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Thread: 11' Four Part Nesting Dinghy

  1. #1
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    Default 11' Four Part Nesting Dinghy

    This will be my summer project. I am kinda temporarily abandoning my last years summer project because I believe this built will serve my needs better (at least for this summer).

    I am trying to split a hull in 4 parts for easier storage and transport.



    This is my first plywood boat, I have only done SkinOnFrame boats until now (five of them). I considered doing this in SOF but I figure the main reason for SOF for me was weight. Splitting the boat in four parts will ease that problem.
    I also believe that a rigid, wooden hull will perform better?

    I am already talking to Flo-Mo about plywood building but maybe I can also ask some questions here.


    • Which wood do I use? My hull is a copy of the PT-11 (derived from anything I could find on the internet). Will 4mm ply be enough for the shell or can I use 5mm for the bottom and 4mm for the two top panels? Does anybody know which ply is used on the original PT-11? I still don't know whether I should try the cheap pine ply (37,50 per sheet) or just use Okume (55). I read that the veneers should have even thickness?
    • I guess the thickness depends on the glassing as well? Originally I started with the idea of using no glass apart from the seams but I guess I will glass inside out with thin glass. What glass do I use? Is UV protection always needed? The boat will always be stored inside and only get out for some hours at a stretch.
    • I want to try Tape&Glue. How are the panels connected? Do you sand (or plane) them to fit the flat of the next panel or just leave the edges square and fill the gap with epoxy?
    • Joining the forward and aft part does seem straight forward but would it be a problem to join the two sides under the waterline? How watertight are nesting dinghy connections. It would be nice to have not longitudinal frames that clutter the inner space of the boat. Maybe only a 5cm high "bump" to connect the halves, silicone bead or tube in a routed grove to seal it watertight?


    Thank you

    Marcus

  2. #2
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    Default Re: 11' Four Part Nesting Dinghy

    I am in the process of planning a 10ft Spindrift (non-nesting) and I intend to deviate from the plans to save weight, even if it costs a little more.
    I have calculated the cost and weight per unit area for a large number of possible alternatives to the 1/4" marine ply called for by the plans.

    I already had stock of 4mm (supposedly marine) ply and was able to get exact wood densities for my calculations-
    Some of my sheets measured 4.2mm with an SG of 0.5 (13.5lb per sheet),
    an older batch measured 3.8mm with an SG of 0.7 (17.5lb per sheet)
    The one 1/4" sample I had measured 6.1mm and and SG of 0.6 (23.6lb/sheet)

    Once the extra glass has been added (5oz each side) to the thinner sheets, the 3.8mm sandwich weighed no less than the 6mm that has only been sealed with epoxy, and actually cost more. The point is to weigh a sample sheet from each batch you consider buying if weight is an issue.

    Experimentation such as this will most likely end up more costly than other plans-built boats of similar size. Consider buying plans for something like the nesting 11' Spindrift and apply the general scantlings and construction approach to your new hull shape.
    Alternatively, or in addition to that, first start a build of a scaled down 9ft prototype out of cheap ply, 5mm on the bottom and 4mm for the rest. Assume from the outset that this will be a disposable proof-of-concept. This mindset will greatly reduce the time you end up spending thinking and wondering about a particular solution or building approach. It will allow you to test your panel development and give you a "feel" for working with ply.
    Try as many "what-if" ideas as you please, even if it is quick and nasty. The aim is to boost your learning curve and find out what works.
    Try different methods of stitching, i.e. wire, zip-ties, duct tape. Start by first just glass-taping the seams and sealing the remaining surfaces with epoxy (you want it to last at least long enough for some sea trials). After testing your nesting connections and seals, add some glass to the bottom, outside only at first. Test and compare weight and stiffness with what it was before.

  3. #3
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    Default Re: 11' Four Part Nesting Dinghy

    I agree that what you are proposing is pretty experimental and would benefit from a throwaway proof of concept. Totally worth a try though.

    My first prototype boat was based on a similar concept (not nesting per se, but it has a front and rear half bolted together in the middle). The "bump" I used in the contact area was a lumber/plywood partial bulkhead on each half, that was between 10 and 12 cm tall. You probably want at least 8 cm tall and nearly 2cm thick on both sides so that the sections can be connected with some pretty serious bolts (at least 5 mm diameter). Softwood is ok for the "bump wood", doesn't need to be hardwood, but ply might be too flimsy. Flat bottom would be easiest because V-bottom would require beveling. The bow might end up a little bit blunt.

    I wouldn't use silicone or any kind of caulk in the connections, but a gasket of neoprene or some other type of rubbery closed cell foam that can be partly compressed by the bolts to give a good seal. My boat wasn't designed to be taken apart, so I taped a heavy duct tape over the crack on the outside. The connection has never leaked a drop, but a little bit wouldn't matter anyway. If you beach launch or use it in rain or waves there will be a bit of water in the boat.

    If you are doing a really rough throwaway prototype, don't even bother epoxy sealing or painting anything and maybe even clamps would be sufficient to hold it together. I found that even non-waterproof plywood can be immersed a good number of times before it delaminates if it doesn't sit wet for too long. I had "waterproofed" my exposed plywood surfaces with a water resistant outdoor white wood glue (not titebond 3) and I used the prototype for several months without any problems. Only after winter storage in a non-ventilated tarp did I encounter issues of minor delamination and mold on the surfaces and chose to varnish the thing to get another season out of it. I'll soon take it out of its winter tarp again (this time vented) and wonder how it fared this time. I'm guessing the glue in the plywood (lauan underlayment) is animal based and good mold substrate.

    If you expect your boat to last one whole summer or maybe two and it is always stored inside, I would paint or varnish it with several coats, but wouldn't bother epoxy coating or even glassing it. Whoever suggested that unglassed but slightly thicker plywood might end up both lighter and easier on your wallet are probably right. The pine would be fine if it bends well enough, has no glaring defects and the glue is waterproof. Bronze fasteners would be overkill; but stainless would be a good idea.

    I hope you won't mind the time it takes to carry each part to the water and bolt it together and then unbolt it every time you use it. My prototype has removable rowing outriggers that I have to bolt on and unbolt each time and found it to be very tedious even though it was just two bolts on each side. I used wing nuts so I didn't need any tools. The boat I'm building now is wide enough to not need these. It will need some side extensions on my car roof rack though to accommodate the 1.28 m width. A little cart can make getting a one-piece boat around much easier and I plan to build one.

    Also give some thought as to what kind of seating arrangement would work with all the connections. If you intend to sail it, the sailing bits would need to be off-center and it adds another layer of complexity.

    Don't expect a little 11ft nesting boat to be a performance winner. You may not even get the desired rigidity but a prototype would tell for sure. If extra rigidity is required, you could probably fabricate removable gunwales held in place with rope, cable ties or some sort of snap-into-place system.

    I don't know what performance aspect you didn't like about the SOF boats but if you post some pictures and what exactly you are hoping to improve upon, someone on this forum may have some good alternate suggestions.

  4. #4
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    Default Re: 11' Four Part Nesting Dinghy

    This will be an experimental boat for sure.

    Here is my SOF pram
    http://www.imagebam.com/gallery/32sf...5b2sgpntux5f48
    I guess it was not the technique but rather the whole boat when I was talking about performance. I just hope to get a better performing sailboat with my PT11 clone.
    Do you believe changing from SOF to plywood is unjustified?

    I now know that the PT11 uses 6mm Okume in the hull.

    The sailing bits should fit between the hull parts with the centerboard right in front of the dividing bulkhead.
    The mast step will also be in two halves. The mast s going to be bamboo poles again but in sections (connected with composite tubing.). Sail just Tyvek again for testing.

    The bulkheads and both sides of the facing, longitudinal members will be 12mm phenol coated ply like in all my boats.

    I intend to sit on the bottom.

    The seal I was thinking about are silicone tubes that should seal really well in groves with even thickness and they do not have a memory effect.

    I will use wheels to get it to the water, the segments are only necessary for transport and storage. The back of my Sharan ist 114*100cm and 200cm long. My design should fit a box of 100cm*55*177cm.
    I also couldn't get one half down in the basement...four parts work. (A kids canoe is already hanging on the wall).


    For construction it would be nice if I wouldn't have to join the panels to cut them apart again afterwards...
    I already had the idea of a negative mold for my folding boat last year. A cheap, negative plywood (or Hartfaserplatte? How do you call the back material on Ikea furniture? ) mold would give me the ability to weld a PVC tarp for covering the hull inside.
    Here I could assembly the plywood boards inside without taping or stitching.
    Could also built a SOF version and a ply version in the same mold.

  5. #5
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    Default Re: 11' Four Part Nesting Dinghy

    The pram looks nice, what do you not like about its performance? Does the transom bow kick up water? Does it twist and groan under sail? If it is just too slow, could that be because it is so short? Did you properly shape the sail? Could the sail be too small for the amount of wind you have? Is going to windward too hard? Is it too unstable without ballast?

    I don't sail, so I have no idea which would be a better boat or if one building technique makes better sailboats than the other.

    I'm just brainstorming techniques and possibilities here (have never built a boat in 4 quarters but it sounds like a fun challenge). This boat could probably be built successfully in several different ways.

    Building the outside of the boat and then installing the bulkheads and cutting the boat apart may be best, who knows. Is that what the PT 11 calls for?

    If it were me I'd probably start to build each section individually without any kind of mold because it worked for my 2-section prototype, but I would use one for putting the sections together. In a stitch and glue boat the panels define the shape, and you want to cut your panels as accurately as possible. It is best to cut the left and right panels at the same time so they are as equal as possible. The curves will define themselves by the shape of the panels and even if your cuts aren't 100% accurate the structure will be mainly self-fairing. I was very pleasantly surprised the first time I went from a cardboard model to actual plywood; it bends more evenly and holds it shape much better than cardboard. Even if a mold isn't always strictly required, some stabilization like a cradle/female/negative mold is definitely good and the need for it goes up as the boat gets bigger. Right now I'm building a 2.5m long stitch and glue boat just sitting on some milk crates, no mold or cradle. My other boat in progress (4m long) is sitting on a very crude cradle right now but I wish I had made a better one.

    The Hartfaserplatte (fibre board might be an ok translation to English, I forgot the more specific term) would be ok in principle as a cradle material but if it is as thin and floppy as what's on the back of Ikea furniture it will need some serious stabilization with something more solid. Something like the front of an Ikea bookshelf would be better (12mm thick would be perfect), doesn't need to be anything expensive as long as you can make clean cuts and the edges and corners don't crumble. Most of the pieces of the mold/cradle should go across the boat and once you have these in the right shape attached to some sort of a strongback you'll figure out if you need something longitudinal as well. Stacking pieces together in waffle/egg carton fashion might work. There needs to be something solid underneath the area were all 4 quarters join. You have to still be able to get close to the boat to work on the inside. I don't understand at all what you were planning to do with a tarp as part of the mold setup.

    I would probably stitch the quarters separately, starting with the corner where the longitudinal and transverse bulkhead join the bottom in a right angle corner. Do what you can to make that corner exactly square, and then stitching together the rest. Then put the stitched sections right side up into the cradle and line them up and straighten everything along the bottom. Then you can clamp the bulkheads together and add a few spreaders across the top that will hold the sides at the correct bream. A temporary set of gunwales clamped on will further hold the shape and then you can fillet and tape the inside seams. Once that sets, each quarter will probably be rigid enough that you can take the thing apart to tape the outside seams, or you can turn the whole thing over, clamps and all, and tape the outside seams (except for the ones you want to take apart).

    The idea of using solid softwood for the bulkheads came to me because it is rigid and not that heavy. Real wood works really well for using screws to stabilize the sections, and getting the transverse and longitudinal bulkheads exactly square to each other is important. You would have to probably join several pieces at the bow curve and might still get some cross grain there unless you laminate a stem or use plywood in just that area. The 1/2" ply is probably solid enough but won't hold screws into the edges well, so you have to join the bottom and sides to the bulkheads with stitching, filleting and taping instead of "screw and glue". If using softwood you could install the bulkheads as a clamped unit into a male mold then screw the quarter sections of the bottom down onto them, then flip the whole works and add the side panels.

    If the silicone is shaped like a tube (basically a hose) that's probably ok. I was thinking you meant the silicone caulk that you squeeze out of a cardboard tube to seal around a bathtub. The tubing/hose you can replace if it doesn't work but silicone caulk is difficult to remove.

    My first real build was an SOF kayak and I found I didn't learn much about plywood stitch and glue by building SOF. Everything will become clearer once you start and you might totally find way of doing everything that is completely different from what I proposed. Flo-mo is probably full of ideas as well and he has more stitch and glue building experience than I.

    The designing, experimenting, head scratching and trying something new, making mistakes and figuring out how to fix them to me is about half the appeal of boatbuilding (the other half of the fun is testing out the boat in the end to see which ideas worked). I would probably find it too boring to build two boats of the same boat model in a row.

  6. #6
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    Default Re: 11' Four Part Nesting Dinghy

    It is sailing like a little fat pram is expected to sail...maybe even a little more lively because it is really light and I can drive it @8kmh against the wind with the Mirage drive.
    With the PT11 I hope that I can sail faster. Also more often because it will be easier to get in the water alone. Also planning a bike trailer.

    With the female mold I was talking about my last project which would have greatly benefited from that approach.
    http://www.imagebam.com/gallery/njq1...d24928cegwm239

    http://forum.woodenboat.com/showthre...iff&highlight=

    If I had built it in a mold I could have welded the skin inside of it and could have done the lamination of the frame by just using cable ties to fix everything to the mold.
    I am still planning to do this when I have more space. That way I could rebuilt a part when one thing is not good on the boat.
    That is more important for the folding boat if course.
    I plan on continuing the folding boat adventure...but not this year.

    I am back at drawing. I hope to start building in the next weeks.

  7. #7
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    Default Re: 11' Four Part Nesting Dinghy

    The PT 11 hull is all 6 mm Okoume, but we calculated that if just the upper 2 panels (more than half of the surface area) were 4 mm, then we could lose 11 pounds. The bottom panel at 6 mm is about as light as it should be for walking in, although the skeg stiffens the part that is walked on.
    Splitting the two halves on the centerline seems really challenging. Have you considered 3 parts that all fit into the center part? With your CAD skills, maybe you already have explored that.

    Russell

  8. #8
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    Default Re: 11' Four Part Nesting Dinghy

    Hi Russell,

    Love you!!

    I actually tried 3 parts but abandoned it.
    3 parts wouldn't fit my trunk but 4 parts does work quite well and I might even get it in the car with the seats in and my 3 boys can come sailing too
    It will even fit between the metal loops on the sides that restict the 114cm to a little over 100cm!
    http://www.imagebam.com/image/22bb2b550405227

    Just split it right in front of the daggerboard and divided each half again.



    Then I stacked it with some room to spare and let Rhino draw a bounding box around it.
    Glad to say you could ship a 4partPT11 in a box no bigger than 1250mm*900mm*1000mm.

    I also found a way to fit it in an even smaller box as you can see in the last picture but that involves stacking the parts against each other. I would have to slide all four parts in the trunk at once....would work for shipping though.

    I am getting the parts cnc cut in cardboard and will do a full size prototype. That way I can glue in knees and other parts to see if it still nests. Time to get away from the computer and get dirty.

    Marcus


  9. #9
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    Default Re: 11' Four Part Nesting Dinghy

    That's to scale.


  10. #10
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    Default Re: 11' Four Part Nesting Dinghy

    Interesting stuff, looking forward to seeing how the CNC prototype works out!

  11. #11
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    Default Re: 11' Four Part Nesting Dinghy

    The cardboard 1:1 mockup was fun but I had my old file/plan (it's also 20mm off the original lineplan...the new hull only deviates about +-5mm from the original) cut which was intended for the other split so it is missing some bulkheads and the middle one is split just like the forward bottom blank.
    I also had no clue about cardboard and got the heaviest for the bottom and the bulkheads. That's a double wave with a sheet in the middle...like 8mm thick. I had tabs drawn and market but it would not really fold. I installed the longitudinal member to get some rocker forward but did not do so aft which I did first....might do that since I got 3 of these pieces unused now.

    I will try another one with all parts made from the heavy stuff.
    At least I have a feeling about the size now.
    Might not last that long if the kids are getting up early tomorrow.

    The white sides look nice but the cardboard is too thin. The forward part is still a little floppy because I didn't bother to install the second frame. I definitely need to try that again with the right model.

    Not great but I just link to the gallery, guess some would like to see how a big paper PT-11 looks...

    http://www.imagebam.com/gallery/pyqx...9yftouqad6416u

  12. #12
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    Default Re: 11' Four Part Nesting Dinghy

    For the cockpit I imagine something like that:



    Some pipes (glass, Kevlar, PE or wood) for structure and latch clamps for quick assembly. Maybe another latch clamp below the gunnels.
    The seal is a silicone pipe, maybe some bed and cove to the mating faces but I need to do some more thinking on that. I'd rather have no lip to damage if a simple seal will do.
    For the other two joints I could use normal bulkheads, latch clamps above the waterline and also some pilot pipes to fit everything together and give the joints some more strength.

    What do you think?

  13. #13
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    Default Re: 11' Four Part Nesting Dinghy

    I did the joint with flat panels so it doesn't fit the hull perfectly for now...also didn't bother with the texture. The pine will look poor anyways.

    I am a little out of ideas for now. Might just start glueing together the basic hull, doing foils and other stuff.

  14. #14
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    Default Re: 11' Four Part Nesting Dinghy

    I really look forward to hearing how this works out in the water, and maybe even turning into a retail product. Anyway I have an idea so crazy that you needn't reply about it's unsuitability. It's about reducing your structure for mating, latching, and daggerboard well for a rather radical drawback - bolt on fins.

    I have a strange little sailboat that has 2 rectangular fins that bolt on to a selection of 3 locations along the centerline keel. It occurs to me that you have 3 mating seams under tension and such fins could bridge the gap and reinforce. The daggerboard well could be eliminated and the flat mating plates could be scooped lower giving more open space.

    The obvious drawback is not as bad as I feared, at least for a beach launch. I rig everything but the fins, then put the boat on it's side for fin attachment. I slide the tipped boat into the water by standing where the nonexistant jib would be and pull the mast. With multiple fins the draft is small enough that I can upright the boat quickly and sail shallow areas like almost no other sailboat (we have a lot of reef shallows). However the shallow fins do suffer leeway when the waves are high.

    P.S. nesting boat compartments can be hard to bail water out of, if not designed for it.
    Last edited by rudderless; 05-29-2017 at 07:00 PM.

  15. #15
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    Default Re: 11' Four Part Nesting Dinghy

    Good thoughts.

    I got a kayak with 4 screw on fins.
    I guess the beauty of this design is that I could try alternative sections and just switch back to the original centerboard case of that doesn't work.

    Thought a lot about the connection system. Forward I am now leaning toward 4 big holes with 90 twisting doublewashers with keys....like the twisting caps in inflatables?
    Or a keyhole type with a nut that gets inserted, slides down in the slot and is then closed with a quick spanner.
    I will chose the least expensive and simplest solution I can find.
    In the cockpit, the aft parts connection is still open for debate.
    Ordered 5 pcs 100kg latch clamps and will try when they arrive from China.
    Another idea would be to insert aluminum (rectangular pipes?) And clamp them with a twisting cantilever so that they are lock and structure in one part.
    Any ideas and drawings are welcome.

    Any ideas of a bigger sail would help in any way? Not much wind here most of the time.

  16. #16
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    Default Re: 11' Four Part Nesting Dinghy



    Scarfed the panels. I planned an edge on the transome for glueing it to the panels. All the edges of the transome are cut at an angle according to the 3D drawing.

    How wide do you space the holes for the zipties? How many mm are they from the edge? Got 6mm ply for the bottom and first panels, the upper panels are 4mm
    Any tips for stitch and glue? It's my first S&G boat.

    My sail cloth arrived today, ordered it on Wednesday.
    It's 152cm wide, completely white Tyvek. 12m, enough for a spinaker
    Also got some silicone tube from China today, orders that one 4 weeks ago. Still waiting on the latch clamps. I might end up building wooden clamps.

  17. #17
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    Default Re: 11' Four Part Nesting Dinghy



    More photos.

  18. #18
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    Default Re: 11' Four Part Nesting Dinghy

    For 4mm panels I use thin steel binding wire (it is either 0.7 or 0.9mm - will have to dubble-check), spaced approximately 6" apart depending on how much load there is on the stitches. I normally drill a 1.5mm hole about 8mm from the edge.
    I used cable ties on a previous kayak build, found them fiddly to intall and they require much larger holes. If you over-tighten them you have to cut and replace with a new one. With wire you just untwist as required. Wire can also be pre-bent to help feed around corners.

  19. #19
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    Default Re: 11' Four Part Nesting Dinghy

    Any ideas on the sails? I got a 1.5m wide roll of printless Tyvek.
    Is it possible to get any cut into Tyvek? I just like it because it is cheap, light (50g/m) and I can get it. Maybe I'll have a sail made later but for now a 4.20m bamboo poles and the Tyvek will have to do.
    Any thread on cutting sails that I will help?

  20. #20
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    Default Re: 11' Four Part Nesting Dinghy

    50g/sqm sounds very light. That is around 1.5oz/sq-yd. My Spindrift 10ft dinghy plans call for 4oz.
    I don't have any sail-making experience, but have read that Chinese Junk rigs allow lighter than usual cloth due to the even distribution on sheet loads to each batten.

  21. #21
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    Default Re: 11' Four Part Nesting Dinghy

    I have made a successful sail from blue tarp and clear duct tape. It's only good for a season, but quick and cheap to build. I have seen tyvek sails, but not built one. I'll bet an internet search for tyvek sails might yield good results. I used books by professionals to design the tarp sail, primarily Bradshaw's Canoe Rig, and an old pamphlet on homemade sails. Shape was achieved by cutting darts. There is a guy who builds tarp sails, he probably has a website with some DIY instructions.

  22. #22
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    Default Re: 11' Four Part Nesting Dinghy

    When I google tyvek sail, I see many threads both in and out of this forum, including do-it-yourself. Of course google probably tailors searches differently between us.

  23. #23
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    Default Re: 11' Four Part Nesting Dinghy

    Already did a Tyvek sail but thought some might have some advice on how to cut the PT-11 sail from Tyvek.

    Home again since yesterday and made some progress.

  24. #24
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    Default Re: 11' Four Part Nesting Dinghy

    Looks good.

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    Default Re: 11' Four Part Nesting Dinghy



    All bulkheads dry fitted and screwed in. Need to take them out and get them in their final shape before glueing them in.
    I actually bought some finished wood for the rails. Needed to clamp it on for fitting the cockpit framing. Now the sheerline looks much better than before.
    Next I'll take everything out again, sand the inner hull, glue parts in, tape the inner seams and glass the outer hull.
    I got a little mixed up, don't really know what to do first. I wanted to have everything in before doing the seams. Also all the parts need to be correct in the millimeter, I take all measurements from the cad model.
    Also need to do the stem.
    The original got a cnced stem but I guess I can do that on the bandsaw. The round bow of the PT-11 does look sexy.

  26. #26
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    Default Re: 11' Four Part Nesting Dinghy

    One bulkhead in, transome in, one cockpit divider in.

    I only got 1m*1m glass, 250g/m.
    Do I need to do the seams with tape inside or will it work if I glass it right away? I want to do glass the outside and completely glass the two cockpit parts. Only the seams forward inside.

    How much epoxy will I need for 10m?


  27. #27
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    Default Re: 11' Four Part Nesting Dinghy

    I have always used a rule-of-thumb of 200g per sqm for initial wet-out and then add the same weight of epoxy as the glass density.
    The latter can vary depending on how much you need to fill the weave if any.

    If it was my boat I would tape the seams as well just for peace of mind, unless the original PT or similar existing designs show that it is unnecessary.

  28. #28
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    Default Re: 11' Four Part Nesting Dinghy

    Initially I only wanted to tape the outside seams but I guess weight isn't much of an issue as long as any individual part isn't much heavier than 10kg.
    Also found more, lighter glass (120g and 160g maybe, was for a bisected surfboard built) in the basement (wrapped in Die Welt, dating June 2007) which I might use on the outside.

    Today I finished the second double frame, then I went and bought a second battery Multitool (my other one doesn't have quick tool change).
    Glued in the frames and the cockpit framing.
    Next I will put in some 45 pieces to merge the cockpit framing into the hull and than glass the two cockpit parts inside.

    Don't know if I will paint the boat for now.
    The foils will have to wait till I can CNC them...just boards will do for the ruder and daggerboard for now.


  29. #29
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    Default Re: 11' Four Part Nesting Dinghy

    Now I will glass the inside, maybe finish the interior and inner gunnels, then cut it, assemble it and finally glass the outside.

    It's heavy...but then I am only used to skin on frame boats.


  30. #30
    Join Date
    Apr 2012
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    412

    Default Re: 11' Four Part Nesting Dinghy



    I've glassed the stern part with 2m of 280g glass. Took almost 700g of epoxy.
    The bottom panel is double glassed with the overlaps on the first seam.

    I think this is overkill. Probably only glass the seams of the other parts and just coat the rest with epoxy.
    Don't know what to do on the outside. Maybe a layer of lighter glass or just glass the bottom panels and only the seams above the waterline.

    How do you normally do this? Now I can still see the weave in the inside. Do you coat it again or just sand it a little and paint it? Do I need to paint it or can I just sand it a little and leave it be?
    The boat will only stay in the water for some hours any day and won't be exposed to sunlight longer than that either.

    When I use the heavy glass on the outside, how do I smooth it or am I not supposed to see the weave after glassing?

    I guess next time I'll try the same exercise in SOF, kinda hate glassing, it's rather expensive and I am not good at it too.


    http://www.imagebam.com/image/f49a98571097913

    That's Ikea oak...used drilled holes, routed the holes with a roundover bit and cut small blocks for the inwales on the circular saw.

    http://www.imagebam.com/image/fd9418571098363

    http://www.imagebam.com/image/32b760571099023

    Also did this for the bow.

    http://www.imagebam.com/image/bf3928571099533

    Had to put the epoxy on ice and do two batches to get the riser blocks mounted with the help of my wife today. 40C outside.

    http://www.imagebam.com/image/f84949571099853

    Here's my whole gallery.

    http://www.imagebam.com/gallery/pyqx...9yftouqad6416u

  31. #31
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    Apr 2012
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    412

    Default Re: 11' Four Part Nesting Dinghy



    I've ordered 5m 160g glass, got another 5m in my stash. That will go on the outside.
    Also ordered another 6.5kg Epoxy.

    Just glued in the inwales in the aft half of the hull.
    Will probably do the forward half when the epoxy is hard, not enough clamps for both parts at once.

    I am contemplating to foil the outside. Saw a mirror finished tri hull done this way on duckworks some weeks ago.
    Any thoughts on that?

    The last photo are the inwales from the forward parts standing like the parts will go in the car. Can't wait to see if it fits

  32. #32
    Join Date
    Apr 2012
    Posts
    412

    Default Re: 11' Four Part Nesting Dinghy

    I am revisiting the idea of adding a rectangular aluminum tube on the bottom, right below the skeg.
    Also a flat rectangular tube right below the rail, on the outside, so I can slide a bar in to fit the parts together.
    I am not confident that the latch clamps alone are enough to align and secure the aft parts together.

  33. #33
    Join Date
    Apr 2012
    Posts
    412

    Default Re: 11' Four Part Nesting Dinghy

    Just bought 1m 12mm aluminum tube and 10mm aluminium rod.
    3*20cm will go on the bottom panel, all aligned with a board while glueing, a 10cm tube on the inside below the wales.
    If they don't work I will cut them off and glue them to the outside of the hull.
    I hope that's enough to keep the boat together combined with the latch clamps.
    When it doesn't work I'll glue in some blocks with nuts and just screw the parts together.
    I'll just take a drill with me for quick assembly

  34. #34
    Join Date
    Nov 2016
    Location
    honolulu,hawaii,usa
    Posts
    118

    Default Re: 11' Four Part Nesting Dinghy

    Quote Originally Posted by heavyweather View Post
    I am not confident that the latch clamps alone are enough to align and secure the aft parts together.
    The Reverso Air is very similar to your design. It may be instructive to view all dozen or so of their videos, including wooden prototype and many methods of clamping 4 glass sections together. Finally they seem to use clamps at the top and 2 tension straps (doubling as hiking footstraps) at the bottom. Other versions had 1 strap on the floor or an upper strap on each side. I want one, but yours will be lighter and cheaper. vid:


  35. #35
    Join Date
    Apr 2012
    Posts
    412

    Default Re: 11' Four Part Nesting Dinghy

    Wow. Why did I never see that before!

    I did a mock-up of the clamping part. Now I am more confident that it will work with a short rod in the skeg and one 10cm tubing just under the wales.


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