Houseboat weight

Discussion in 'Boatbuilding' started by boulty123, Mar 2, 2013.

  1. tomas
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    tomas Senior Member

    Yes, in the 3.5m HDPE jetboat thread, the builder reports: "the plastic got to about 70 deg c the other day in the sun and grows about 10mm/1m".

    As you point out, any design where this expansion can cause stress problems, will have to accommodate this somehow.


    I'm wondering about the scenario in which a larger boat with a full HDPE deck, is out on the water under a hot sun. It would seem that deck expansion would start to rip away from it's anchoring to the hull structure, as CDK described above.

    Thanks for sharing your experience.

    It's definitely easy to weld and robust, as shown here:

     
  2. tomas
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    tomas Senior Member

  3. Scottym
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    Scottym Junior Member

    The extrusion welder I used was a Leister ....S model I believe. I hired it as at the time purchase of a new one was outside my cashflow and I couldn't find a second hand unit. They are around $6000 new . If I did another I would buy and then sell on afterwards , as it would be less than the hire cost. That way I could take my time more as well without seeing $ signs tick over by the day.
     
  4. Scottym
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    Scottym Junior Member

    Hi, My experiance wasn't the same for expansion however my HDPE was much thicker and also as a pipe so I get was resisting the expansion within itself. I would not think that HDPE would be very good as a large flat surface . I think it would ripple and buckle as it heated and cooled. Cored hdpe may be better in this regard - black color would certainly be the worst.
    As a pontoon hull I think it is idea ( it negates all the traditional drawbacks of other hull materials in a houseboat situation) but for exposed superstructure probably not ,and would have no significant benefits to offset the weight of the material.
    There are several manufacturers making larger rotomoulded HDPE boats successfully and also specialist fishing and rescue boats out of hdpe sheet and pipe ( see the Aquatruck) but not on the scale of a launch or houseboat.
     
  5. tomas
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    tomas Senior Member

    Cored HDPE? I'll have to look that up.

    I think your summary is spot on: it's excellent candidate construction material for buoyancy components when shielded from solar heating.

    BTW Scotty and CDK, the Aquatruck is 20 feet long, black and is NOT roto-molded. According to the product brochure it is an HDPE extrusion welded hull, fully framed and ribbed, with a minimum 10mm thickness, and pontoons that are minimum 13mm thickness.

    It has quite a bit of surface area exposed to the sun so how does it not warp and distort?
     

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  6. Scottym
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    Scottym Junior Member

    I think pipe doesn't distort as much because of the inbuilt contaction stress. To explain.... I found that when I cut a longtitudanal slot in the large diameter pipe , the pipe slowly squeezed the gap in a little. A ring cut off the end and then cut through also contracted so the ends passed each other. As a rough guide a 1000mm pipe wanted to relax to about 950mm diam. To my mind this means the pipe is in a "stretched" form when made. Therefore when heated all it does is relax some of that " stretch" by expansion.Its just a guess but it does explain why less expansion is noticible. As for some flat areas not expanding - this may be because the material is elastic to a certain extent.When unrestrained it will expand but when fixed or welded into a structure it can absorb a fair bit of those expanding forces by compressing.
     
  7. srimes
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    srimes Senior Member

    HDPE pipe does distort, and quite a bit. It is well known for this.

    I bet the aquatruck does change shape. But it's the same material and quite flexible so it just "moves" together, and returns to the original dimensions when it cools off.
     

  8. FLOATINGvillage
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    FLOATINGvillage New Member

    Floating Touristic Ecovillage Project :))

    ROTOMOULDED HULLS FOR AFFORDABLE FLOATING ECOVILLAGE ???


    Dear Sir,

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    Mr John Venier, the coordinator of the WAVE International initiative ; Wetlands, Coastal and Marine Resources Management through Mainstreaming EcoAgrotourism based on local community empowerment, asked me to contact you to introduce our sustainable-tourist mainstreaming model initiative, targeted to empower women, youth and fishermen and farmers in the wetlands and coastal regions of emerging countries around the globe.

    The aim and intention of our initiative is to create an actual operational model which will give life force, or which will empower international and national support programmes such as the Global Environmental Fund, UNPD, UNEP, etc.... ( The GEF and/or OTHERS NGO grants funders for marine and coastal management programs.) Our initiative, WAVE International, is unique in the world in that it uses breakthough innovation and available resources such as GSTC, STEP, SIFT, to enable wetland communities to create and invest in their own local economies by creating floating eco-villages and eco-resorts.



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    As the English (and German) speaking correspondent for WAVE initiative, I would be grateful to be able to speak with you on the phone about our project and possibly find ways in which we could collaborate.

    Mr Venier would like to invite you to attend our "FUTUR EN SEINE" event on June 19th and 20th, 2013 in Paris. He would also like to invite you for a private meeting, on any day between June 24th and 28th of june, or whenever it would be convenient for you.



    Please contact Mr Venier at the above email address for more informations or help :

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