Designing a 43' flat panel performance cruising catamaran

Discussion in 'Multihulls' started by sailhawaii, Jun 7, 2019.

  1. sailhawaii
    Joined: May 2016
    Posts: 12
    Likes: 1, Points: 3, Legacy Rep: 10
    Location: Indian Harbour Beach, FL

    sailhawaii Junior Member

    I'm working on a 43' CNC cut flat panel catamaran design. I just finished a 1:20 scale RC version of it.
    My current thinking it to open source or more correctly creative commons the plans.


    If I can get it refined to the level I like I plan to build a full size version. I shared a early drawing here a couple of years ago and nobody seemed to care for it. It's inspired by the Schioning Arrow series and the Grainger Raku series. Both of which I think are awesome boats.

    This is the build video showing the final RC version sailing:


    It's just a hobby for me, so if anyone wants to help contribute to the design of the project I would be happy to share it.
     
  2. oldmulti
    Joined: May 2019
    Posts: 73
    Likes: 49, Points: 18
    Location: australia

    oldmulti Junior Member

    Hi. The model looks good and I like the concept of a flat panel construction method. I have seen 5 flat panel cats being made from 35 to 48 feet. They all eventually worked well but the panel layout and fitting really depended on a good basic design. Some flat panels get very stiff and difficult to twist into shape if to much glass is applied prior to placement. Also like all chine boats getting the chine or step lines to be visually acceptable can require a lot of fairing after the panels are taped together. The Harryproa site has an interesting way of producing cheap mold for EG hull bottoms that then may be able to be joined to a flat panel rest of the boat. PS over on the Multihull Structure Thoughts thread i will in the next few days do a post about cross beam structures for 40 odd feet cruiser racer cats.
     
  3. sailhawaii
    Joined: May 2016
    Posts: 12
    Likes: 1, Points: 3, Legacy Rep: 10
    Location: Indian Harbour Beach, FL

    sailhawaii Junior Member

    Thanks. The first models I build had some curves that were difficult to make with panel flex, but I changed the design so it's not a problem anymore (the problem areas seems to be the front of the bridge deck and the bow esp the inside) . I have seen the fairing problem you are talking about already on my models. The more accurate I get the panels including my notching system helps a little to improve that, but it's still an issue. I'm actually thinking about routing the core before any fiberglass is on it. Then I can route small tracks similar to drywall seams for an extra layer of glass tape at the seams. I may even attempt to route the foam at an angle to make a perfect fit. I have seen many full size kit airplanes that they are able to CNC the parts so that you don't have to even drill holes everything just lines up and you rivet it together. I'll see what my continued experimenting turns up to work.

    I've looked at the Harryproa site before I'll take a look again and keep an eye on the other thread.
     
  4. oldmulti
    Joined: May 2019
    Posts: 73
    Likes: 49, Points: 18
    Location: australia

    oldmulti Junior Member

    Hi, look at the Multihull Structure Thoughts thread page 3 and 4 for some cross beam ideas that may help your design process.
     

  5. magwas
    Joined: Oct 2009
    Posts: 280
    Likes: 7, Points: 18, Legacy Rep: 47
    Location: Hungary

    magwas Senior Member

    What is your approach to size the aka to be structurally sound? I think that any plan should be backed by calculations or scantling rules. I guess I know how to size the amas based on a scantling rulebook, but the only ways I know for sizing the aka is either as classical beams (which is hard because the geometry), or finite element analysis (which I am too dumb to do).
     
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