Beam design for a demountable catamaran

Discussion in 'Multihulls' started by guzzis3, Dec 21, 2016.

  1. UpOnStands
    Joined: Nov 2015
    Posts: 586
    Likes: 5, Points: 18, Legacy Rep: 16
    Location: Sydney

    UpOnStands Senior Member

    For fallguy, what is the inner hull to hull spacing just prior to dropping in the fore and aft beams? Bigger than 2346mm or 7'9"?
     
  2. fallguy
    Joined: Dec 2016
    Posts: 326
    Likes: 11, Points: 18, Legacy Rep: 10
    Location: usa

    fallguy Senior Member

    8' is the plan. The smaller beam is about 8" in on each side or so, so will be like 9'4", the big beams are just under 15'. Beam of the vessel is about 16', say 15' 9".
     
  3. guzzis3
    Joined: Nov 2009
    Posts: 347
    Likes: 8, Points: 18, Legacy Rep: 42
    Location: Brisbane

    guzzis3 Senior Member

    The hulls may float upright on their own but may not stay that way as you maneuver them around.

    My idea with the dollies is to use a powered or ratcheting caravan mover to get them around on the flat, and an A frame to your tow vehicle to get them down the ramp. It makes them essentially a mini trailer but minimises the depth you need to float them off and means the road trailer does not have to go in the water.

    Anyway I am sure you will figure something out.
     
  4. UpOnStands
    Joined: Nov 2015
    Posts: 586
    Likes: 5, Points: 18, Legacy Rep: 16
    Location: Sydney

    UpOnStands Senior Member

    umm, Richard Woods states that the hulls fit inside a standard 40 container. So, just noodling things. Take a 40 foot high top container and cut a hole in the roof so the cuddy sits partially down into the container but not resting on the hulls. Submerge the container until the hulls float. They are prevented from tipping by parallelogram arms in the fwd and aft beam sockets. The hulls are withdrawn from the container and the arms are extended to spread the hulls
    sufficient to insert the middle beam. The hulls are brought back towards the container, the fwd arm is removed and the hulls are moved fwd to straddle the container and tied off to minimize movement. The middle beam is lowered down the aft face of the container and inserted into the boat. ++ and the hulls are moved together to seat the central beam ++ The boat is moved back and the fwd beam is installed. The boat is reversed and the aft beam is installed. The cuddy is another issue.:eek:
     
    Last edited: Nov 1, 2017
  5. fallguy
    Joined: Dec 2016
    Posts: 326
    Likes: 11, Points: 18, Legacy Rep: 10
    Location: usa

    fallguy Senior Member

    The hulls would need temporary scissors beams so the only maneuvering is in and out.
     
  6. Corley
    Joined: Oct 2009
    Posts: 3,584
    Likes: 86, Points: 48, Legacy Rep: 826
    Location: Melbourne, Australia

    Corley epoxy coated

  7. fallguy
    Joined: Dec 2016
    Posts: 326
    Likes: 11, Points: 18, Legacy Rep: 10
    Location: usa

    fallguy Senior Member

    The easiest thing is to use linear bearings. You get to the landing and run the bunks out wide.
     

  8. fallguy
    Joined: Dec 2016
    Posts: 326
    Likes: 11, Points: 18, Legacy Rep: 10
    Location: usa

    fallguy Senior Member

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.