. A variation involves a can of beer that is open but cannot be spilled.
    You can replace the candle with a glass of beer. The roll can be completed with or without the paddle.
    I'd much rather lay in my bunk all freakin day lookin at Youtube videos .

  28. #28
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    Default Re: Tip 'n roll kayak

    If you agree that Woody Allen's "Sleeper" is one of the funniest movies ever, then you may understand why I found pulling the peelply off the boat a humorous thing.

    Peeling the banana.jpg

    Right, like peeling a very large banana.
    -Dave

  29. #29
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    Default Re: Tip 'n roll kayak

    But about that peelply. I've been reading here and elsewhere for some time that's its use has migrated from vacuum bagging operations to low-tech garage and basement efforts. So I decided to give it a try on this project. As one who has spent too many hours sanding and filling and fairing and sanding and filling and ....etc. ..... I think I'm sold on its value.

    Here's what the surface looks like after the peelply was stripped. This is 4 oz. fiberglass saturated in MAS epoxy over okoume ply.

    Peelply 2.jpg

    I left one section uncovered to compare. The left side had peelply, the right side did not. The peelply area actually has a bit more epoxy on the cloth, but universally even without risk of blobs or drips. So it will fill more readily. FYI, I now almost always roll on the epoxy, having decided some years ago that using a squeegee leaves too much in and on the cloth and ultimately wastes a lot of product via the sanding that ensues. For this little boat, an adequate supply of peelply fabric cost $25, which makes sense to me on an overall budget of about $600.

    Peelply 1.jpg
    -Dave

  30. #30
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    Default Re: Tip 'n roll kayak

    Sleeper, back when W A was really funny.
    ​​♦ During times of universal deceit, telling the truth becomes a revolutionary act
    ♦ The further a society drifts from truth the more it will hate those who speak it
    ♦ If liberty means anything at all, it means the right to tell people what they do not want to hear
    ♦ George Orwell

  31. #31
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    Default Re: Tip 'n roll kayak

    One more touch before flipping it back over for the deck. I had a half-roll of 4" kevlar left over from a previous job, so I ran it down the keel. This gives me some confidence that an otherwise very lightly built boat will hold up. At this point, we've just hit 17 pounds. And yes, using the peelply kept this fussy material neatly in order - especially the fuzzy ends.

    Kevlar keel strip.jpg
    -Dave

  32. #32
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    Default Re: Tip 'n roll kayak

    Thinking about putting the deck on I realized it's time to make the cockpit coaming. I had some mahogany left over from the Terrapin project and thought it would look nice. But will it bend? I tried - planed it down to 1/8" strips and heated carefully as I worked it around the form. Almost but no cigar. There was runout in the grain that I couldn't avoid. So I pulled out some Alaskan yellow cedar - excess from the last paddle. Success.

    Here's the center band glued up. I'll add the rim separately.

    Cockpit coaming glued up.jpg

    I've run into an unexpected problem here. This is an odd shaped cockpit, designed especially for ease of rolling. So the standard issue skirts don't fit. Normally, you can get a skirt made to order from Seals or Snapdragon. But Snapdragon is incommunicado these days. Don't know what's going on with them. And Seals has suspended custom orders because they can't keep up with demand for their standard lineup.

    I can improvise with another skirt until I sort this out. The problem is a Covid thing. I talked to a local dealer who says he can't get anything delivered. Last year, he sold every kayak delivered in 3 days. And then had to wait another four before the truck came back with more boats.

    So a purist would make himself a tuilik - a hooded neoprene top that fits tightly around the coaming. But I'm not a purist, and I'm not sure I want to learn how to make stuff out of neoprene.
    -Dave

  33. #33
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    Default Re: Tip 'n roll kayak

    I finished cutting out the deck panels this afternoon and placed them on the hull to have a look. This 3mm ply is something else to work with - far more pliable than I anticipated. The foredeck doesn't fully contact the hull in this shot, but when I had more straps on it it was easy to pull into place.

    Deck panels cut out.jpg
    -Dave

  34. #34
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    Default Re: Tip 'n roll kayak

    Soon we'll be watching videos of Rolling Dave! (I hope.)

  35. #35
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    Default Re: Tip 'n roll kayak

    That’s one beautiful boat. You’re a far more skillful paddler than I. I’d be stuck upside down. Looking forward to the rolling videos. Maybe I can learn a thing or two.

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