Sheathing for over-the-waterline houseboat hull

Discussion in 'Boat Design' started by Marten, Mar 9, 2011.

  1. Marten
    Joined: Oct 2010
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    Location: Sweden

    Marten New Member


    I'm building a houseboat based on a platform of merged/connected glulam balks. The platform measures 9x8m (~26x30') and will use three 10.5x1x1m (~34x3x3') aluminium pontoons for floatation. It has a quite strong wooden skeleton to provide structural strength and it's sheathed with 12mm plywood.

    I don't have any experience with fiberglass/composites and I've had much trouble finding the adequate information regarding the optimal sheathing for my application.

    I would say that the skeleton and plywood skin provides all the required structural strength (even though it will flex a bit), so I just need a coating that acts like a water/weather protectant. I've decided to use epoxy resin, but when it comes to fiberglass, I have no clue. Which material and weight would you use?

    Please see attached image for an illustration of my hull design (the pontoon-like formations are just adapters where the aluminum pontoons will be mounted, and the hull is upside down).


    Attached Files:

  2. rasorinc
    Joined: Nov 2007
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    Location: OREGON

    rasorinc Senior Member

    If you are just looking for water protection 7 oz. fiberglass is more then adaquite. Remember even the best epoxy needs UV protection such as paint or varnish. One summer in the sun will really damage epoxy.
  3. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Log onto and and download their user guides. It will explain the products and techniques common to all uses and resins systems.

    The inside corners will need to be radiused so the fabric will lay down neatly. A simple fillet will do. Outside corners will also need radiusing. A light weight cloth, as Stan has mentioned will do, say 200 g/m (about 6 ounces), though a heavier fabric maybe a 340 g/l (about 10 ounces) will offer more abrasion protection. Naturally, a heavier fabric will also require more resin to wet out and fill.

    Don't skimp on paint. This is your surface protection (again as Stan has noted), so at least 3 coats of primer, more if you sand them smooth and 3 coats of topcoat, more if this is sanded smooth.

  4. Marten
    Joined: Oct 2010
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    Location: Sweden

    Marten New Member

    Okay, thank you guys. Appreciate it!
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