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Freedom 40 Cat Ketch Junk Rig Conversion

  • 23 Jan 2017 03:19
    Quote
    Reply # 4562774 on 1424184
    Anonymous member

    I would gladly add these and future files to the"Box".  I have an account under bad.wabbit@gmail.com if somebody could give me proper access JRA folder.  At present I can only view the folders.


    Erik
  • 22 Jan 2017 23:05
    Quote
    Reply # 4562561 on 1424184
    Anonymous member

    hi annie

    i see why it's better to store the files 'on site', and i do this for my stuff. but as the files are not from me, i won't upload them anywhere.

    i just said that there's no need for an own account to download files from a dropbox – even if it looks so…

    ueli
  • 22 Jan 2017 19:51
    Quote
    Reply # 4562336 on 4562174
    Anonymous member
    ueli lüthi wrote:
    David Tyler wrote:
    Please could you put the dxf files into our Box folders, 'your files' in the Members' Area, so that I don't have to open a Dropbox account?
    you don't have to open an account – just close this window…

    …but it's annoying…

    Ueli: if you could use our Box folders, this would mean that other people following this thread now and in the future, can also take advantage of these files.  In another year, we may have a new member with a Freedom 40 they want to change to junk rig, and it will save everyone from having to do the work all over again.  Not everyone can access your Dropbox account and theres always a chance you might close it, anyway.  All members can use our Box folders in Your Files in the Members' Area.

    Annie (posting as me, but really wearing my Chairman's hat).
  • 22 Jan 2017 17:25
    Quote
    Reply # 4562174 on 4561642
    Anonymous member
    David Tyler wrote:
    Please could you put the dxf files into our Box folders, 'your files' in the Members' Area, so that I don't have to open a Dropbox account?
    you don't have to open an account – just close this window…

    …but it's annoying…
  • 22 Jan 2017 09:52
    Quote
    Reply # 4561642 on 4561519
    Anonymous member

     If I draw a 10 deg line upward from the most aft location on deck that would not interfere with a dodger over the hatch ...  

    12 deg batten angle - OK, but would it also be required if I opt for hinged battens?   

    Arne - we currently have (too much) weather helm, so I'm OK with the CE moving forward.  I just don't know if 30 cm or 60 cm is a small amount or a lot.

    DropBox links below for the current designs.  I will play around some more with the suggestions to see what things look like.

    70 deg Yard

    40 deg Yard

     

    Erik

    I see what you mean about the clash between the foresheet and the dodger over the main hatch. Would a strong hoop over the dodger to carry the sheet blocks solve the problem?

    I have a batten angle of 11 degrees, and this is about right for my hinged battens + a little barrel camber.

    A schooner rig on a long keeled hull shape is not very demanding as to theoretical CE position. Though 60cm, 5.6% of LWL, does sound rather a lot.

    Please could you put the dxf files into our Box folders, 'your files' in the Members' Area, so that I don't have to open a Dropbox account?
  • 22 Jan 2017 06:33
    Quote
    Reply # 4561519 on 1424184
    Anonymous member

    David/Arne thank you both for your input and votes for the sail shape.  I feel like justice would only be served to do one of each :)  

    More seriously:  

    Yard length and resulting weight:  Comments much appreciated.  If I understand the geometry correctly, a larger yard angle results in a longer yard.  So maybe in this instance less/lighter is better.  I am guestimating at ~ 40 degrees, but it is partially optics and what may still work with the topping lifts.  

    Sail size:  I think I have some constraints regarding the size sails I can fit so I'm not sure I can follow all of David's advice.  I think the room between the fore and aft mast is the limiting factor.  If I draw a 10 deg line upward from the most aft location on deck that would not interfere with a dodger over the hatch - that is 4980 mm from the center line of the fore mast - then 15% sail overlap gives me nominally a +/- 4300 mm batten length about 8100 mm off the deck.  Other factor in play are that I would like the clew to be no more that 1600 to 1800 from the deck so I can reach it, and the tack 800 to 1000 mm  so it clears the bow pulpit.  This kinda creates the bottom of a box that then dependis on a reasonable aspect ratio. 

    I do have this idea that a flexible "wand" similar as is used on a backstay to hold it away from a large roach on a main, may work on a short 5th batten.  This wand would hold the slack sheetlet away from the luff when tacking and jybing, yet bend and provide the correct sheeting angle when the sheet is tensioned.  

    12 deg batten angle - OK, but would it also be required if I opt for hinged battens?   

    Arne - we currently have (too much) weather helm, so I'm OK with the CE moving forward.  I just don't know if 30 cm or 60 cm is a small amount or a lot.

    DropBox links below for the current designs.  I will play around some more with the suggestions to see what things look like.

    70 deg Yard

    40 deg Yard

     

    Erik
  • 21 Jan 2017 10:46
    Quote
    Reply # 4560485 on 1424184
    Anonymous member (Administrator)

    You know, I generally would suggest the Johanna-style rig for most boats. However, on large and really high-AR sails used on schooners, I think the Weaverbird-style planform may be more useful: One saves weight of the yard, and there is probably lighter trimming forces on that yard as well (YHP, THP). In addition, the Freedom 40 already has as tall masts as one can ask for, so that is no problem.

    Can I ask, how does your Freedom 40 balance under the original rig? This would have influence on the position of the CE of your JR.

    Arne
  • 21 Jan 2017 08:21
    Quote
    Reply # 4560398 on 1424184
    Anonymous member

    I think what I'd try is to adopt the weaverbird shape (well, I would say that, wouldn't I?), as in the second drawing of equal sized sails, increase the batten angle to 12 degrees (to allow for building in camber), scale it up to, say, 48 - 50 sq m for each sail - and then take the bottom panel off the foresail to bring the CE back nearer to where it is with the current rig.
  • 20 Jan 2017 22:49
    Quote
    Reply # 4559874 on 4559729
    Anonymous member
    Annie Hill wrote:

    there is little gear or tankage (200 gal water, 100 gal diesel when filled)


    Blimey!  What do you call generous tankage??

    Wasn't me that designed that.  There is a BIG note in the log book from the original owner not to fill the diesel tank near the end (East Coast) sailing season.
  • 20 Jan 2017 21:00
    Quote
    Reply # 4559729 on 1424184
    Anonymous member

    there is little gear or tankage (200 gal water, 100 gal diesel when filled)


    Blimey!  What do you call generous tankage??
       " ...there is nothing - absolutely nothing - half so much worth doing as simply messing about in junk-rigged boats" 
                                                               - the Chinese Water Rat

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