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Thread: track on booms

  1. #1
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    Default track on booms

    what is the consensus of having track on booms on small boats like the H12/Haven.
    is the extra cost worth ease of rigging,?and any other benefits?
    Do the sails set that much better than good lacing

    The plans call for track but not many seem to.
    advice/opinions welcome
    Frobisher

  2. #2
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    Default Re: track on booms

    Why use a track or lacing? The world's highest-performance small craft, including foiling Moths and A Class cats, don't have either. With modern sailcloth (and that includes modern dacron etc) there's no reason to need either, is there? They just create extra work and friction and reduce the sail shape options. Our biggest boat has a 15' boom with a loose foot, and I can't see any reason to use the track.

  3. #3
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    Default Re: track on booms

    Good point.
    I have three boats with loose footed sails but I want to follow Herreshoff's thinking on my new 12 1/2

  4. #4
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    Default Re: track on booms

    If you intend to keep the sail furled on the boom it can be handy to have it laced or in a track.

  5. #5
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    Default Re: track on booms

    I followed the plans and used a track on my Haven. It seems to work fine, but I do not have any experience with loose footed or laced on mains so I can't provide a comparison. I stow my main on the boom and a couple of sail ties hold it in place.

  6. #6
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    Default Re: track on booms

    Have you a clew outhaul on your track ?Or just laced to hole in boom?

  7. #7
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    Default Re: track on booms

    My Gp14 has a bolt rope track carved into the top of the boom. I imagine it was done with some sort of router when it was built back in 1964
    "If you think you are too small to make a difference, try sleeping with a mosquito"

    -Dalai Lama

  8. #8
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    Default Re: track on booms

    I installed a track on my boom mainly because I had zero experience with lacing or loose footing. The track works fine but I suspect the other two methods would also. I added a clew outhaul because I quickly learned that when the sail is dropped allowing the boom to lower to the transom, it puts a big strain into the sail from clew to the first couple of feet of the luff above the tack. That can't be good for the fabric. So, since I like to drop the boom and let it rest on the transom, the clew outhaul is needed. It cleats on the port side of the boom near the tack. The reefing clew outhaul cleats on the starboard side.

    Jeff

  9. #9
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    Default Re: track on booms

    Quote Originally Posted by Frobisher View Post
    Have you a clew outhaul on your track ?Or just laced to hole in boom?
    Just laced to a hole in the boom.

  10. #10
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    Default Re: track on booms

    The cut of a loose footed sail is very different from the cut of a sail attached to the boom along the length of its foot. In general for a gaff rig (where the head is almost always attached to the gaff) it's more harmonious to have an attached foot. Between head and foot outhauls and the peak and throat halyards, you have amazing shape control for different winds and different points of sail.

  11. #11
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    Default Re: track on booms

    As Ian suggested, on a sail that's intended to to attached to a track the sail will have a foot built in, kind of like a shelf, that allows the sail to take the correct shape, or at the very least will have a built in curve like a luff curve so that when you snug it down to the boom the sail draft is forced into the sail in a way that complements the draft being created by a similar curve built into the luff. I remember reading somewhere years ago that the air sliding down the sail and trying to leave the bottom of it hits that ledge and... something something something. Not sure what.

  12. #12
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    Default Re: track on booms

    Any idea that the "shelf foot" was aerodynamically better has since been disproven, which is why multi-million dollar racing machines don't use them. Nor do foilers. Cutting a "lens foot" or "shelf foot" into the sail is also a not-insignificant expense at times, since it requires an extra panel. Attaching the foot also requires extra complications, even if it's just a bolt rope.

    As an example of the simplicity a loose foot can offer, on our 36 footer (and many bigger boats) the clew is just secured to the boom by a simple velcro strap; the same sort of thing that secures a Laser's clew but in the 36 footer's case it's even simpler. The old track remains there on the boom but does nothing but sometimes get in the way of reefing lines.

    A loose footed sail is given any required shape by simple outhaul tension. A shelf foot can't force draft into a sail because it's just sailcloth and therefore cannot push the sail away from the boom. The forces that allow a shelf foot to take up draft also apply to a loose footed sail, but the latter's draft isn't limited by the fact that it's attached to the boom.

  13. #13
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    Default Re: track on booms

    Quote Originally Posted by Frobisher View Post
    Good point.
    I have three boats with loose footed sails but I want to follow Herreshoff's thinking on my new 12 1/2
    Ah, I completely understand your desire to remain true to the designer's thinking. Cheers.

  14. #14
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    Default Re: track on booms

    Old Nat would have a loose footed on his. The design has been around for 106 years. Gaff Rigged, wishbone or marconi has been argued about for a long time. You sound like you have a lovely already modified 12 most likely a Joel White derivative who moved it towards his tastes. Since I doubt you are using cotton sails - i would do what makes the boat faster, easier to rig, and what makes sense in benefits vs thrift/costs.

    If I had deep pockets and access to the racing class - my 12 would be of carbon fiber construction including a carbon marconi rig with loose footed Ultra PE / Carbon / Aramid sails that would mimic the classic look. You can bet you boots the comments from those old guard would be nasty in my victories. It would be exactly what old Nat would have wanted. In the end that would be the only other person I would want to impress.

  15. #15
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    Default Re: track on booms

    We have a gaff rigged class of 20ft LOD, with a boom that hangs way over the stern, they use a laced boom.
    Personally these days I'd go for a loose footed sail these days..

    IIRC the GP 14 boom was made of two pieces with a channel routed in each half then glued together..
    Just an amateur bodging away..

  16. #16
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    Default Re: track on booms

    Ted Hoppe
    What makes you think NH would have loose footed sails.They were used at the time but he chose not to use them.
    I do not have an already modified 12 but am building one ,as close as possible to the original plans which all call for track.
    Chuck Paine with his 12 derivative has carbon mast but still attaching the foot of the sails to booms.
    Last edited by Frobisher; 10-26-2020 at 04:10 AM. Reason: adding clarification

  17. #17
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    Default Re: track on booms

    Perhaps a bit of clarification of terms is in order here. A loose footed sail will generally have some round added to the foot edge. This will add some lower sail draft and is built with some broadseaming (or panel shaping on computer-cut sails) so that the foot is cupped a little bit. The cupping does two things, it keeps the round area from flapping, and also provides a bit of end plate effect, helping to prevent air from sneaking around the sail's bottom (it also looks nicer than a straight foot set loose). Sails work by having higher pressure on one side than they do on the other side, so features preventing the two from equalizing are a good thing.

    Sails attached with tracks along the boom, or which are laced to the boom, are cut differently. They are much straighter along the bottom, with little or no visible round down there. However, it is still important to give that bottom area some draft, and again it is done using round and broadseaming. In this case though, the round is added to the top edge of the bottom panel, which is then sewn to the straight bottom of the panel above it. In the old, lofting on the floor days, for cross-cut sails we would actually loft out the sail with the round on the bottom (like on a loose foot) then cut out the bottom panel with a bit of excess left at the ends, then flip it over and attach the rounded edge to the straight bottom of the panel above it, yielding both the desired draft, and a straight foot edge to attach to the boom. Excess would then be trimmed from the panel's ends to match the luff and leech edges of the lofting. Since these two sail foot types are cut so differently, most experiments where folks are trying to switch types just by attaching their existing sail to the boom, or unlacing it from the boom, are usually not particularly successful.

    Then there is the true shelf foot, which was a hot idea among performance boats for a while (including the 12 Meter AC boats) but which seems to be a lot less common these days. The sails were built with little or no round along the foot edge, like a sail with a track along the boom would have, but then another panel was attached below the foot. This would be made of a soft, mushy fabric, attached along the boom, and it formed a horizontal "shelf" between the boom and the foot panel. Cranking in the outhaul for upwind work would collapse the shelf up against the boom and pull in and flatten the bottom of the sail for better upwind performance. Downwind, the outhaul could be eased, the shelf allowed to relax, and it would yield maximum lower sail draft and built-in endplate effect. On other points of sail, the outhaul could be tensioned as desired to yield whatever amount of draft you wanted in the lower part of the sail.

  18. #18
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    Default Re: track on booms

    Not mentioned so far is that going loose footed means changes in boom design: your load is on a point rather than distributed. Not an issue for short boomed high speed boats with carbon or aluminum. A laced or tracked boom would be lighter; unfortunate things can happen to a boom not meant for a loose footed sail.

    Tracked racing sails are often meant to be removed after a day sailing.
    Ben Fuller
    Ran Tan, Liten Kuhling, Tipsy, Tippy, Josef W., Merry Mouth, Imp, Macavity, Look Far, Flash and a quiver of other 'yaks.
    "Bound fast is boatless man."

  19. #19
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    Default Re: track on booms

    Yeah, long skinny booms rely on load spread by lacing or track and can go noodle like without. I'd be using lacing or robands ,or beefing the scantlings 5 or 10 % and go without.
    Then again, its a small boat so maybe it's fine. I'll be looking at a haven on the weekend as it happens, I'll see what they did.

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