Conversion Westerly 22

  • 06 Jun 2018 21:45
    Reply # 6291335 on 6285145

    I think you will be OK with 130 - 150mm luff length.

    The way to increase positive stagger is to increase the batten angle relative to the horizontal. You have designed an angle of 8 degrees, which is quite low. When you build camber into a sail, there is a need to increase the batten angle, to compensate for the extra length of the diagonal due to the extra cloth. I should use an angle of at least 10, maybe 11 degrees. 

    Have you considered using Arne's transitional panel, increasing the angle of the top sheeted batten so that the top triangles get smaller? I think you would find this worthwhile. Have a look through Arne's sailplans, and compare them with what you have drawn. Their proportions have now been well proven.

    The lead should generally be around 9% of waterline length, for cambered sails, but this is a very inexact science.

  • 06 Jun 2018 20:43
    Reply # 6291024 on 6288016
    David Tyler wrote:

    Frank, the only things that I can see are that, depending on how you make the pockets, you might find that your luff length of 100mm for the top panels is too small for comfort, and it might be difficult to squeeze everything in without too much overlap. If the battens are overlong, they will clash. Also, the batten stagger on the lower panels is neutral, neither positive nor negative, which is OK, so long as you are aware of it and are sheeting a long way aft. Otherwise it looks fine.

    Thank you for you answer David! Do you think a luff length of 200mm would be enough or is this already to long? Regarding this PJR recommends for example ~130mm.

    I wasn't aware of the problem with the batten stagger, thanks for pointing that out! I hope that it will work that way. It appears to me without further research that we still might have the option to make the upper battens longer or the lower panels shorter in case it wouldn't, no?

    PJR recommends the CE for the single masted CE 6% of the WL abaft compared to BR one. Is this still the value most people calculate with or are there other experiences over the time?



  • 06 Jun 2018 09:20
    Reply # 6288016 on 6285145

    Frank, the only things that I can see are that, depending on how you make the pockets, you might find that your luff length of 100mm for the top panels is too small for comfort, and it might be difficult to squeeze everything in without too much overlap. If the battens are overlong, they will clash. Also, the batten stagger on the lower panels is neutral, neither positive nor negative, which is OK, so long as you are aware of it and are sheeting a long way aft. Otherwise it looks fine.

    Last modified: 06 Jun 2018 09:37 | Anonymous member
  • 05 Jun 2018 21:00
    Reply # 6286852 on 6285145

    Ups I just saw that you can hardly see the first one but there are 2 files, it is actually right in front of the other one.

    Frank

  • 04 Jun 2018 21:29
    Message # 6285145

    We are up to convert our W22. With the help of Practical JR (what a awesome book!) we designed the sailplan as good as we can. If someone with more experience in the construction of sailplans could have a look over the plan and save us from mistakes we would be very happy and thankfull. Our main goal was to keep the hatch and position the mast in front of it like it is in similar boots (Kingfisher26 for example). 

    We measured a waterline of 5930mm the official one is 5590mm. The new CE is roughly about 6% abaft the old one. The total sail area would increase from the old 21.09m² to 23.88m² which is ~13% more. The mast lengh above deck is 7840mm + under deck ~1220mm makes in total 9060mm. Which seems alright compared to the mast database. 16% of the total mast length would be under deck. The drawings are attached and we could also provide the Sailcut8 and/or CAD files.



    Last modified: 04 Jun 2018 21:35 | Anonymous member
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