Lightest hard center deck for a small cat

Discussion in 'Multihulls' started by rayaldridge, Feb 8, 2011.

  1. rayaldridge
    Joined: Jun 2006
    Posts: 581
    Likes: 26, Points: 0, Legacy Rep: 322
    Location: USA

    rayaldridge Senior Member

    oldsailor, was it possible to fold the boat with the rig up? Did you have some way to fold and unfold the boat while aboard?
     
  2. Steve W
    Joined: Jul 2004
    Posts: 1,824
    Likes: 63, Points: 48, Legacy Rep: 608
    Location: Duluth, Minnesota

    Steve W Senior Member

    Ray, i think, (but im not 100% sure) that the beams on some cats that have the beam slide in a tube glassed into the hull have the beams quite a bit smaller than the sleeve and then have nylon buttons making up the difference so they wont sieze up and be difficult to slide.
    Steve.
     
  3. rayaldridge
    Joined: Jun 2006
    Posts: 581
    Likes: 26, Points: 0, Legacy Rep: 322
    Location: USA

    rayaldridge Senior Member

    Steve, that makes sense. I'll bet some of that HDPE stuff would be even better.

    At one point, I had a system designed that used beams sliding past each other within a captive box. There was substantial space around the beams, but they tightened into rigidity when at the end of their travel, they engaged wedge-like structures. They could be cranked open and folded using simple tackles, so that it could be done afloat.

    The issue with this system that led to me abandoning it was the rig. I wanted to be able to leave the rig up when the boat was folded, because of my personal situation. The slip that is available for my use (from a generous neighbor) is only 10 feet wide, so in order to keep a boat with 12 foot beam in the slip and be able to use it conveniently, the rig had to remain up when the boat was folded.

    The great advantage to a system that folds at armpits and central spine is that as the spine moves forward and the hulls come together, the geometry can be arranged in a way that keeps enough tension on the shrouds to support a rotating mast adequately. The forestay can be attached to the forward extension of the spine, which when sailing, can be adequately stabilized by a bridle. This bridle will fall slack when the boat is folded, but the central spine will carry the forestay in the same position relative to the mast.
     
  4. oldsailor7
    Joined: May 2008
    Posts: 2,097
    Likes: 40, Points: 48, Legacy Rep: 436
    Location: Sydney Australia

    oldsailor7 Senior Member

    Since I only folded the boat to trailer it, I lowered the mast first, then folded the hulls in the water and pulled it out onto the trailer.
     
  5. horacewimm
    Joined: Feb 2011
    Posts: 7
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: UK

    horacewimm Junior Member

    Okay I dont know if amyone else has mentioned this before now. But we use Nidaplast. Its not a foam but rather a cellular design which must be laminated on both sides before use. Foam isn't really structural whereas Nidaplast is. Plus it comes in various types and thicknesses which is very handy. Once done its very light and damn near indestructable..
     
  6. Eagleburger
    Joined: Mar 2011
    Posts: 6
    Likes: 1, Points: 0, Legacy Rep: 10
    Location: brisbane

    Eagleburger Junior Member

    Sounds like some stuff that my mate showed me a while age. He uses it to make flybridge floors. Incidentally I am going to use it for a deck on a small cat myself.
     
  7. horacewimm
    Joined: Feb 2011
    Posts: 7
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: UK

    horacewimm Junior Member

    We use it on every boat we make now. Its great stuff. Of course there caveats. But on the whole its a great product. I reckon its added about 40% extra strength with a weight saving of about 68% to our catamaran decks and stringers. There are a few do's and dont's though. Forinstance its good practice not to lay it directly against the hull, when using for bulkheads. We use a little foam as an isolater between the hull and the Nida. This was a tip given to us by a builder who had been using it for a while. The reason is. Its so strong in compaction that you can get cracks in the gel apperently if you dont use this method. I will try and upload some pics to show this...
     
  8. Steve W
    Joined: Jul 2004
    Posts: 1,824
    Likes: 63, Points: 48, Legacy Rep: 608
    Location: Duluth, Minnesota

    Steve W Senior Member

    Horace, that method of installing bulkheads has been pretty much standard practice,even with plywood bulkheads for the last 30 -40 years,particularly with solid glass hulls,although many do not do it.
    Steve.
     

  9. horacewimm
    Joined: Feb 2011
    Posts: 7
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: UK

    horacewimm Junior Member

    dont get me wrong, you are correct. Just pointing out that it really is a must with Nida. I have seen makers not doing it though and I was a little shocked.
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.