Mainsail sheeting design without a track.

Discussion in 'Sailboats' started by Omeron, Nov 10, 2008.

  1. Omeron
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    Omeron Senior Member

    I am trying to find a suitable mainsail sheeting arrangement which can do without a mainsail track, but still provide some control with the twist of the mainsail.
    Boat is approx 12.m with a relatively big main.
    Mainsail sheeting is to be behind the helmsman, and should be controlled by the helmsman for shorthanded sailing.
    The attached pictures i found somehow gets close to it. But with this arrangement i cannot exactly understand why there is a track. Since most of the tensions are provided by the two sets of lines going to either side.
    Can a similar system be designed but without the track.
    I still prefer two control lines on either side rather than a single line in the middle.
     

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  2. Martini
    Joined: Nov 2008
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    Martini New Member

    I am no expert, but i have pondered the same thought. the one thing that comes to mind is found, well i found this systemn on a clipper(I think its a clipper - big training ship with a few square rigs).

    One would have two mainsheets, working from both sides of the boat. the one sheet hauls in/across and the other hauls downward. you have your mains played from both sides, and you dont have a track,

    Its just an idea, and i realise the clutter two mainsheets would cause. I attached a simple sketch to illustrate my idea... even though its a bad idea, it might give you a better one :)

    P.S. I have the same sort of problem on a dinghy Im building, well there's no space or hardpoints (sept gunnels which are oo far apart) for the mains, let alone a track

    but why cant you have a track?
    cause your solution might help me ;)
     
  3. kenJ
    Joined: Jul 2005
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    kenJ Senior Member

    The system as shown in the pictures allows the mainsheet to control the tension (twist) on the sail and the traveller allows trimming of the sails angle of attack to increase or decrease the sail's power. I am sure there are other ways of doing what you want, the one that jumps out at me is to secure the mainsheets at the boom and run one to each side using a jam cleat to hold it. The leeward sheet would stay loose, the upwind sheet would adjust the angle of attack, you would need a vang to control the twist. Be a pain to tack, would have a sheet for each sail that would need to be hauled in.
     
  4. Omeron
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    Omeron Senior Member

    Hi kenJ,
    From the picture, i cannot tell whether it is the same rope going through all the blocks or two independent ones. If it is the same, then i cannot see how adjusting the car would change angle of attack,as you tension the sheet, it shortens the distance and brings the boom end down as well as to a side.
    If they are independent, and bring the car to lets say leeward,and tension it,it takes the twist off, but then it does not let other sheets to move the boom to adjust the angle, because it restricts the boom end just as a single point mainsheet system.
    I find their interaction a little confusing. If you already have the track, and can adjust the car,why do you have the side sheets? or vice versa.

    The reason i do not want to have a track is because, behind the wheel, i have a seat for the helmsman which doubles as a locker with a top openning.

    If i have the track forward of the wheel,it is difficult for adjusting singlehandedly and block the passage way. If mounted on the floor, the sheets rub the cockpit coamings when boom opens up.
     
  5. Omeron
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    Omeron Senior Member

    I guess, if you have a strong enough vang to control the twist,things become simpler in terms of adjusting the angle. But the vang has to be a beast to pull down a monster of a boom doesnt it?
    In the old days, boats had a loose rope near the transom with a riding block on it. The main sheet attached to that riding block, and when tensioned, it assumed an inverted tilted V shape. I guess it was there as a cross between a mainsheet and a track. Can this be revived and put to some use do you think?
     
  6. Stumble
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    Stumble Senior Member

    The boats I have seen without a track normally just have an eye bolt in the middle of the deck, but this of course doesn't allow very fine control over the main. My thoughts would be to run two mainsheets from padeyes on the toe rail. This should allow you to control the boom to some degree by playing thw two sheets against themselves.

    If you are set on not having a track this would be the best system I can think off. But I would recomend against it, since not only do you give up control over the main compared to a traveller, it would likely be at least as expensive as a track, perhaps even more by the time you pay for the extra line and hardware.
     
  7. diwebb
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    diwebb Senior Member

    Hi,
    another possible solution is to have the single point mainsheet attachment and control sail twist with a vang attached between a third and half of the way forward from the outboard end of the boom. If a double block is attached to the boom and separate vang sheets go to a single block with becket at each gunwale, then twist can be controlled quite easily. The only thing to remember is that they must be let go before tacking. I have used this system on a gaffer with a mainsheet horse similar to the arrangement you showed in the photos, and it worked very well in controlling twist in the main. It does, however, mean extra lines across the cockpit or aft end of the cabin. They can be brought back to the helm position for single handed sailing.
    David
     
  8. catsketcher
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    catsketcher Senior Member

    Go the vang

    If you really want to get rid of the track you need a vang and a solid boom. This is pretty easy in small sizes and just engineering in larger boats - almost all modern dinghies have rid themselves of the mainsheet track and sheet in and out with the sheet and control twist with the vang. To get the same effect as pulling the track to windward in light weather use a rope bridle at the end of the boom. This raises the pulley and has the same effect as dragging the track up. You could get a little clever and alter the bridle as the wind increased to get the pulley where you want - like a Laser in heavier air.

    Another way is to go to a wishbone boom - I did this on my 38ft cat but cats have high sheet loads and mostly can't fit vangs. You can instead use a solid vang which can act as a topping lift when you drop the main.

    cheers

    Phil Thompson
     
  9. rfnk
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    rfnk Junior Member

    Here's a solution that, personally, I'd never use! Modern Folkboats have a track that runs across the cockpit in front of the helmsman. The sail control provided is impressive but the inconvenience isn't!

    Some boats have a track mounted on a raised bar across the lazarette. This would give you all the advantages of a track (i.e., control and simplicity) and still allow access to your locker, perhaps. The raised bar can be designed to be attractive - depends on your particular boat.
     
  10. Omeron
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    Omeron Senior Member

    I also found this. Pictures are not aimed at the mainsail arrangement, but makes you wonder still. What are your comments?
     

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  11. kenJ
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    kenJ Senior Member

    From the pictures on the Saffier web site it appears that the mainsheet is continous. It is very hard to tell, but it looks like the mainsheet can be adjusted without the use of a winch (unless there is hidden routing forward to the winches forward of the helm). Keeping mainsheet loads low is a benefit of boom end sheeting. Once the mainsheet is set, the blocks in the vertical part of the mainsheet should keep the mainsheet tension the same when adjusting the traveller.
     
  12. Splash Gordon
    Joined: Apr 2008
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    Splash Gordon Junior Member

    Beast-boats like this just DON'T "do" downwind, a la the Open60's, so they don't ever ease sheets like plebian cruisers do. They're in a permanent reach-mode, so all the mainsheet does is haul the boom down.
    The Catamaran-style mainsheet with two tackles uses two mainsheets, one at either quarter which alternate duty as vang and afterbrace. It's a bit of a fiddle to use, but it's about the only track-less solution that will give one the control you get used to with a track...
     
  13. JesperW
    Joined: May 2006
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    JesperW http://journeyman.se

    One thing to keep in mind when considering a dual sheet system is that in case of a broach (when the sheets need to be let out rapidly in order not to loose control of the boat) you now have two sheets to release before the boom can swing out.

    Safety concerns made me go for the "large vang + stiff boom" solution...

    Omeron, by the way, what is that yacht in the picture? I liked it :) !
     
  14. Omeron
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    Omeron Senior Member

    It is definately French! But unfortunately i do not know what it is, and cannot remember where i downloaded it from. Most probably from one of the threads of Sailing Anarchy.
    As far as the mainsheet goes, you are right. But if you make sure that the leeward sheet is always idle, and not tensioned, releasing the windward side should be enough to get you out of trouble, unless ofcourse you are decidedly broaching, and should let go any piece of rope you can lay your hands to. :)
     

  15. JesperW
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    JesperW http://journeyman.se

    yeah, well... except when going close-hauled in lots of wind (most likely moment for upwind broaches!) you will have the leeward sheet tensioned as well, to get a flat sail... ;)
     
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