Power trimaran world cruiser

Discussion in 'Multihulls' started by teamcallander, May 13, 2017.

  1. teamcallander
    Joined: May 2012
    Posts: 16
    Likes: 2, Points: 3, Legacy Rep: 15
    Location: Belize

    teamcallander Junior Member

    30 meter with sky.jpg 30 meter flying bridge.jpg 30 m main deck.jpg 30 meter lower deck.jpg

    Hi there

    A few years back I posted some design ideas for an 80 ft power trimaran on the forums here and received a lot of very good feedback from the members which I really appreciated. It helped me to refine what was important and to get read of a bunch of stuff that wasn't. As a result I went back to the drawing board and also talked to some industry folk about what customers want and need in a boat designed to be a world cruiser.

    My background is in hydrogen fuel cell and renewable energy system design but in order to really make the most of those in a boat you really need to start with something different from what the mass production market currently provides. This is my first attempt at transferring my design ideas into a CAD program - I used Rhino and Flamingo - and I'm pretty happy with the result but in reality everything can be improved on.

    But enough of the preamble, here are the specs:

    - 10:1 round bilge, canoe bottom power trimaran of 98ft length and 30ft overall beam
    - max draft 4ft
    - 35 tons light ship
    - 2000 gallons of fuel
    - accommodation for 10 in 5 ensuite guest cabins
    - separate entrance crew quarters with accommodation for 4 in 2 cabins plus kitchen and bathroom
    - 17ft dinghy garage with rear door onto swim platform
    - all the usual amenities on the main deck and flying bridge

    Anyway, I have a attached a short (six page) overview of the design with some renders if you want to know more about it.

    Thanks and very much looking forward to your feedback!
     

    Attached Files:

    Doug Lord likes this.
  2. teamcallander
    Joined: May 2012
    Posts: 16
    Likes: 2, Points: 3, Legacy Rep: 15
    Location: Belize

    teamcallander Junior Member

    Forgot to attach the side view...

    30 meter side view.jpg
     
  3. teamcallander
    Joined: May 2012
    Posts: 16
    Likes: 2, Points: 3, Legacy Rep: 15
    Location: Belize

    teamcallander Junior Member

    Ok, so I don't think I was specific enough in my first post. The following points are what I am most interested in hearing about in the context of this design:

    - thoughts on twin Yanmars Vs single Cat 12 ACERT for propulsion
    - thoughts on fiberglass Vs aluminum construction for a vessel of this size
    - would you prefer it to be bigger, smaller or is it just about right?
    - exterior styling thumbs up or thumbs down?

    Cheers
     
  4. ChrisPie
    Joined: Aug 2017
    Posts: 1
    Likes: 0, Points: 1
    Location: Australiawhar

    ChrisPie New Member

    Hi.
    Have you settles on the placement of the amas? You can design them to be riding on the bow waves of the main hull creating lift and reducing drag. This only applies at one particular speed. Compared to other designs I have seen your design looks a little narrow to achieve this. I would love to understand how this is calculated?
     
  5. teamcallander
    Joined: May 2012
    Posts: 16
    Likes: 2, Points: 3, Legacy Rep: 15
    Location: Belize

    teamcallander Junior Member

    Well if you look through the scientific literature on the effect of ama placement on overall powering requirements you find that at speeds below 28 knots moving them forward or backward makes little difference (less than 10%). The main thing to worry about is wave interference between the hulls and for that the further you can space the hulls the better.

    For a practical design below 28 knots I decided to give precedence to interior layout and it just works much better having the ama's amidships when it comes time to laying out the interior on the lower deck. Hence my central placement with a 3:1 overall beam to length ratio. If you look at other designers Nigel Irens runs about 3:1 (mid placement) on his designs and Craig Loomes uses 2.2:1 (rear placement) so there is a range.

    As to your question about getting the ama's to surf on the bow wave I'm not sure how you would calculate that other than by 3D printing a scale model of your design and just doing some tow testing in the local swimming pool. That way you can play around with ama placement to your hearts content and see the impact at different speeds.

    What do you want to use your boat for? If you are looking at a long distance ferry application then optimizing around a specific speed might be commercially viable. If it is for recreational use then optimizing across the full range of operational speeds makes more sense because that is how recreational boaters tend to use their boats.

    Wave interaction between hulls is a major efficiency problem when its done wrong and my advice would be to minimize those interactions entirely rather than trying to optimize them at one specific speed range.

    Hope that helps?
     

  6. AquaDive
    Joined: Jun 2018
    Posts: 1
    Likes: 0, Points: 1
    Location: Hong Kong

    AquaDive New Member

    Hi Teamcallander, I like you concept, low fuel etc (el. motor / fuel-cell)..if you don't mind could you contact me on info@aqua-dive.net
     
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