Needing Deck and Cabin Materials / Structural help...

Discussion in 'Materials' started by jedclampit, Feb 4, 2006.

  1. jedclampit
    Joined: Jan 2006
    Posts: 69
    Likes: 1, Points: 0, Legacy Rep: 12
    Location: Hollywood, Florida

    jedclampit Junior Asparagus

    Here we go again… How do I top off a 7,000 pound wood hull?

    I have a (full displacement) 40’ Bruce Roberts Spray hull made of a solid yellow pine keel and 1-1/2”x1-1/2” steam bent mahogany strip plank and epoxy monolithic hull (the 3x12 yellow pine mold or skeleton is still in its belly). The original owner was in the process of starting the deck runners and such.

    I want to build the decks, cabin and a pilot house out of lightweight fiberglass or something strong and light (cf is not an option). I need to keep her finished weight below 18,000 pounds for my custom trailer. I would like to reinforce the keel to accept external ballast that could be moved separately from the ship. She is 40’ long, 14’ beam, and 12’ from keel to base of the removable pilot house connection point. My thoughts were to be able to move her across country later in her life…to do the pacific coast, etc. I’m having a trailer built for the purpose of moving her to her new home for completion, so I figured that the idea of having a removable ballast or adjustable ballast would be a good thing, since the trailer limitations and all. This would also free up areas for fuel, water and holding tanks in her bilge.

    My question is this: How do I build a lightweight structure and incorporate all the structural elements within the element (monolithic in nature). I need to keep the cg down and I’m building upwards in height, therefore I’d like to incorporate the beams and structural elements within the fiberglass. I will be building the deck and cabin in place using the existing skeleton to form the male mold. I was thinking of making a sandwich and enclosing all structural elements. But I wanted to be able to connect the glass from topside to the bottom side periodically in the construction to add strength.

    1) Is this the best solution?
    2) What is the best way to do this?
    3) How do you feel about the external ballast?
    4) This is a large area to be worked. Is there a way to glass small workable areas at a time and still get a monolithic result? I’m afraid to do too large of a project by myself at one setting. Anyone have an idea how to do this in glass?

    I like the look of the mahogany hull but I don’t like the maintenance of any wood on a boat. In fact I know that most of you will probably hate me for saying this, but the first thing that I have done on my existing and previous boats was to rip the teak trim from their cold fiberglass hands.

    I am planning on finishing the exterior of the mahogany hull by clear coating to protect the hull and preserve the nautical feel of her lines, but from the top of the toe-rail inward will be a clean ultra modern and a bit futuristic design. Even the interior will be 100 percent marine ply epoxy painted to give clean contemporary lines. Not a piece of natural wood will be found topside or down below. Stainless and aluminum will be the choice of trim and rigging. I don’t want her to even look like a wooden boat while you are on board.

    With this said, I’ve not decided what to do with the interior cabin ceiling, but that’s not important what is important is to determine how to complete the build to insure that she is able to cross the Atlantic one day, while keeping her topside as light as possible.

    Any ideas on how I can achieve this goal?

    Thanks again for all your ideas.

    (civil engineer and first time boat builder)
  2. mariner 40
    Joined: Nov 2005
    Posts: 59
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    Location: Salem, Indiana

    mariner 40 Junior Member

    A friend of mine built a 28' h28 and strip planked the deck and cabin. The most beautiful boat I have ever seen! I have a 40' that I am replacing the deck. I'm going with plywood and fiberglass. Since you don't like wood, buy some of those welding rods to bond wood to steel and weld a metal deck to it! As for trailoring, take it through the canel, sould be a trip of a lifetime!
  3. jedclampit
    Joined: Jan 2006
    Posts: 69
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    Location: Hollywood, Florida

    jedclampit Junior Asparagus

    Real Help Needed Here! Please!

    I’m sorry but didn’t want to get into a discussion about having a “wood” boat or going through the canal. I love wooden boats as long as they are someone else’s. And I love the idea of going through the canal, but that’s not for me. I know that many live aboard sailors are a bit eccentric or even crazy, so please leave me to my own quarks. I’m going to use marine plywood throughout my cabin for all of my woodworking (below the cg as much as possible), so I have nothing against wood, I just don’t want to maintain the look of natural finished wood when I’d rather be out on the water. I like the clean look and feel of fiberglass and would feel much better about using or abusing my boat instead of pampering the wood finish or having to watch out where you throw things… and knowing that all I should have to do is to mop and rinse should keep the deck and superstructure looking good.

    My intent was to find help on a rigid sturdy fiberglass “hull like” procedure for building my deck and superstructure. I’ve seen many fiberglass hulls where the structural members and the foam core are installed or embedded into the fiberglass (sandwiched) as it was being laid. This works great on a female mold, but how can I do this on a male mold?

    I want both surfaces to be connected or bonded as in the case of a hull. I don’t want there to be a continuous core without the two surfaces bonded together. Has anyone built a male mold structure incorporating this concept? I need to build light and super strong like a fiberglass hull. I would like her to be able to withstand a 180 degree capsizing and right herself without damage.

    And what about the problem of patchwork? Is there a way to build a large surface without having to glass the whole thing in one setting? My deck and structure will be about 600 square feet of surface area. I’m new to glassing and boat building so I need an expert’s advice here.


  4. JR-Shine
    Joined: May 2004
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    Location: Vero Beach, FL

    JR-Shine SHINE

    You should use a core with glass on each side. That core can be foam, honey comb, or even plywood. I would use plywood with glass/epoxy.
  5. jedclampit
    Joined: Jan 2006
    Posts: 69
    Likes: 1, Points: 0, Legacy Rep: 12
    Location: Hollywood, Florida

    jedclampit Junior Asparagus

    Thanks Shine...

    Thank you. I think that I will use that method. I was concerned with connecting the outer layers with the inter layers. Is this needed?

    I was thinking of using the tape and seam method with an additional layer of glass or two on the inside.

    Do you have any recommendations of what glass and how many layers?
    I was going to use 2 layers of 3/8" ply on the decks and cabin top and 1" ply for cabin sides. (all over structural members). And I will rap the members in glass as well.

    What would be the finished weight of the glass on both sides (per/sq.ft.)? Any clue? I need to calculate my final weights. I’m new to glass…and boat building.

    Thanks again.


  6. SeaJay
    Joined: Jun 2007
    Posts: 211
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    Location: Sacramento

    SeaJay Senior Member


    It has been some time since this thread began, do you have an update? I am interested in what you decided upon.

    Best Regards,

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