Re-cutting beach cat sail to go boomless

Discussion in 'Multihulls' started by Jetboy, Mar 31, 2015.

  1. Jetboy
    Joined: Feb 2012
    Posts: 278
    Likes: 6, Points: 0, Legacy Rep: 65
    Location: USA

    Jetboy Senior Member

    Has anyone done this? I'm slowly nearing the date when my home built trimaran will be ready for sea trials. I'd very much like to set it up boomless as I've been pretty pleased with the simplicity and easy of sailing on boats like the Hobie Getaway.

    I'm NOT looking for the last 1% of performance, or really saving $ - I have a boom setup for this application, but I'd rather not use it. Just a very comfortable, fast, daysailer. So I've been looking at some Nacra 5.2 sails or similar fully battened high roach main sails from similar size catamarans. I'd like to start with some cheap used sail at first and buy a custom set possibly this fall after I get a little better feel for what I want in a set of sails. The used set will be smaller than what I'll get in the final version custom made and useful for higher wind days or lazy cruising.

    The boat will have a main, jib, and some type of big down wind sail - code 0 or similar on a roller up front.

    So... is it possible to cut a main sail foot and add an appropriate clew to go boomless? What are the keys to a proper cut? Could a regular loose footed sail simply be used with addition of a lower batten and the main sheet track far enough aft?


  2. gonzo
    Joined: Aug 2002
    Posts: 16,796
    Likes: 1,718, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    The cut is very different. If you want to try boomless, just use it as it is. It won't break, but the set will not be ideal.
  3. catsketcher
    Joined: Mar 2006
    Posts: 1,315
    Likes: 165, Points: 63, Legacy Rep: 790
    Location: Australia

    catsketcher Senior Member

    Ian Farrier has boomless as an option for the F22. Have a look at his page and read about the issues with it. His track is aft of the clew.


  4. warwick
    Joined: Jan 2012
    Posts: 423
    Likes: 7, Points: 18, Legacy Rep: 63
    Location: papakura south auckland new zealand

    warwick Senior Member

    That is a battern along the foot, they also furl the main around it.
  5. Jetboy
    Joined: Feb 2012
    Posts: 278
    Likes: 6, Points: 0, Legacy Rep: 65
    Location: USA

    Jetboy Senior Member

    Its a trade for ease and convenience. Especially for a trailer sailor. With a fully battened and loose footed main the outhaul doesn't really do much in most cases. It seems to me that an aft sheet should work well on most points of sail up to beam reach. Downwind i had figured a code 0 should do most of the work. I suppose running in high wind would be the worst without a proper boom.
  6. Munter
    Joined: Jul 2007
    Posts: 285
    Likes: 12, Points: 18, Legacy Rep: 125
    Location: Australia

    Munter Amateur

    It won't be so much about the cut of the sail as any changes required to the sheeting angle. Without the boom to hold the clew back you will probably need to move the traveller aft in order to apply sufficient rearwards force to flatten the foot, otherwise you may end up with excessive foot camber.
    Perhaps one way of solving the potential issue would be to rebuild the clew reinforcement to include a clew plate with multiple attachment points which would effectively allow you to move the attachment point forward and therefore apply more rearwards force to the clew.
  7. Petros
    Joined: Oct 2007
    Posts: 2,934
    Likes: 148, Points: 63, Legacy Rep: 1593
    Location: Arlington, WA-USA

    Petros Senior Member

    Recut the foot of the sail and use it as a loose footed main, you will only need a very simple pole for a boom, it can even be lashed to the mast with a snoter. Minimal hardware and loads on the boom are small, so it can be light. the sail you have would be much easier to adapt to a loose footed main rather than a boomless rig.

    I have used it on many simple dingy rigs and love it for its simplify and low cost, yet still gives you most of the advantages of a conventional boom as far as adjusting sail shape, position, twist and other trim options on the mail. None of that would be true with a boomless rig, which I have also built, simple to control but find it not as adaptable to all wind conditions.

  8. teamvmg
    Joined: May 2008
    Posts: 124
    Likes: 4, Points: 0, Legacy Rep: 22
    Location: christchurch,uk

    teamvmg Senior Member

    The cut of a loose footed sail will be fine
    All boomless sails are very sensitive to the sheeting angle of the mainsheet.
    Very tricky to get the main traveller position right so fit a long clewboard with multiple holes to give adjustment
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.