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Canting the sail - upwind?

  • 25 Nov 2016 19:35
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    Reply # 4411426 on 4407967
    Anonymous member

    Thanks everyone for that.  Balance upwind is fine - but it would, maybe, be nice to explore a wee bit more edge to upwind performance.  Maybe..... .Not all boats benefit from sailing on their ears, after all.  But if I did add an extra yard sling point, how far aft should it be ?  How about a foot, approximately?


    PS

    At 56 North, 19.33 GMT, I crouch before my stick fire and dream of launch, next April.  And also study the line-drawings in Worcester Sail and Sweep in China.  I notice that just about every sail is rigged with a single, full-hoist, running luff-parrel, rigged to spans from the throat to the lowest batten.


    seasonal greetings to all.

    IFG
  • 24 Nov 2016 10:41
    Quote
    Reply # 4409322 on 4407967
    Anonymous member

    When I converted Arion to junk rig in 2011, I used the sail plan from my junk-rigged sistership, Minke.  I knew from sailing Minke that she had more weatherhelm than Arion did under bermudian rig.  I also noted that the CE or centre of area of Minke's sail was about 300mm further aft than Arion's bermudian rig.  I had to put the mast partners in the same place as Minke's on deck, so I canted the mast forward by 3 degrees.  This was achieved by moving the mast step aft, which placed the CE of Arion's new junk sail in the same place as it was under bermudian rig (Minke's mast is vertical).  The balance has proved to be exactly the same as it was under the bermudian rig, which is near perfect.

    So, to quantify it, the mast is 8.5m above deck and sets a 35 sq metre sail (4.6m across the battens).  Raking the mast forward by three degrees moved the CE or area forward by 300mm.
  • 24 Nov 2016 04:38
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    Reply # 4408964 on 4407967
    Deleted user

    I have had quite a lot of experience with this. When I first fitted the new sail to Footprints I had the sail canted forward even to windward to reduce the weather helm. It worked OK but there are some potential problems, most of which is that in canting the sail forward the aft end of the sail drops down so there may be problems with the aft end of the boom and main sheet becoming caught on various things at the aft end of the boat. 

    Another option might be to do as Arne suggests and that is move the whole sail forward to create more balance. But this will likely necessitate moving the sling point on the yard further aft which also results in the sail sitting lower on the mast, so do you have sufficient clearance between the bottom of the sail and the cabin top to do this, or can the sail be hoisted further up the mast and still retain sufficient halyard drift.

    On Footprints I solved the weather helm problem by canting the whole mast forward by 500mm at the top. This was not as difficult as it might sound, on Footprints it meant moving the mast step 80mm aft. The result was that the centre of effort of the sail was moved forward to where it should be.


    Last modified: 24 Nov 2016 04:40 | Deleted user
  • 23 Nov 2016 20:04
    Quote
    Reply # 4408288 on 4407967
    Anonymous member (Administrator)

    Iain

    I notice that you have set your sail with very little balance. If you have too much weather helm when close-hauled, I suggest you shift the whole sail a bit further forward, but keep the luff and leech parallel to the mast. This was what i did to my Ingeborg's sail to trim out weather helm.

    Arne
  • 23 Nov 2016 17:28
    Quote
    Message # 4407967
    Anonymous member
    Can a sail which is rigged to cant off wind be also canted upwind, in theory and/practice?  Presumably, easing the sail forward on the mast would tend to trim-out any weather-helm.  Or is there more to it than this?
    Moved from The Yacht Club Bar: 26 Nov 2016 22:03
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