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Weather Helm - Sail Cut & Trim

Discussion in 'Sail Trim with Don Guillette' started by Tim22, Aug 4, 2016. Add this thread to a FAQ

  1. Tim22

    Tim22

    Joined Jun 16, 2014
    167 posts, 14 likes
    Hunter 310
    CA Ottawa
    Two years ago I acquired a 1997 Hunter 310. As part of refitting I bought a new suit of sails. The main is loose footed and full battened and the jib is 110% with the height of the clew slightly above the lifelines.

    I am finding that the boat carries substantial weather helm at wind speeds as low as 9 to 10 knots and becomes excessive ( rounding up) at about 12 knots. In an effort to correct the problem I bought Don's very good book on sail trim and this evening, in 10 to 14 knots of wind we tested the various methods recommended to move the draught forward and reduce weather helm. Moving the traveller to leeward, tightening down the Cunningham, and adjusting the vang all made slight differences but not to the extent required.

    I am now looking at the cut of the main sail and wondering if having it re cut a bit flatter and reducing the roach might help.

    The boat is a B&R fractional rig.

    I would be grateful of any suggestions that might help to resolve this.

    Thanks
    Tim
     


  2. Stu Jackson

    Stu Jackson

    Joined Feb 26, 2004
    19,906 posts, 575 likes
    Catalina 34
    224 CA Maple Bay, BC, Canada
    Tim, with a loose footed main, can you explain why you can't get the main flat, flat, flat without a recut? What would you recut on a loose footed main?
     


  3. Tim22

    Tim22

    Joined Jun 16, 2014
    167 posts, 14 likes
    Hunter 310
    CA Ottawa
    Hi Stu - thanks for your reply. I can get good tension on the foot of the sail. The sail, however, seems to have a rather large belly which I had thought would be removed by tensioning the Cunningham and while it is reduced, it is still quite substantial.

    My other thought is that reducing the roach near the top of the sail might help.

    Tim
     


  4. Stu Jackson

    Stu Jackson

    Joined Feb 26, 2004
    19,906 posts, 575 likes
    Catalina 34
    224 CA Maple Bay, BC, Canada
    Tim

    Please re-read Don's excellent book. The cunningham tightens the leech, and does little (but some) to the draft.

    Tighten your outhaul. Flatten your sail.
    Nope, please, don't do that to a new sail.

    Wait, study, practice some more.

    Please.
     


  5. Tim22

    Tim22

    Joined Jun 16, 2014
    167 posts, 14 likes
    Hunter 310
    CA Ottawa
    Hi Stu
    I believe you are mistaken. The Cunningham tensions the luff.

    Tim
     


  6. Joe

    Joe

    Joined Jun 1, 2004
    6,467 posts, 325 likes
    Catalina 27
    US Mission Bay, San Diego
    You can impart more pre bend in the mast to remove some of the draft. However, I would first check my mast rake, which is a primary mast tuning step. Raking the mast moves the center of effort aft... which has a huge effect on weather helm. The owner's manual for your B&R rig will have instructions on how to measure and set your mast's rake... it's the first thing you do when tuning the rig... it will also tell you how to set your pre bend. My experience with boats without backstays is limited to my Nacra beach cat.. but... the principles are the same... So I recommend you take a close look at the B&R rig tuning guide for the fine points.
     


  7. Stu Jackson

    Stu Jackson

    Joined Feb 26, 2004
    19,906 posts, 575 likes
    Catalina 34
    224 CA Maple Bay, BC, Canada
    Tim, sorry, my-bad-fingers. Of course, you're right.
     


  8. shemandr

    shemandr

    Joined Jan 1, 2006
    3,478 posts, 564 likes
    Marblehead Skiff 14'
    US Greenport, NY
    What Joe said. I would add that if the main is cut for pre-bend and there is no pre-bend you are going to have too much belly as you describe. Outhaul and cunningham won't fix it. Since you paid Doyle for the sails, it's entirely appropriate for you to contact them and say you are having a problem. Did they measure the boat?
     


  9. Justin_NSA

    Justin_NSA

    Joined Jul 7, 2004
    4,622 posts, 700 likes
    Hunter 30T
    US Cheney, KS
    If it won't flatten, is it possible that the leech is too long? Interesting thread for a change.
     


  10. Tim22

    Tim22

    Joined Jun 16, 2014
    167 posts, 14 likes
    Hunter 310
    CA Ottawa
    Doyle did measure the boat. There is currently very little, if any, rake on the mast. As the mast is removed for the winter it is quite possible that the pre bend is different from when they measured so I will investigate this further as there is certainly room to add a bit more bend.

    I also replaced the forestay to accommodate a new furler so this may have affected the rake. My understanding, however, is that increasing the rake will increase weather helm so given my current no rake situation this would seem not to be a contributing factor.

    I did follow the B&R instructions when tuning the rig but found that the prebend tension on the diamond stays was greatly reduced once the rest of the rig was tensioned. One of the things I find most difficult is how to get sufficient forestay tension without the backstay.

    Thanks
    Tim
     


  11. JamesG161

    JamesG161

    Joined Feb 14, 2014
    2,896 posts, 838 likes
    Hunter 430
    US Waveland, MS
    Ours is a 430, but I several private chats about the series of Hunter's that end in a "0" this appears to be a characteristic of our Hull shape to Mast position design.
    I recently had the opportunity to run/test our boat at winds speed of up to 25 knots in light seas, new Main and OEM jib.
    Since this is the first B&R rig I have ever run, plus we have in-mast main sail, bottom line we are still learning our "Cruiser" (not racer even though we are PHRF rated).

    As the weather helm took all my strength to hold course, she nosed down and healed to spill the wind out of the main. SOG 8 knots. What a ride!

    So far my conclusion is to reduce the head sail area. Thus your 110% may be too much for your boat.
    My disclaimer is that I am still learning, but we had nice balance with our sails at 15 knot sustained and 1 foot seas.
    Jim...

    PS: B&R rigged Mains take them more out of the balance equation than I would have guessed.
     


  12. JohnVTX

    JohnVTX

    Joined Jul 14, 2015
    840 posts, 131 likes
    Catalina 30
    US Stillhouse Hollow Marina
    If you are getting too much weather helm, you also need to utilize your main traveler if you have one. Trim the main and move traveler to leeward to stop helm. Once main is trimmed, the traveler should be your main, if not only adjustment you need going upwind.
     


  13. Tim22

    Tim22

    Joined Jun 16, 2014
    167 posts, 14 likes
    Hunter 310
    CA Ottawa
    I don't think it's a leech problem as it appears to be cut properly and to spec.

    This brings up another possibility. When I ordered the sails Doyle suggested the main at 294sq ft and the jib at 220 sq ft. The Hunter specs were for the main at 308 sq ft and the jib at 220 sq ft. Because of the discrepancy we increased the area to the Hunter specs. The extra on the main was added to the roach and on the jib it was added to the LP measurement. In retrospect this may have been a mistake if it is contributing to that problem. I should add that I asked for the change so this should not reflect on Doyle.

    Tim
     


  14. Charles Erwin

    Charles Erwin

    Joined Jan 30, 2012
    958 posts, 103 likes
    Nor'Sea 27 - "Kiwanda"
    US Portland/Anacortes
    It is not likely that good sail trim can overcome bad rig set up and tension.

    Mast rake - tip it forward. Mast pre-bend to match the luff curve that the sailmaker gave you - bend in the middle until you see wrinkles form then slack off until the mainsail fabric lays true. Last comes sail trim. By the way backstay tension (if you have one - Tim22 does not ) needs to be kept neutral for these adjustments. Mast rake will have the most dramatic effect.

    If your results are not effective have a sail maker or skilled dock mate visit/sail the boat and show you how to do these things - the Doyle rep would be a good place to start. Also review this:

    http://www.riggingandsails.com/pdf/selden-tuning.pdf

    One hopes these suggestions will help make the boat behave. We could do with a report about what happens.

    Charles
     


    Last edited: Aug 5, 2016
  15. DougM

    DougM

    Joined Jul 24, 2005
    1,499 posts, 129 likes
    Beneteau 323
    US Manistee, MI
    Every boat is different for certain.
    Start by getting your halyard tension where it should be, no wrinkles in the luff.
    Tighten the forestay if possible. If the boat has a baby stay, tighten it to get some bend in the mast. That should take out some of the belly in the sail. Assuming it was in fact cut properly.
    At anything above 12 knots, it's time for outhaul tension and vang. Traveller should be dropped to leeward so that the mainsheet has some downward force on the boom.
    Play with shroud tension too. The leeward shroud on either tack should not be loose. If it is, the top of the mast could be bending too much to windward
    About 14 knots, a reef in the main might be in order.
    All of this would help, as well as getting crew weight up on the windward side. These boats are designed to sail flat and when they start heeling too much, they will tend to try to round up.
    A 110 jib isn't all that big, but rolling it in a little may help along wth getting the cars adjusted properly on the tracks.

    If you are new to the boat, you have to tinker with technique until you find what works for you. You will learn how your boat reacts and how it sails to suit you. Just have fun
     


  16. bgary

    bgary

    Joined Sep 17, 2015
    53 posts, 25 likes
    1985 Ericson 32-III
    US Everett
    How much is the boat heeling? Because the #1 reason for weather helm is heel. I would argue that - for the most part - the reason for depowering the sails (flattening, moving draft, etc) is to help the boat "stay on its feet".
    Before you start cutting on new sails, try an experiment - bring 6 of your best friends out for an afternoon sail and park them on the weather rail. See if that eases the weather helm (hint: it will)
    Assuming it does, the solution is to adjust sails (outhaul, luff-tension, mast bend, traveler, headsail lead-position, etc) - and techniques (steering with the inside telltale lifting, feathering in puffs) so that you can sail at an angle of heel that doesn't generate extreme weather helm.
    $.02
    Bruce
     


  17. Tim22

    Tim22

    Joined Jun 16, 2014
    167 posts, 14 likes
    Hunter 310
    CA Ottawa
    The boat does heel quite a lot. I have tried de powering by lowering the traveler and tightening the out haul which does help slightly. I will try adding a bit more bend in the mast and re check the shroud tension this weekend. I just wonder if the boat isn't just over powered with the current sail plan. I see on the Hyde web site the recommended main is only 277 sq ft which is roughly 10% less than my main.

    The Doyle rep will be joining me for a test sail next week so hopefully that will shed some light on the problem.

    Thanks
    Tim
     


    Last edited: Aug 5, 2016
  18. shemandr

    shemandr

    Joined Jan 1, 2006
    3,478 posts, 564 likes
    Marblehead Skiff 14'
    US Greenport, NY
    [The Doyle rep will be joining me for a test sail next week so hopefully that will shed some light on the problem. Thanks
    Tim/QUOTE]
    Excellent!
     


  19. Tim22

    Tim22

    Joined Jun 16, 2014
    167 posts, 14 likes
    Hunter 310
    CA Ottawa
    We were out today in 18 to 20 knots which didn't really allow us to try some of the suggested remedies as we were reefed - both main and jib. What I did notice was that when beating to windward the reverse diamond stays were slack. They tightened up again on the down wind run home. I'm not sure what this is indicative of, or what the the correct way to fix it is. suggestions?

    Thanks
    Tim
     


  20. JamesG161

    JamesG161

    Joined Feb 14, 2014
    2,896 posts, 838 likes
    Hunter 430
    US Waveland, MS
    Not good for mast stress. I think you found the first thing to fix.
    Jim...
     



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