Figuring the Cat's boom size

Discussion in 'Multihulls' started by YoungGrumpy, Nov 16, 2012.

  1. YoungGrumpy
    Joined: May 2012
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    YoungGrumpy Junior Member

    As many of you already know,
    I am working on old Seawind 24 cat. Yesterday I got to the boom that came from PO, to see its condition and what needs to be changed/fixed. Well, 2 things obvious, it was bend sideways, and it is most likely not an original for the boat.
    So I am thinking about finding a new one. The boom I've got is 134.5 inches long (gooseneck and end fittings extra).
    Then, if I meassure the distance between the 2 beams (one the mast stays on, and the aft one with the main traveler track), I've got around 127 inches. Assuming the mast is vertical and the boom is horizontal, should not it be almost the same? Or, how much bigger could the boom be? I would not want it to stick outside of the aft end of the hull, and the mainsheet pull probably is better directly down from the boom end?
    As I am on a budget, I will be looking for a used one, any advise on what too look for, and what to be aware of is appreciated.
     
  2. waikikin
    Joined: Jan 2006
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    waikikin Senior Member

    The boom usually is some amount off horizontal like here.... http://www.google.com.au/imgres?hl=...w=136&start=0&ndsp=21&ved=1t:429,r:4,s:0,i:81

    I usually set the boom much higher than the usual gooseneck to a peice of track attached to the mast above head height so I can put an awning over it, but I use my seawind more like a pontoon boat than a sailing machine:D
     
  3. YoungGrumpy
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    YoungGrumpy Junior Member

    Yep,
    it looks like my mast has this track option.
    Still,
    is it overly dumb question or just very boring one? The difference I've got is more that the angle should account for.
    So, how much should the boom end stick outside of the traveler when the boom is directly in the middle?
     
  4. waikikin
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    waikikin Senior Member

    From memory it is a bit that it hangs out with the boom centered, your not close hauled all the time, when the traveler is eased the geometry changes - seawinds have a strait traveller, if the traveler was curved the geometry stays similar. Measure your mainsail foot & the boom can be a foot longer & be fine, there may be some pics on the web to illustrate. One of the simple systems that can be fitted to your boom as the clew attachment also incorperates the attachment of the mainsheet & is simply some webbing & 3 D rings, multiple layers of webbing can be used if required, 2 D rings shackle together to attach the main sheet & the 3rd(running or stitched in) attaches the clew, the main outhaul is attached to either the top D ring or the clew. puts everything in the load path as required & dont relie on bolts & rivets so much, it might be a bit tougher to adjust foot/clew position while underway due to friction on the boom but I've used this system with no probs. Jeff.
     
  5. YoungGrumpy
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    YoungGrumpy Junior Member

    Jeff,
    Since I've got no sails, I was thinking to start sizing from the boom, then order a new sail right size.
     
  6. waikikin
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    waikikin Senior Member

  7. YoungGrumpy
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    YoungGrumpy Junior Member

    thanks,
    I've filled the quote request form.
    Will try to give him a call during the working hours next week.
     
  8. bruceb
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    bruceb Senior Member

    backwards?

    Grumpy, I would not buy a new main for your boat, there are much better places to spend your money. If you go on line under used sails, Bacon, Atlantic and several other companies carry a good selection of sails that will "almost" fit your boat. I would find a main with almost the right hoist, and it will probably be close on the boom, but if not- you can then size the boom to the sail foot. It sounds as if your boom is about the correct length anyway, but as long as it clears the backstay (if you have one), you can make it work. Tris are very forgiving on sail balance and size. The boom does need to extend past the traveler by at least a few inches when centered, but the sail's foot can be a bit short. B
     
  9. YoungGrumpy
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    YoungGrumpy Junior Member

    Bruce,
    I can not argue with your logic, I even mostly agree with you. However, from what I've red, specifically, R. Woods made a comment that monos mainsail is a poor choice for a cat. I am currently looking around, but the market is poor for a used multis, at least I did not found one yet.
    If I see one close enough, (off course, I am trying to figure out what is "close enough") I will get it
     
  10. gonzo
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    gonzo Senior Member

    You should be able to find a mast or boom from a junked boat in your area now.
     
  11. YoungGrumpy
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    YoungGrumpy Junior Member

    Yes,
    thats my logic. Either a boom, or smaller boat's mast that I can cut and use the front/end fittings,
    So here we are again to the main question:
    How long?
    Secondary one: what are the loads on the boom on the cat this size, and how light I can go?:D
     
  12. teamvmg
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    teamvmg Senior Member

    Is your mast rotating?

    If it is, the boom needs to be long so that the mainsheet angles aft and compresses the boom forcing the mast to rotate.

    I made my boom a bit short and am just adding about 125mm to it to get rotation
     
  13. bruceb
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    bruceb Senior Member

    mast/sail

    Grumpy, you are correct, many used sails would not be the "best", but functional. I am using a sport boat main which was designed for a much bendier non-rotating mast. With my rotating mast, a little re-cutting and better battens, I have a very powerful main that is working well on my tri, at about half price. I certainly would like to have a custom main, but I need jibs and spinnakers more, and they are hard to find used for a multi. Many of the used sail dealers will let you try a sail, I still think it would be worthwhile. Like most things on boats, fast, durable and economical are usually not compatible:mad: B
     
  14. YoungGrumpy
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    YoungGrumpy Junior Member

    Yes
    it is rotating mast. Got it, bigger boom is better. Thanks.

    Bruce, I would think there are more options for jib? Like, many racing boats with fractional rigs and smaller jibs would work? Same for the spinnakers?
    What boat are you sailing?
     

  15. waikikin
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    waikikin Senior Member

    The mast is rotating, the mast is usually fitted wth a "spanner", the vang is attached to the spanner but close to the mast. Some time ago there was a forum multi.net or similar, some one posted the original rigging & tuning tips for the seawind24. Jeff.
     
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