Stranded bamboo planking

Discussion in 'Sailboats' started by Sharp, Apr 21, 2021.

  1. Sharp
    Joined: Apr 2021
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    Location: South Carolina

    Sharp New Member

    I am looking to build a modified Mash-up of a sharpie/i550 as a first sailboat. I have been looking into construction materials and it occurred to me that solid stranded bamboo flooring might be a great material to use, if epoxied and glassed, due to fiber direction, strength, and hardness. I’ve done a few soaking/submersion tests, and while ends will saturate there seems to be little swelling (less so than pine, etc.), and a relatively quick return to original state once dried.

    I would very much appreciate substantiated opinions and information from any and all with experience on using compressed solid stranded woven bamboo in this capacity.

    The only immediate concerns I can identify is weight as it seems significantly more than most other wood products at approx 3.23 lbs sf at 1/2” thickness, and determining if epoxy can bond to the aluminum oxide finish, or if it would have to be removed prior.

    Very appreciative of discussion, and fully aware that someone will undoubtedly ask “but why”.
     
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  2. Blueknarr
    Joined: Aug 2017
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    Blueknarr Senior Member

    Welcome

    The bamboo composite I'm familiar with use urathane as a resin and finish. Epoxy should bond well.

    But I have only seen it in lengths less than a meter. That's a lot of scarfing.
     
  3. Dejay
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    Dejay Senior Newbie

  4. Sharp
    Joined: Apr 2021
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    Location: South Carolina

    Sharp New Member

    Thanks for the replies so far. I am actually looking at woven stranded bamboo which is compressed with apparently a urethane binder. It is dense and harder on the Janka scale than oak. The material density is approx 77 lbs per cf.

    I agree on the need for a lot of scarfing for long boards, but have a couple ideas around this too.

    I was thinking the attributes might be exceptional in creating framing specifically.
     
  5. DogCavalry
    Joined: Sep 2019
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    DogCavalry I aim to misbehave.

    I'm curious. Please keep us posted. We are all here to learn.
     
  6. Old Stoker
    Joined: Feb 2020
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    Old Stoker Junior Member

    Have a look at Bamboo schooner on you tube. The construction techniques are interesting. What about double diagonal, epoxy ?
     
  7. Sharp
    Joined: Apr 2021
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    Location: South Carolina

    Sharp New Member

    Thanks for the recommendation! Checked out the bids but don’t see anything specific to this material or an equivalent.

    Being that my goal is to develop this off of a combination of attributes from the sharpie, i550, and i650 designs I believe that the double diagonal approach would be far heavier and labor intensive than I am looking for.

    My specifications & objectives;
    1) 18-20 feet long
    2) relatively agile and sporty
    3) shoal draft with a swing keel - in coastal SC this would be to allow traversing the salt marshes without unintentionally using a keel bulb to plow oyster beds... (did I mention I’m new to sailing)
    4) broad beam -8’
    5) Easily manageable sail plan
    6) Cuddy for storage and sleeping in a pinch
    7) Beachable to facilitate camping trips to barrier islands

    I believe that while the bamboo is heavy, it will offer strength as a structural core material that will better adapt to my lack of abilities, and likelihood for grounding, etc.
     
  8. Dolfiman
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    Dolfiman Senior Member

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  9. ExileMoon
    Joined: Oct 2009
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    ExileMoon Junior Member

    I was surprised to see your data. Maybe you haven't actually touched bamboo. In fact, the density of bamboo is about 700~800kg/m3, which is heavier than most woods (correspondingly stronger than wood). If it is fully impregnated with resin, it may sink in water.

    Your data may be intact bamboo (including its internal cavity), rather than the dense material obtained after processing the bamboo.
     
  10. ExileMoon
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    ExileMoon Junior Member

    Bamboo can be split into bamboo strips, which are very flat ribbons with a width of about 10mm and a thickness of 0.5mm, which can then be woven into many items.
    Bamboo strip .jpg Bamboo strip weaving process.jpg

    In ancient China, this material could be used to make the main sails of large ships and the hatch covers of boats.
    bamboo4.jpg
    Of course, it can also be made into the hull of a very small boat.
    First weave bamboo strips into the shape of a boat, and then paint the exterior to prevent water leakage, so that it can be made into a boat. However, in ancient times, there was no strong resin. This kind of hull was usually a single layer, and bamboo strips could not be made too thick, so they were limited to small boats.
    Today, we can still see the remains of this ancient technology in Nha Trang, Vietnam.
    Nha Trang Bamboo Boat.jpg

    If you look at the bamboo mat woven by bamboo strips now, will you find that it is very similar to carbon fiber cloth?
    bamboo.jpg bamboo3.jpg
    Yes, you can get a sufficiently thick hull structure through the layering method just like using carbon fiber cloth for the structure.
     
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  11. Dejay
    Joined: Mar 2018
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    Dejay Senior Newbie

    Hmm interesting. I took it (blindly) from here:

    Density of Various Wood Species https://www.engineeringtoolbox.com/wood-density-d_40.html

    This source says Average Dried Weight: 31 lbs/ft3 (500 kg/m3) to 53 lbs/ft3 (850 kg/m3)

    Bamboo | The Wood Database - Lumber Identification (Monocot) https://www.wood-database.com/bamboo/

    Being heavier and stronger might be a good thing too. I don't think I ever held processed bamboo only intact sticks. Looking at the pictures I wonder if you could vacuum infuse this woven mat like a cloth.
     

  12. ExileMoon
    Joined: Oct 2009
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    ExileMoon Junior Member

    Yes, it is possible to use this soft bamboo mat to make a curved hull like a glass fiber reinforced plastic boat.

    But the original poster meant that he wanted to use a relatively hard plate to make the multi-chine boat.
     
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