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Thread: Determining the size of a staysail club

  1. #1
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    Default Determining the size of a staysail club

    I'm rigging a staysail on my 33 ft, 9 ton boat, which will have approximate dimensions of 23x8 ft. I'm interested in making a club for the sail, but I don't always plan on using it, so the sail I make will likely be loose footed. I hear club footed jibs and staysails get better shape being loose footed also.

    The sail will be no larger than 100 sq ft. Most likely, it will be 85 or 90 sq ft. I'll be using what I believe to be sitka spruce to make the spar. I dug an old hollow wooden mast out of the woods at my boatyard and cut it into sections. I've searched (here and google) on how to determine the size of a spar, but I haven't turned up much. Most articles are about how to actually make the spar, which is useful, but not what I'm trying to figure out. Can anyone enlighten me? Also, does the cut of the sail influence the dimensions of the club? I'd like to keep it rectangular, and I have a small cranse iron of 2.5" ID that I could use at clew the end. I'm considering rigging lazy jacks.

    Regardless of how it's rigged, can anyone tell me how to determine the appropriate dimensions of a spar? Do I need to provide any more info that I haven't already?

  2. #2
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    Default Re: Determining the size of a staysail club

    There's a few different ways of going. You can be pretty analytical or general.


    A couple general approaches.

    Ian Oughtred's Boat Building Manual has a section on spar design.
    For a Boom:
    Diameter is 1:56
    Taper: heel 80-85% - peak 70%

    John Leather's The Gaff Rig Handbook
    Solid Booms, loose footed sail diameter 0.022 maximum tapered to about 0.02 at the ends.

    So that puts you about 1.8% for smaller boats to about 2.2 percent for traditional larger boats. You could probably split the difference for yours and make some adjustments based on the type of wood you are using.

    Travis.

  3. #3
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    Default Re: Determining the size of a staysail club

    Cool, thanks Travis. So my boom being roughly 8.5 ft long, my diameter should be about 1.75", which is about what I was thinking. I think maybe add about an inch to the height? Per John Leather's book, what do the maximum taper numbers refer to? Is that .02" per foot? How do I find out where the taper starts?

    I think I could just wing it if I know the maximum dimensions are sufficient. I could just do a minimal taper, maybe starting 2/3 of the way back from the gooseneck, to keep things strong enough.

    -other Travis

  4. #4
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    Default Re: Determining the size of a staysail club

    Woodwinds stay sl boom is a tee spar of 1 " Sitka .4" wide and 3"deep. Quite a bit stronger than 1.75"!! Small wood jaws forward that go around the bottlescrew with a bolt . The back end just has a hole, no fitting. You want to be getting hit by a bronze fitting when you are doing stuff up there? Two strings tied around the boom for furling, ". One string from the aft end ties up to the fwd shroud. No topping lift or lazy jacks.
    Last edited by wizbang 13; 03-20-2017 at 03:19 AM.

  5. #5
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    Default Re: Determining the size of a staysail club

    Good point about getting hit with a bronze fitting, and the ear of a cranse iron would really smart! How big is the staysail on Wizbang? Maybe I'll laminate two pieces of 1.5" together and shape it from there. When you say 4" wide, 3" deep, do you mean that the 4" area is on the lateral plane, not the vertical plane? So the widest part takes the side to side loads?

    I found this site late last night, which aside from learning how to properly taper a spar, has an enormous amount of info. http://www.boat-building.org/learn-s...oom-gaff-spar/ It's full of articles about how to do things, with pictures and video. Very cool website.

  6. #6
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    Default Re: Determining the size of a staysail club

    Yes,4x3 at the widest point, middle. Consider that you do not even want a staysl topping lift, never mind need one. When you raise or drop it at sea, you want it over to the side, as there is no room to do stuff otherwise. Once anchored or docked, put it where you want it, but that would still be off to one side, probably not in the center.
    Woodwind is only a little bigger thanZuri.
    I am underway now, Marie gallant to Guadeloupe. I will put up some pics when we get better wifi that I just took to show you some stuff.

  7. #7
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    Default Re: Determining the size of a staysail club

    Wizbang is an older 2cycle speedboat. My main ride is Woodwind, 34' gaff ketch

  8. #8
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    Default Re: Determining the size of a staysail club

    Quote Originally Posted by wizbang 13 View Post
    Yes,4x3 at the widest point, middle. Consider that you do not even want a staysl topping lift, never mind need one. When you raise or drop it at sea, you want it over to the side, as there is no room to do stuff otherwise. Once anchored or docked, put it where you want it, but that would still be off to one side, probably not in the center.
    Woodwind is only a little bigger thanZuri.
    I am underway now, Marie gallant to Guadeloupe. I will put up some pics when we get better wifi that I just took to show you some stuff.
    Edit.... I got you two , zuri and train mixed up again.

  9. #9
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    Default Re: Determining the size of a staysail club

    "Modern Boatbuilding" by Edwin Monk NA, 1942, p93 has:-


    Staysail boom


    Spar diameter in inches = 0.020 x spar length in inches.

    Tack end = 0.75 x spar diameter.

    Clew end = .667 x spar diameter.



    By way of scantling comparison to what you already have he gives main boom diameters

    Boom diameter in inches = 0.16 x spar length in inches.

    Tack end = 0.80 x spar diameter.

    Clew end = 0.7 x spar diameter.

  10. #10
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    Default Re: Determining the size of a staysail club

    looking down at the tack of woodwinds staysl and jaw of boom

    staysl furled and boom pulled up and tied to stbd. shroud jib poled out . stsaysl comes down when off the wind usually. high tech jib pole

    staysl clew on boom , no fancy fitting. quiet, cheap and safe

    crappy photo of nothing in particulart

  11. #11
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    Default Re: Determining the size of a staysail club

    Interesting. I suppose that's about as simple as it gets. How long has that staysail club been there? It looks like the jaws of the club would get eaten up by the turnbuckle over time when the club swings across during a tack. The clew of your sail is... really something. That's an interesting club design though. Simple as can be, but looks like it provides a lot rigidity in both directions. I like it more each time I look at it.

  12. #12
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    Default Re: Determining the size of a staysail club

    That tee boom has been there since 1984 . 70,000 miles . It does not chafe the jaw,as the bolt goes through the bottlescrew, so the bottle screw turns a bit when the boom goes side to side.
    Oh yea, I recon Todd or Carol Hasse would not approve of the clew of my $40 sail. I keep meaning to stitch some nylon webbing on there, ....one of these years.
    As soon as I turn off the wind I drop the staysl, it just blocks the jib. But yes, for downwind shape, a pedestal further aft is more stuff to maintain and trip over I mean something that helps with belly.
    It has a jack line halfway up, in order to come down.
    In snotty wind when the topsl comes down I move the staysl halyard over to the topsl halyard winch, which is a herky Murray.
    All that said, I am playing with a half wishbone boom on my smaller boat that works better off wind, self vanging.
    Mostly I wanted to show how simple things can be.
    bruce
    Last edited by wizbang 13; 03-22-2017 at 04:09 AM.

  13. #13
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    Default Re: Determining the size of a staysail club

    Bruce, I can appreciate a $40 sail. I see what you mean about the jaws of the club too. I'll be making my staysail out of scraps of a discarded main and I feel pretty good about my ability to hand sew grommets. The grommets on my ditty bag are fairly pretty, I think. I bought a second hand Read's machine for $200, which I've been using in hand crank mode, though it came with a 24v motor, but I don't have a 24v system on my boat, and I'm not sure whether I want to buy two small batteries and connect them in series, or just get a 12v motor. Kinda doesn't make sense to set up a 24v system for just the machine I think, but maybe there's other 24v stuff to have. But I like how simple my boat is. 12v power, a solar panel, no shorepower, no battery charger, no inverter.

    Anyways, I've been itching to start sewing my staysail, but I haven't gotten that far yet. Until I have my bowsprit in place with the inner forestay installed, and until I build the club, I won't know the exact dimensions of the staysail. The inner forestay will be moved in from the stem by three feet, leaving six feet between the jibstay and the inner forestay. I think that should make tacking a little easier and the jib won't be blocked as much. Might take the six foot pennant off the top of the jib and put it on the bottom to get it higher and out of the way of the staysail. Kind of a half assed flying jib.

    As for jacklines, I've always just had my downhaul clipped into the grommet just below the head on the luff, and when I give that a tug, it all comes down. I've never used a jackline and I was considering putting one on my staysail, but my jib on this boat and my previous boat came down just fine without one. If that's the case, what are the advantages of a jackline? I know their intended purpose, but I've never seen the need for one. Maybe it doesn't work the same with all sails and boats.

  14. #14
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    Default Re: Determining the size of a staysail club

    Hopefully I can get the grommets on my staysail to look like this:



    That will be a lot of grommets to lay up and sew, even on a 90 sq ft sail. Something to do in the evenings with a beer or glass of rum, since I don't have a TV.

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