Traditional Build with Corecell

Discussion in 'Fiberglass and Composite Boat Building' started by fallguy, Apr 7, 2017.

  1. fallguy
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    fallguy Senior Member

    all rights reserved, no copying at all; there is an intentional error added as well

    here is bulkhead 2, so you guys have an idea about the hull shape, chines and such, thanks again

    [​IMG][/url]bh2 pic by fallguy1000, on Flickr[/IMG]
     
  2. Mr Efficiency
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    Mr Efficiency Senior Member

    Any sizeable discontinuity in the inner or outer skin will give a floppy structure that goes out of shape unless well supported. Glassing inside the confined spaces while on the frame will be very fruity fume-wise.
     
  3. Mr Efficiency
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    Mr Efficiency Senior Member

    And that section would not pull off the mould ?
     
  4. fallguy
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    fallguy Senior Member

    The drawing is a permanent bulkhead(BH) #2, not a station mold; one of 6 BHs in 32 feet.

    I would not install the BHs until the boat was turned; perhaps halfway for the vertical bulkheads.

    In order to develop a full traditional skeleton with all the battens/stringers over the stations; no way to install these bulkheads as stations in the mold unless you built the bulkhead at its final size and notched the bulkhead for each batten and then destructive removal of the batten/stringers and then the bulkhead would only be sort of spot welded with all the notches in it, and then you could fill all those notches with foam and retape, but then your inside tape joints would not be done at the BH unless you notched the BH at the chines as well(follow me?)...yuk

    But, it would be possible to turn the hull on the jig to 90 or 180 degrees with a good cradle and then remove 2-3 meters of mold at a time using my cleat concept (and a saw on the battens as well); tape that 2-3 meter section; install any bulkhead and continue. Perhaps it might be best to start on the transom end where you'd have a lot of rigidity in a hurry if you taped the transom inside.

    The bulkheads near the middle of the boat are 2 meters apart, so you might need to go 3-4 meters a few times to get to the next bulkhead, but you do have the removed station as a gauge of sorts if gravity starts to pull the boat sideways. I sort of assumed the boat was going to get a full flip and then gravity would be operating on the entire boat equally and the only pita is all the in and out for each BH (I have 12' 9" of headroom). I had a vision of some type of sticks holding the boat dimensionally true at the gunnels here.

    I built a canoe and I remember how floppy it was without glass in the middle, but I honestly thought this boat with only its inside joints without final tapes would be far more rigid, so this conversation has been extremely helpful. I had considered the possibility of removing mold only a section at a time already though as I was unsure about how floppy it'd be.

    I think it will be possible to do this half or full turn and remove only enough mold to install the tapes and permanent bulkheads (there are 6). I think the bhs require 3 tapes, I might only do a single tape and peelply it and finish it in the upright position. It might be possible to install some of the lockers and bases, but I had preferred to do so at full flip, however the fixed version of the boat was build with female half molds in the UK and he installed some of the stuff with the hull on its side. At some point, the boat would have enough integrity, but it would be really impossible to add the deck section until the boat was upright.

    I will have the corecell attached with raptor staples in the middles of the battens in some locations and I intend to pull those through. Nails sound better just now somehow and I was going to attach at the stations, but that sounds harder to pull apart.

    It seems like a no brainer to do a half flip; install the tapes and the BH first tapes until the boat has all its BHs in, but the boat with a full flip on the stations could also be supported from underneath and set up on its references (WL/CL/reference lines double checked) and all work done from above. If the boat is fully flipped; it'd be easier to develop a full bunk that would maintain the rocker underneath.

    The original plans are, of course, for female half molds, but I don't have the expertise of infusion in my pocket and I don't think that boat is any less squishy and floppy before bulkheads and taping of the keel is done.

    Your thoughts on a full or half flip? I like the half flip for the ease of access, but I like the full flip for making sure I have my reference lines after bunking the boat securely and tying the top for dimensional integrity at the gunnel..

    Seems like the risk of failure is greater on the side.
     
    Last edited: Apr 8, 2017
  5. fallguy
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    fallguy Senior Member

    I would only remove enough station mold to install the next bh, in case that was not made clear.

    With the boat upright; it would also be easier to install the lockers and bunk bases which also add rigidity to the hull. Easier to use a level flat than plumb.
     
  6. jorgepease
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    jorgepease Senior Member

  7. fallguy
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    fallguy Senior Member

    I have seen groper's build.

    This boat is all flat surfaces (see pic).

    I am pretty much settled on traditional jig mold; just want to work out small details on the hows.

    I can put reference lines on the station molds with 1/4" holes for lasers, flip the boat and shim to true it all back up. Remove 2-3 meters of mold a a time; keep in some cross bracing at the top, run my tapes, add a bulkhead at a time and even some of the locker and bunk bases and it should be fine I think.

    Another possibility is my cradle could be built with some lateral supports before I remove the jig mold and after shimming, so when I remove the mold; the boat doesn't settle downward at my untapped seams. I hadn't considered needing that, but it would be pretty simple to add some 2x4s to the outside of the hull in 3 places since the hull lines are all flat.

    I can't believe how much help this has been talking through it with some people with wisdom about foam. Thanks tons.

    Speaking of tons; the boat is going to be pretty heavy to flip. I was planning on using 2x12s for the strongback. I'm thinking we'll be around a ton total. It looks like I'm going to need to build a lifting system. Perhaps I should take the middles out of my stations both for access and this issue. Bilodeau makes all the stations out of 3/4 stock for this very reason, but unless they were all epoxied and even then; they might move that way.
     
    Last edited: Apr 8, 2017
  8. jorgepease
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    jorgepease Senior Member

    What if you screw corcell from outside of battens - female mold - glass inside, add your bulkheads, remove screws and flip. I think it would go faster and easier.
     
  9. AndrewK
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    AndrewK Senior Member

    I second "jorgepease", I don't see any advantage of what you are proposing over the female half moulds.
    Also question the choice of building a flat panel boat without the flat panels.

    You don't have to infuse to produce your own panels, hand laminating and a light vacuum bag is easy to do, so is infusion.
     
  10. fallguy
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    fallguy Senior Member

    So, at first when I read Jorge's response, I considered building a female full mold.

    If I build it with female half molds, it seems just as hard as building it the other way and the female half molds don't have the transom. Honestly, I went away from the female half molds because I thought it could only be done with infusion. Vacuum bagging this beast would be too hard. Too many glass areas that need to lay perfectly on the outside, all done within the working time of a single pot.

    So, for a full female mold, the bulkheads and all inside work would be done, but nothing would be done on the outside.

    Would the boat have enough structural integrity with its bulkheads and watertight compartments, locker bases and bunks and deck even to remove from the molds without any glass on the outside? It seems like there would be even more risk of deformation once I lifted this hull off the mold than the traditional way. The only way to really check the lines would be with battens and visually.

    I would really prefer to do the double layup of the bottom in single full pieces over the chines, and I wanted to put a rebate in the chines for the extra lamination there. So I didn't want to glass the panels before putting them into the mold.

    The full female mold would be possible; interestingly, upright, one could build and attach the deck on its inside seam, then when the boat was flipped, all exterior fairing would be done after the flip instead of before, so any wiggle would be faired out. Also, the boat would be removed from the mold and the new hull could be started while the other hull was still getting sanding done if I could make some space for it.

    This does sound uniquely interesting and a little easier and Richard would not have to do too much to the drawings to accommodate. There would be a lot of fumes, but nothing a fan can't handle.

    What would happen if there were no glass on the outside, but all the bulkheads and interior were done? I could probably get a layer or two on the outside of the transom.
     
    Last edited: Apr 8, 2017
  11. Beamreach
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    Beamreach Junior Member

    Introduction: ...We built two Woods Eclipse hulls on a male mold using 3/4" CC foam & 2 x 400g 45/45 bias & epoxy....
    Build has taken it's toll on time but is now back in motion -weather /injuries...

    We screwed the foam to the male mold crawling inside the mold and screwing when needed ,stapling & using wood battens to hold the strip planking .

    Fallguy your question: "What would happen if there were no glass on the outside, but all the bulkheads and interior were done? I could probably get a layer or two on the outside of the transom."

    When we flipped our two hulls glassed on one side only there was no problem.
    You would have bulk heads fitted ,thats even better ,absolutely no issues as everyone above has stated this is the best way to go!
    Great forum!
    Our only issue/mistake was storing the first hull upside down so it didn't fill with water/ice under a tarp.You have BH's installed ,solid hull relatively ,more stable than ours were when flipped....
    Jim
     
  12. AndrewK
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    AndrewK Senior Member

    A friend of mine built his boat on a full male mold, I built mine in a female half (hull only). He commented that if he was ever to build a boat again he would choose the female half mold approach.
    But for a flat panel design like yours I would do neither, build large flat panels as "groper" and build it like a kit boat.
    I had no issues taking the half hulls out of the molds or deforming while in storage with just the inner laminate and bulkheads in place, this is a 11.9M boat.
    Andrew
     
  13. fallguy
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    fallguy Senior Member

    So, if you build on a full female mold; the mold would need a break in it at the reverse chine I believe, or it would not be releaseable, right? That is just done with sistering another board on it.

    And then I saw some farriers getting built this way and it looks like a few of them were done without the transom, but wouldn't the transom be a wise way to go, but perhaps not until the end?

    Like, would you use the transom for entry or just build it all and make a moving walk to get in an out of the boat. I have 12' 9" head clearance in the shop, and there is some rocker in the boat, so there would be a few steps to get in at the transom anyhow. Seems better to build the main hull with transom and then do the guts of the boat and then flip.

    This has been an eye opener for me. I hope Richard Woods is okay with the idea because yesterday I started to see huge upside. Like my mold would only be partially removed, not fully dismantled and I would probably save weeks on setup times and checking and rechecking lines. Lifting the hull with the deck on and all will still require some specialized lifting equipment, but that is part of the fun.
     
  14. Beamreach
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    Beamreach Junior Member

    Transom is included in the mold.
    Have never seen decks built on mold ...(?)
    We used a simple chain hoist to lift off mold then carried it out over mold and out door....3 people with 4 -2x6's screwed to hull on wheels
     

  15. fallguy
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    fallguy Senior Member

    The half molds for infusion are all pressboard for the whole half, but that would be overkill for a full female mold with no intention of vacuum or infusion.

    I was thinking the bottom would be full plywood, but stations at 90mm apart would result in a lot of deflection when walking in the boat to do any work. 90mm is like ??32" or so and that is about double the typical span ratings of 3/4 ply.

    Would you guys put something like 2x4s or 2x6s on edge or whatever fit inside the mold to support 3/4" plywood? I might go plywood for easier screwing at the beginning.
     
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