(strip)planking a Wharram TEHINI ?

Discussion in 'Multihulls' started by Islander63, Jun 15, 2022.

  1. fallguy
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    fallguy Senior Member

    As a point of clarity, I did not advise building in a shipping container, but making one into a climate controlled building. Two 40' shipping containers kept 30 feet apart can be made into a superb building with a hoop tent above. I believe some kits are available even, so for less than 10k, you can build a climate controlled storage and a carport to work in shade. All your smaller work like lids and such could be done in climate controlled area if you did it well.

    Rob's idea of half shells is how the Skoota was specified, but I got nervous about 34' infusion and did the horrendous task of wetbagging 34' panels instead. In the tropics and above 75F, forget wet bagging. Infusion is more practical, but you need good support on how.

    Half shells are probably the only way I'd do foam there after building a much smaller cat. Gotta keep them dry until they are sealed up..again, a shipping container 40' long would get you close if the shells were not too wide. Four half shells and you set them outside and build the guts and the boat would get closed up fairly fast..

    Should add, I can't help with how, but this is the direction I'd take even if I restarted my own work today and especially for foam in the tropics. Denney's wealth of experience is something I'd fall back on if I went with the proa concept. So much depends on mooring costs here. Keeping a 50' x 24' boat where I live is too expensive for annual slip fees.
     
    Last edited: Jun 19, 2022
  2. rob denney
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    rob denney Senior Member

    The site works for me. Maybe try a different browser? Or just ask me questions here and I will answer them.

    Did this page work? http://harryproa.com/wp-content/uploads/2022/06/C50-General.pdf.

    If you use containers for a shed with a cover, get side openers rather than end openers. Prices have more than doubled for containers in the last 6 months or so, the longer you can wait, the more chances they will return to normal.
     
  3. Rumars
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    Rumars Senior Member

    Foam will not be cheaper to ship then plywood, weight doesn't matter, volume does. The economy of ply vs. foam depends on local market conditions, every location is different. The most economical way to build with foam is using polyester, but the outside skin can be done with vinylester for better protection.

    Building with wood out of a container under a tarp is entirely possible. Just keep the wood in the container and run a dehumidifier.
     
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  4. rob denney
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    rob denney Senior Member

    If you have a mould for a heavy design, polyester is great.
    Polyester requires csm mat between layers. The cost of this, and the extra resin it requires goes a long way towards negating the cost advantage over epoxy on a multihull. Add in the extra sail area, motor size and reduced payload the heavier boat requires for the same performance and it may not be cheaper.

    Resin and or glass shipped with the foam makes the shipping cost weight based. If the maintenance costs and extra build time are included, ply is rarely cheaper.

    I have just had a quote for 10mm and 20mm PET foam: $4.50 and $9.50 per sq m. I doubt you will get marine ply, or even exterior ply for this price.

    Dehumidified wood must be coated with multiple coats of epoxy before being exposed to high humidity. The are many examples of strip planked boats glassed on the outside on a dry day twisting and warping on a wet day before the interior has been glassed. Much more a problem with soft wood than hard wood, but not many multis are build from the latter.
     
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  5. fallguy
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    fallguy Senior Member

    @rob denney

    How are you building the ends of the proas? Are they nosecones?

    It was rather difficult to do my single axe ends on my cat, and in the harry may have 4.

    I am just thinking about tabbing the inside versus moulding it.
     
  6. rob denney
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    rob denney Senior Member

    There are 2 options on harryproas. Both have a strong watertight bulkhead near the ends. They won't apply on boats with structure on the bows (beams, forestays, anchors, prodders).
    One option is solid polystyrene foam for'd/aft of the bulkhead sanded to shape, then glassed onto rebates in the hull sides, deck and bottom. The shapes are included in the plans. Fairing is minimal due to the rebate. After the first one, this is a pretty easy, albeit dusty and sticky job.

    The alternative is to carry the shape and the hull join rebates all the way to the bows in the mould and include it in the infusion. The bow rebate is also included as above. The hull is joined, the bows are cut off, filled with foam, the bulkhead installed and the bows glassed back on. Sounds more complicated than it is, the plans take you through it step by step.

    The important thing is to have the bows not connected to the rest of the hull. Otherwise, in a collision, a) you may reduce the integrity of the hull and b) the shock wave travelling down the hull may pop the hull skin off the bulkheads. Both the arrangements above prevent this happening and also act as a cushion to slow the deceleration in an impact.

    Hitting something at 20+ knots in a boat without a cushion on the bow or that has fixed rudders or daggerboards is a recipe for a serious injury to anyone not strapped in. It is weird that people sleep feet forward in cruising cats to avoid damage from impacts but are not concerned about standing up.
     
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  7. Islander63
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    Islander63 Junior Member

    Nope Does not work. Tried other browsers, googel searched it, changed my DNS settings accordingly nothing.
    But what makes it really strange is that Kurt Hughes website Multihulldesigns.com also does not work.....
    Must be some kind of conspiracy against good designers !!
    In the meantime i tried to get to know more about intelligent infusion via other websites. I must admit in the beginning i looked at some pictures of panels being infused, and thought this is nothing for me. All these pipes and plastics everywhere... Looked to me like a body on a operation table. A bit like Dr.Frankenstein.
    But i can see now that this must be the way to go for me here. think it`s just a matter of adapting, and learning. As Fallguy so wisely advised, some good support on how to do it right, is essential.
    It is a shame that i cannot enter your site. I`ve been trying to find more info on Harryproas, but mostly just some pics and not much detailed info or specifications of your designs. From what i could find, i would be interested in your newer concept, such as the C50 +C60 and the cargo proas.
    I always had the idea to combine my need for a live-aboard for me and my wife, and a way to make a (small) income with it. Cargo, but than in a most sustainable way, had my preference above charter or fishing. I remember that i could not find a design with a possibility to combine Live-aboard and cargo. Most catamarans u can build have not enough payload, and would lose it`s ability to sail proper even when loaded to the max. that the designers advised.
    With your cargo proas, it could well be a feasible option for me here.
    I will try later, on another device, to open your site But if it still does not work, would it be possible to send for instance the pdf file in link you send to my e-mail address (janseychelles@gmail.com) ? I can see no other way for me to get the info i would need to judge, if and witch model would fit my needs.
    My mind is now set on harryproas "Keep Shunting" (lol)
    I would really appreciate your cooperation.
    Thanks, islander63
     
  8. Islander63
    Joined: Jun 2022
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    Islander63 Junior Member

  9. fallguy
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    fallguy Senior Member

    The site loads for me if my phone doesn't have many tabs open; otherwise I get nothing.

    if your provider is blocking it; perhaps Denney can email it
     
  10. redreuben
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    redreuben redreuben

    Works for me, opens in a snap.
    iPhone XR
     
  11. rob denney
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    rob denney Senior Member

     
  12. rob denney
    Joined: Feb 2005
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    rob denney Senior Member

    I have sent you the pdf. Please let me know if you can't open it or have any questions.

    Intelligent Infusion is a bit different to what is shown in most videos. The object is to make it as easy as possible. We limit the number of pipes and plumbing generally. Most jobs have a single inlet, a length of spiral, bleeder or slots in the foam and a string around the edge. A big part of the enjoyment I get from designing boats is discussing them, so feel free to ask questions.

    The cargo proa (can you open this link?) is a prototype, it will almost certainly evolve. At present it would only work as a cruiser for people who don't need much space or stuff and who can appreciate/live with a 24m/80' lee hull.
     
  13. Islander63
    Joined: Jun 2022
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    Islander63 Junior Member

    Yes, Rob. Thank you. I think it was a link to the PDF file on https://drive.google.com/file/ etc. This works but anything starting with harryproa.com not. ??? I`ll find a computer geek to sort this out. As i would Need more info especially about your infusion methods etc.
    I will send you an e-mail later with more details of what i am looking for, and need to know.
    All I want to say is, that it's true, as so many people on this forum already know, you are a very accessible designer and an "easy" person witch does not make you feel uncomfortable asking (amateur) questions.
    Thank you for that.
    Regards, islander63
     
  14. rob denney
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    rob denney Senior Member

    You have exhausted my computer knowledge, but there are plenty of helpful computer whizzes on the harryproa chat group, (HarryProa groups.io Group https://groups.io/g/HarryProa) along with a lot of expertise on other stuff. Current discussion is about identifying stuff in the water ahead of the boat to avoid collisions.
    Look forward to the email with your requirements and thanks for the compliments. It is easy to be helpful when the people asking are pleasant.
     
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  15. Islander63
    Joined: Jun 2022
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    Location: Mahe, Seychelles

    Islander63 Junior Member

    I have decided not to build with wood of any kind here in the tropics for mostly all the reasons you all have mentioned in all previous posts.
    And i`m grateful to all of you who took the time to listen and answer my questions. Very helpful and most probably prevented me to get in to all kind of problems.
    I think this thread could be closed, and i should start a new one. Good design for foam core 40+ft. ??? or something like that.
    Again thanks to all, for your contributions !!
    Islander63
     
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