Generic "Fantail" sail planform drawing

  • 21 Dec 2012 00:35
    Reply # 1164353 on 1060993
    This is a fascinating thread.  I have indeed missed a great deal in my absence.
    I have recently been pondering going with a Fantail sail on Seablossom rather than the Arne sail I had originally intended to make for her, and this discussion and your recent work, David, convince me that I should do exactly that.
    For the short term I have misplaced the sail plan that Paul drew for me.  I was working by memory when I put the new partners in the foredeck.  I'll need to do some research to see what size sail I will be making, and then might try to impose upon you to work up the dimensions I would need.
  • 19 Sep 2012 06:20
    Reply # 1076216 on 1060993
    This is where it's at! Thank you, David!

    Thank you, Karlis for making the work even more accessible!

    Cheers,
    Kurt
  • 07 Sep 2012 21:16
    Reply # 1066940 on 1060993
    Oh, thanks for noticing that! The original scaling values in there for the mast are based on a spreadsheet for Arne's Johanna rig.  I'm not sure how appropriate they would be for fantail at any scale, that's why I wanted to know your mast height scaling factor. Minumum bury is based 10% of length at partners.

    You've got a point about making it too easy. Making the spreadsheet was my way to get cozy with the numbers and the plan, and in doing so I noticed much I didn't at first. Still, once you get on to measurements and layouts on the cloth, there's no easy way and you'll quickly get pretty initmate with those numbers. I definitely found the spreadsheet helpful when I was experimenting with sailplan ideas and comparing values for mast dimensions and sail areas.
    Last modified: 07 Sep 2012 21:17 | Anonymous member
  • 07 Sep 2012 06:31
    Reply # 1066450 on 1060993
    Karlis, 
    Thanks for doing that. I've uploaded these two spreadsheets into the same folder as the drawing.

    I think there may be a danger in making things too easy - following a recipe blindly and without understanding is not usually a good thing to do - but these spreadsheets may avoid finger trouble on the calculator.

    BTW, I found an error in cell B29, for the mast calculation, and have uploaded corrected versions. The sail calculations are OK, I think.
    Last modified: 07 Sep 2012 20:51 | Anonymous member
  • 07 Sep 2012 02:25
    Reply # 1066266 on 1060993
    David, I've been looking at your sailplan in PDF format.  I've created a spreadsheet to do all the calculations required, and in doing so I came up with some suggestions.

    • All measurements should be uniquely labeled, for example L1-7,B1-9,P1-8, D1-5, etc. This way each measurements can be referred to unambigously ("I reduced the batten length at B9 . . . ").
    • Since you're using colour in your diagram, you should use a different colour for each set of measurements (battens, luff rise, leech, luff rounding, diagonals). 
    • include sail CE, and sail panel areas.
    • Include recommended mast height.  This could also include a recommended sail positioning from the luff, and recommended minimum distance aft of leech for sheeting.

    Well, maybe you don't want to make it too easy, but with the first two items for clarity and the second two for completeness, using the sailplan and the spreadsheet it will be quick to incorporate this info into a potential design sailplan.  

    I guess I can't include a spreadsheet file here, I can email it to you.
  • 06 Sep 2012 01:47
    Reply # 1065479 on 1063968
    Annie Hill wrote:I have been unhappy with the way my boom was positioned and a crease that kept appearing in panel 5 (from the top).  I am still experimenting here and feel that I am going to be shot down in flames, but I have reverted to hauling the forward end of the boom into the mast with a standing boom parrel.  In addition, I have added a standing luff parrel from boom to batten 7 and between battens 5 and 6.  These are now hauling the luff back to where I want it to be whether the sail is set fully or reefed and also seem to be reducing the loading on the luff hauling parrel. 

    Very interesting, Annie.  Blondie used a standing luff parrel on Pilmer, first setting up a temporary standing boom parrel to haul the boom into the desired position then setting up the luff parrel.  He then dispensed with the boom parrel.  When he dropped the first panel the boom moved a little forward until the now horizontal luff parrel took up the role of a boom parrel.  He felt that moving the sail a bit forward when reefed was beneficial to balance but of course his sail was flat and our cambered sails are different beasts and it may be that you need both to control your creases.

    I did fit a couple of standing luff parrels to Arion last year, from the boom to the lowest batten and then another one from that batten to the batten above.  I found, with the way my battens want to go forward so aggressively, that it caused a lot of friction when lowering the sail but they worked well otherwise.  It is always fascinating to hear of the various experiments going on in the hunt for the perfect arrangement.  My set up is still far from perfect and I am looking closely at Arne's ideas at the moment as he seems to have got his HM sail working well.  I might try a Fantail sail one day when I have money and energy to spare.
  • 04 Sep 2012 12:00
    Reply # 1063968 on 1060993
    I have been unhappy with the way my boom was positioned and a crease that kept appearing in panel 5 (from the top).  I am still experimenting here and feel that I am going to be shot down in flames, but I have reverted to hauling the forward end of the boom into the mast with a standing boom parrel.  In addition, I have added a standing luff parrel from boom to batten 7 and between battens 5 and 6.  These are now hauling the luff back to where I want it to be whether the sail is set fully or reefed and also seem to be reducing the loading on the luff hauling parrel. 

    I have not done much sailing recently - winter weather and other distractions - so it's early days.  When I make the new yard, I plan to use rope rather than hardware.  Kurt has promised to help and his input will be much appreciated as to the different tweaks.  But I am delighted with the difference the standing luff parrels have made to the lower part of the sail, particularly in a sloppy seaway.  They don't put any stress on the battens, unlike my personal experience with Hong Kong parrels.
  • 01 Sep 2012 09:06
    Reply # 1062168 on 1061901
    Anonymous member (Administrator)
    David Tyler wrote:
    Arne Kverneland wrote:  My experience with this is that the throat and yard parrels definitely offload the HK parrels with 90%+, but the HK parrels are still useful in stabilising the luff as the boats (Johanna or Edmond D) are pitching against a headsea. From the photo of that F7 testsail of Ti Gitu it appears that they were sailing on flat water and I fear that the battens 4-5 may well start sliding back and forth in a seaway, but I could well be wrong here as the sheets may keep the panels steady.

    Arne

    Arne, 
    This could be a significant point of difference between the behaviour of a long-luff, parallel-batten sail, and a short-luff, fanned batten sail. I notice no tendency for the lower battens to slide fore and aft in a seaway.


    I agree. Ti Gitu's tall sails are quite different animals from Tystie's low AR sail. Even the two sails of my boats; Broremann's with AR=2.15 and Johanna's with AR=1.87 behave differently.

    Arne

  • 31 Aug 2012 23:24
    Reply # 1061901 on 1061878
    Arne Kverneland wrote:  My experience with this is that the throat and yard parrels definitely offload the HK parrels with 90%+, but the HK parrels are still useful in stabilising the luff as the boats (Johanna or Edmond D) are pitching against a headsea. From the photo of that F7 testsail of Ti Gitu it appears that they were sailing on flat water and I fear that the battens 4-5 may well start sliding back and forth in a seaway, but I could well be wrong here as the sheets may keep the panels steady.

    Arne

    Arne, 
    This could be a significant point of difference between the behaviour of a long-luff, parallel-batten sail, and a short-luff, fanned batten sail. I notice no tendency for the lower battens to slide fore and aft in a seaway.
  • 31 Aug 2012 22:52
    Reply # 1061878 on 1060993
    Anonymous member (Administrator)

                                                            Stavanger, still Friday, just

                                     Paul Fay about Ti Gitu

    Paul Fay’s article was very interesting. His finding that it paid to shorten the boom (and in his case also the lowest batten as well) and also his conclusion that the correct use of a throat hauling parrel and yard hauling parrel is Step Number One to get the sail to set right, confirms my own findings here. I also notice that he now has tested the sail successfully without HK parrels thanks to the use of the two "top" parrels. My experience with this is that the throat and yard parrels definitely offload the HK parrels with 90%+, but the HK parrels are still useful in stabilising the luff as the boats (Johanna or Edmond D) are pitching against a headsea. From the photo of that F7 testsail of Ti Gitu it appears that they were sailing on flat water and I fear that the battens 4-5 may well start sliding back and forth in a seaway, but I could well be wrong here as the sheets may keep the panels steady.

    Arne

    Last modified: 31 Aug 2012 22:56 | Anonymous member (Administrator)
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