Making a "Park Avenue" Boom

Discussion in 'Multihulls' started by Meanz Beanz, Jun 27, 2007.

  1. Meanz Beanz
    Joined: Jun 2007
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    Location: Lower East ?

    Meanz Beanz Boom Doom Gloom Boom

    LOL yeah if the boat was big enough that would be great!

    Being a cat the boom rarely meets the shrouds, you tend to reach everywhere as its quicker! In fact I must admit I don't know if the mainsheet goes far enough!

    Still puzzling over this one.

    Cheers
    MBz
     
  2. Meanz Beanz
    Joined: Jun 2007
    Posts: 2,280
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    Location: Lower East ?

    Meanz Beanz Boom Doom Gloom Boom

    Now thats a thought!... I will have to get the sketch pad out and doodle!

    Thanks

    MBz
     
  3. Meanz Beanz
    Joined: Jun 2007
    Posts: 2,280
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    Location: Lower East ?

    Meanz Beanz Boom Doom Gloom Boom

    Sounds reasonable for my boat ! Misses out on the water catching idea but for a small cat it is light weight and practical.

    Cheers
    MBz

    PS. Sorry about the tardy replies... emails not getting to me????
     
  4. eponodyne
    Joined: Aug 2007
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    Location: Upper Midwest

    eponodyne Senior Member

    I kind of like Alan White's idea (great minds think alike, and hey, ours do too...); build it exactly like the wing tip of a tube-and-rag homebuilt airplane. You could even use Ceconite to cover!
     
  5. scupper
    Joined: Jun 2010
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    Location: British Columbia

    scupper Junior Member

    I've been thinking of building one of these. Mainly I'm concerned with ease of building and I'd rather it never broke. So far the plan I've come up with is, for my 300 square foot main with a foot of just under 14' would be to find a nice piece of aluminium angle iron, like 8"x8" probably 3/16" or 1/4". Weld some flat bar or some plate across the hypotenuse of the triangle, along it every six inches or so. I figured this would be something I could have a shop weld up for me in a half hour or so if I just cut all the gussets out. For my reefing blocks I was thinking I could just run a bolt horizontally though the angled sides of the boom and just make some some beveled bits of plastic to tighten the nut against,you could put the sheave on the bolt and I guess you'd have to pop rivet some cheeks around each sheave. But this would get rid of the issue I've being having about whether I run my lines inside or outside of the boom. This would let me just run them along the inside of the boom which would be pretty much open except for the flat bar every six inches. My current boom is five inch sch. 40 pipe so an 8x8 would be much of a change.
    If anyone's still following this thread I appreciate your thoughts.
     
  6. scupper
    Joined: Jun 2010
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    Location: British Columbia

    scupper Junior Member

    Another thing that pointed me in the direction of a wide boom was I remember reading in some sail trim book that having a wider boom along the foot helps to seal in the surface pressure along the sail rather than just to let it spill out over the foot and so helps to keep in the lift. Much like wing tips on a plane of a keel for that matter.
     

  7. michael pierzga
    Joined: Dec 2008
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    Location: spain

    michael pierzga Senior Member

    Didnt read all the replies but a simple " T " shaped boom is also elegant and simple to build. The structural part of the boom is a vertical box section , tapered in the ends. The "T" , horizontal section wings , are a secondary structure to hold the lazy jacks and give a platform for the flaked main to rest The T boom is simple because all the reef lines can be led on the outside of the main boom structure and the " wings can be a secondary bond because they carry little load..

    Lazy jacks on " spreaders " growing out of the side of the boom to give a nice platform for the main to flake never work well. Spin sheets and lines catch the lazy jack spreaders , the flaked sail sags between jacks , reef line get tangled......
     
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