Any experience with polyethelene hulls?

Discussion in 'Boat Design' started by JonathanCole, Jul 28, 2005.

  1. JonathanCole
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    JonathanCole imagineer

    Polyethelene Hulls are said to be virtually indestructible and maintenance free with a high degree of finish and some even offer a lifetime warranty. Does anyone have any experience with this technology or the comapny that developed it? http://www.genmar.com/page.cfm?id=42
     
  2. yipster
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    yipster designer

    polyetheen or PE you mean? a thermoplast? carver is using it for hulls? make me stand corrected or shoot me to the moon please!
     
  3. JonathanCole
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    JonathanCole imagineer

    Oops, spelled it wrong. Polyethylene. See Rotolene (trademark) hulls in the Genmar web site. Also found some info in the materials forum.

    Morrelli and Melvin, top designers,
    ( http://www.morrellimelvin.com/gj65_photos.html )
    have designed a tri hull pontoon boat for Genmar made from thermoplastic polyethylene and baked in an oven while rotating.
     
    Last edited: Jul 29, 2005
  4. yipster
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    yipster designer

    ok, USCG Certified means something, new techniques used i guess but havent touched that yet.
    thermoplastic's are good for many things but for good hulls their new to me.
    i know small bathtub boats are made from PE but bend, bleach, crack, split without repair.
    but wait, you say polyetylene, i'm no expert and have to dig up my polytechnic books...
    anyone around here with wiser remarks?
     
  5. fx152
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    fx152 New Member

    The new-marine guys have been doing beach catamarans in PE for some time now.
    I think they also use the rotomolding process.
    I've sailed an old rental once and the hulls were still ok.

    Cheers,
     
  6. Sander Rave
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    Sander Rave Senior Member

    It's a perfect material and basicly indestructable. Something for Dinkytoys or rentals...
    You'r limited to the size of your molds. I did lots of products with PE and rotomolding.
    I would use it only for a dinghy, rentals and other stuff that has durability and economics above performance.

    Great material, great opportunities if used in the right way (initial costs are pretty high namely in moulds so you need to have perspective on selling numbers)
    regards,

    Sander
     
  7. kach22i
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    kach22i Architect

    Is it light weight?

    Does it expand a lot or a little due to temperature changes?

    Does it produce less condensation than a metal hull due to it's insulatings features........or is the "due point" in the walls and what havoc does that create?
     
  8. yipster
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    yipster designer

    interesting, but is it still a thermoplast like say a bucket?
     
  9. icetreader
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    icetreader Senior Member

    I use Polyethylene for my boats. It's extremely tough and generally I have only good things to say about it but I wouldn't go as far as saying it's indestructible...

    There's a thread about HDPE (high density PE) in the "materials" forum.

    Yoav
     
  10. CT 249
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    CT 249 Senior Member

    We still sail the original Windsurfer One Designs (the very first windsurfer) as a class down here. They are much flexier and about 20% heavier than "normal" plastic construction and about 50% heavier than carbon. But the durability is incredible. Boats close to 20 years old and heavily used are still fully competitive against the former Olympians at the front of the fleet. Like those PE Optis, they just keep on lasting. PE Toppers in the UK are the second-biggest class.

    IMHO the PE boats, when they get a bit cheaper as moulds expense is ameliorated and second-hand boats become available, will really revive the slower/cheaper end of sailing. You'll be able to waltze into one for not a lot, get some good OD racing and sell it for little loss.
     
  11. Sander Rave
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    Sander Rave Senior Member

    True Icetrader,

    In normal use I mean.
    Expansion is high, like any plastic
    It's a thermoplast like any.
    HDPE is lighter than water, and can be moulded, machined, and joined together using welding (difficult to glue).

    What I also like: It's a good material to recycle
    for additional information folow this link:
    http://www.lgpetro.com/eng/product_info/product/hdpe.html
    grade: MC6001

    you should see this production method like a BBQ: a mould on a grill, filled with some PE and rotated like a turkey or cow
     
  12. gonzo
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    gonzo Senior Member

    There is a company in North Carolina rotomolding powerboats up to 18'. They look Ok. I believe it is the biggest rotomolded object being manufactured. http://www.triumphboats.com/
     
  13. yipster
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    yipster designer

    new chemistry and techniques used i guess, my ( older ) books mention hard PE is not scratch resistant, oils eat it, used for crates and buckets etc. i rowed small double shelled PE dingy's, seen torn ups and still got to be convinced...
    http://en.wikipedia.org/wiki/Polyethylene
     
  14. icetreader
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    icetreader Senior Member

    PE can be scratched, but what material is totally scratch resistant?...
    My experience with PE is that it resists oil-based solvents very well.

    It's only natural that good materials find uses in a wide variety of applications -after all steel is used in products ranging from sewing needles to submarines [​IMG]

    Yoav
     

  15. yipster
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    yipster designer

    guess i / we are lost in the wonderfull world of chemics. just checked UHMWPE that got me impressed allright.
    HDPE resists many chemicals, not oil and fat based solvents very well.
     
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