FAO 7.8 meter trimaran ocean capable?

Discussion in 'Multihulls' started by Steel Hull, Sep 30, 2023.

  1. Steel Hull
    Joined: Apr 2022
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    Steel Hull Junior Member


    please general opinion on this design;

    FAO Fisheries & Aquaculture https://www.fao.org/fishery/en/vesseldesign/sol-2a

    Could a FAO 7.8 meter trimaran, properly build, decked over, with a minimalist cabin and low aspect junk rig, do the same kind of offshore and ocean voyaging as a Wharram Tiki 26? Drogue or sea anchor can be used when conditions get too bad. Built in buoancy. Solo sailing most or with max. 2 persons. Emphasis on safety not speed.

    Or is it a complete bad idea?

    I know I am comparing a tri vs a catamaran. But I like the looks of the design, relatively easy and economic to build, the fact that I can build her in my shed and she can easily be trailed and stored. Can be shipped in a 30ft container. Low hp outboard engine.

    Thank you in advance for the input!
  2. oldmulti
    Joined: May 2019
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    Location: australia

    oldmulti Senior Member

    Steel Hull. The FAO 7.8 mtr tri was designed for near shore fishing and transport etc. Yes it could cross an ocean if sailed by some very good sea people but there are several issues to deal with. The floats are small, modern ocean going tri's have larger floats. Larger floats provide more stability to minimize the chance of capsize. The problem with multihulls is you can be capsized by large waves as much as you can be capsized by wind forces. If you put larger floats on this design you will need stronger cross arms (beams) to deal with the extra stability. This leads to the second problem the weight of this tri in its basic form is 1770 lbs. This is a light weight for a 26 foot trimaran. After you modify it to add a cabin and make it ocean crossing capable you will add 100's of extra pounds of weight and if you have larger floats and crossbeams you will add more weight. This is not good and can compromise a reasonable design.

    An alternative may be EG a Scarab 8 mtr tri that can be built in plywood and is designed to be an ocean crosser. Very good plans available at $150 Australian at: Plans for the Scarab 8 folding trimaran http://www.teamscarab.com.au/Scarab8Des.html

    Start from a design intended to be a good safe cruiser that will have a resale value. The one thing I have learnt over my time is if you start cheap and modify you will end up with a boat that requires constant maintenance and never really achieves what you want. If you like EG a Tiki 26 then build one. Plans are a very cheap part of an overall build and in the end save you money and time as you will not be guessing about what is needed to be made stronger or EG how much material is needed to buy etc.

    Hope you find what you want.
    bajansailor likes this.
  3. Steel Hull
    Joined: Apr 2022
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    Steel Hull Junior Member


    thank you for the clearly explained answer.

    I appreciate it and draw my conclusions from it and will look forward to other designs and the Scarab you suggested. (in fact, I already have the plans for the Scarab 650 but that dates from years ago with a different mindset)

    Thanks again!
  4. kapnD
    Joined: Jan 2003
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    kapnD Senior Member

    The FAO7.8 looks like a quite capable hull for minimalist cruising, as long as weights are not excessive. This boat is specifically designed to carry a big load of fish safely, so adding a bit of weight is not going to sink it!
  5. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    Converting that boat to steel is going to make it heavier. Why don't you stick to the original design?
  6. Steel Hull
    Joined: Apr 2022
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    Location: Belgium

    Steel Hull Junior Member

    KapnD thanky you for your opinion

    Dear Gonzo,

    you accidentally mixed it this conversation up with another thread.

    This is about the capability of the FAO 7.8 meter tri...

    Thank you for the reply anyway
  7. Cheevo
    Joined: Jan 2023
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    Location: Papua New Guinea

    Cheevo New Member

  8. waterbear
    Joined: Mar 2016
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    waterbear Senior Member

    I say yes, you can take that design offshore. Whether it's a good idea really boils down to your own tolerance for risk/discomfort. People have crossed oceans in Hobie cats, dinghies, paddle boards, west wight potters, etc, so I don't see why that trimaran can't do the same.

    That said, there are probably better boats out there for your time/material costs. As for the Tiki 26, I think the perception of seaworthiness has as much to do with Wharram's marketing than anything else. Good boats, but there are more modern easy-to-build designs that I suspect are just as seaworthy, if not more so.
    Last edited: Oct 7, 2023
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