Aluminium Yards and Booms

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  • 03 Mar 2012 03:52
    Reply # 842572 on 839228
    Being time rich and money poor it's going to have to be timber as my only costs will be material and those will be around $100. That's for the Yard and the Boom. At least they will match my clear finished mast.
  • 03 Mar 2012 01:39
    Reply # 842463 on 842452
    Robert Groves wrote:The yards on Easy Go are 3 inch by 1/4 inch tubing. The battens are 1 inch by 1/8 inch tubing. Sorry I can't convert these to metric. They have many thousands of miles on them and are doing a great job so far. The yards have rope loops to the halyards that have worked flawlessly. No need for fancy fabrication.

    Depends if you are trying to save weight or not. Also you have a flat sail so you get away with small battens, they would not work with a cambered sail such as Gary has.
  • 03 Mar 2012 01:28
    Reply # 842452 on 839228
    Deleted user
    The yards on Easy Go are 3 inch by 1/4 inch tubing. The battens are 1 inch by 1/8 inch tubing. Sorry I can't convert these to metric. They have many thousands of miles on them and are doing a great job so far. The yards have rope loops to the halyards that have worked flawlessly. No need for fancy fabrication.
  • 03 Mar 2012 01:27
    Reply # 842451 on 839228
    Gary, 65x3 T5 would work, as would 75x2 T5.
  • 02 Mar 2012 10:42
    Reply # 841643 on 839228
    Okay, slight reality check The nearest T6 I can get is 63.5 x 6.35 which is a fairly thick wall and is $23.18 + GST per metre. That comes to $131. The tension tube will cost me around $21, then there is the Boom and the welding.
    So I'm having another look at timber. I can get enough recycled 150mm x 37mm Oregon to laminate a Yard and a Boom for around $80. And I have enough epoxy to glue it up. A mate has offered to thickness the timber for me so I think I will go with it.

    Gary
  • 01 Mar 2012 21:01
    Reply # 841157 on 839228
    Thanks again Paul for the fine detail. I wasn't going to worry about getting it anodised. I was going to try an idea I have read about, namely rubbing it down with car wax polish, apparently it protects Aluminium quite well.
  • 01 Mar 2012 18:20
    Reply # 840993 on 839228
    Gary,

    You should try and get aluminium in grade 6063 T6 for the main tube (T5 (more common) is OK for the tension tube as it just in tension, does not have to deal with bending but T6 will not hurt if you can get it). In NZ T6 is generally very hard to get (unless you specially order it, minimum order 120kgs) So I used blank dinghy masts which are readily available from the local rigger in the correct grade. If you cannot source T6  and have to use T5, you should go up at least one size in diameter.

    Two changes you should make:

    a) Make the riser (plate between the main tube and tension tube) about 50mm taller. You want the angle between the main tube and the tension tube to be 8deg or greater

    b) Extend the tension tube to within about 100mm of the ends. This will put the tension tube under load earlier and should make things stiffer.

    Lastly when you tack the tension tube to the main tube before starting the full welding, put some pre-bend in the main tube (the bend should be away from the tension tube) this is because when you weld up the two, the main tube tends bend upwards due to weld shrinkage.

    PS. You could make the ends simpler by just making plastic or even wooden bungs to close the ends. Then you can just dill holes for your lashings, also avoids arguments with the anodiser who will want to drill holes in you nicely sealed ends.

    PPS:I'd normally make the yard about a 200mm longer than the sail to allow for stretch and unknowns.

    PPPS. For Annie's boom batten, I used a 50mm dinghy mast.
  • 01 Mar 2012 10:14
    Reply # 840621 on 840418
    Gary Pick wrote:Paul I've downloaded the drawings and printed them out, I have say I'm very impressed. I think I will just go with the same dimensions apart from making it a bit longer for my sail. One question, how much outhaul did you allow for the throat and the peak? I don't know the dimensions of Annie's sail.
    Cheers, Gary

    It's okay I used my brains and looked at Annie's sail plan.
  • 01 Mar 2012 09:24
    Reply # 840418 on 839228
    Paul I've downloaded the drawings and printed them out, I have say I'm very impressed. I think I will just go with the same dimensions apart from making it a bit longer for my sail. One question, how much outhaul did you allow for the throat and the peak? I don't know the dimensions of Annie's sail.
    Cheers, Gary
  • 01 Mar 2012 01:38
    Reply # 840004 on 839228
    Thank you Paul, I will DL the drawings. You've told me just what i wanted to know.
    Cheers, Gary
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