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S2 6.7 Junk Rig Conversion

  • 02 Jan 2019 16:31
    Quote
    Reply # 6979991 on 6872873
    Anonymous member (Administrator)

    Scott

    That may work, but it surely would be a tight fit. It depends on how you fit the hoops along the luff and leech. Personally I prefer to make the battens a little longer (5-10cm?) than B. I then try my best to tie the after end of the batten flush with the leech, and then just let the forward end protrude from the luff. That makes it easy to tie the sail on and fit batten parrels, HK parrels and the block for the throat hauling parrel, THP (on batten 2).

    The forward end of the battens takes quite light loads. The quickest way of extending the 12’ tubes a bit, is probably to find a round stick of hardwood, say oak or ash, in a store, and then make suitable plugs from it.

    The other method presented itself for me in 2016 as I was making the battens for my Ingeborg: Due to a blunder, I shortened batten 6 instead of the boom. As the photo below shows, I mended it by fitting a splint type joint, using four strips of alloy, plus a number of pop rivets. If you could get an extra stub of that aluminium tube, you could easily add the necessary extra length of tube to each of them. However, I guess my Plan A would be the hardwood plugs, if I could find some of (nearly) the right size.

    Cheers, Arne

     
  • 02 Jan 2019 14:32
    Quote
    Reply # 6979773 on 6979606
    Anonymous member
    Anonymous wrote:

    Scott,

    My experience with my barrel-cut sails is that they never take up more length on the battens than the designed length, B. My last sail for my Ingeborg has B=4.90m. [...] the sail now only takes up 4.84m or thereabouts along the battens.

    This seems to be very good news for me. I was assuming that the battens needed to be longer than the designed 'B' on the sail plan for two reasons. The first is that PJR repeatedly stresses using the "fully stretched sail cloth" length. The second is that when I made my little Puddle Duck I cut the battens to be exactly 1.01B as in PJR and I found I needed much longer battens to stretch the sail. I ended up cutting some very long battens just to make it work. This was a flat sail with some very stretchy ripstop nylon for sail cloth.

    With your numbers I get the following:

    ((4.90 - 4.84) / 4.90) = 0.0122  (1.22% Shorter than designed B)

    With B=3700mm on the sailplan you drew for my boat and 12 ft (3657.6mm) battens I get this:

    ((3700 - 3657.6) / 3700) = 0.0115 (1.15% Shorter than designed B)

    This means it should be acceptable to use 12 ft long stock for battens on my B = 3700mm Arne-style sail?

    That would be very good news for my boat budget. I would prefer to use AL alloy for battens. I think I can do this if I buy 12 ft stock and use it directly.
  • 02 Jan 2019 13:42
    Quote
    Reply # 6979728 on 6979606
    Anonymous member
    Arne wrote:

    As the photo below shows, Ingeborg’s batten panels certainly take up a double-compound or 3-dimensional shape, so frankly, I fail to understand how those panels can be called ‘2D’.

    Arne


    Let me help you, Arne :-)

    Your panels will lay flat on the floor, either when first made, or when assembled into a sail: = 2D

    (but when the sail has been assembled onto a batten, with the wrinkles, puckering and gathering along the batten taking out some of the excess material, and then filled with wind: = 3D)

    A shelf footed, broadseamed or tucked panel will not lie flat on the floor either when first made, or when assembled into a sail: = 3D
  • 02 Jan 2019 10:50
    Quote
    Reply # 6979606 on 6872873
    Anonymous member (Administrator)

    Scott,

    My experience with my barrel-cut sails is that they never take up more length on the battens than the designed length, B. My last sail for my Ingeborg has B=4.90m. When fitted to the battens, even with no slack, it only took up 4.87m. After a few test-sails, I eased the tension about 3cm to increase the measured camber from 7% (of the chord) to 8%. In other words, the sail now only takes up 4.84m or thereabouts along the battens.

    As the photo below shows, Ingeborg’s batten panels certainly take up a double-compound or 3-dimensional shape, so frankly, I fail to understand how those panels can be called ‘2D’.

    Arne

     


    Last modified: 02 Jan 2019 10:51 | Anonymous member (Administrator)
  • 02 Jan 2019 08:55
    Quote
    Reply # 6979563 on 6978742
    Anonymous member
    Scott wrote:

    Looking back it might have been a good idea to design the rig around the 12 foot AL tube that is available. The next size up is 24 foot. I imagine for a 3700mm batten line on a sail plan I will really need about 14 feet (4267 mm) long battens.

    I don't understand this. If the batten line on the sailplan is 3700mm, then that's how long the battens are. On a 3D sail panel, the act of stitching generally causes the edge to shrink a bit so the battens don't need to be any longer than this; but on Arne's 2D barrel cut panels, the whole point is that the extra length of the curved edge is left as slack wrinkled cloth, so the batten length doesn't increase. I don't understand how the figure of 14ft arises.

    I think I have finally come to a decision after looking at a lot of fabric. Weathermax 65 seems like to way to go. It is more expensive than Odyssey but it certainly appears to have more actual fabric content at the same weight. I attached 'Weathermax65_Odyssey_Blue.jpg' which tells the story pretty clearly.

    Weathermax 65 looks much more convincing than Odyssey, but again, I suggest that you get a yard of it and do a sewing trial, to see whether it puckers like Weathermax 80, and in which direction.
  • 01 Jan 2019 17:14
    Quote
    Reply # 6978742 on 6977610
    Anonymous member
    Anonymous wrote:

    [...] LVL uses many thin laminations, and resorcinol glue, so should be very reliable.

    Thanks for the response. This was my thought when I looked at the LVL in person at the lumberyard. If two layers strengthen natural wood weaknesses then very many layers must be even more consistently strong. I will be keeping LVL in the back on my mind when it comes time to make spars.

    Looking back it might have been a good idea to design the rig around the 12 foot AL tube that is available. The next size up is 24 foot. I imagine for a 3700mm batten line on a sail plan I will really need about 14 feet (4267 mm) long battens.

    But I already made those paper patterns at 3700mm.

    Any advice for a first timer. Should I start over from scratch and make new patterns so I can use 12 foot stock AL tube? Should I add some wood to the 12 foot tubes like what was done on Footprints? LVL Spars?

    I think I have finally come to a decision after looking at a lot of fabric. Weathermax 65 seems like to way to go. It is more expensive than Odyssey but it certainly appears to have more actual fabric content at the same weight. I attached 'Weathermax65_Odyssey_Blue.jpg' which tells the story pretty clearly.


    1 file
    Last modified: 01 Jan 2019 23:18 | Anonymous member
  • 31 Dec 2018 09:17
    Quote
    Reply # 6977610 on 6872873
    Anonymous member

    I don't see any reason why LVL wouldn't make good spars. There's plenty of data in such sources as LP LVL Technical Guide if anyone wants to do some number crunching, but I see that the density is about 40lbs/cu ft, which is fine, and it must be a very consistent product, if they can quote strength figures for load bearing applications with confidence. If you were laminating yourself, you wouldn't go for more than two or three layers, but LVL uses many thin laminations, and resorcinol glue, so should be very reliable.
  • 31 Dec 2018 01:49
    Quote
    Reply # 6977352 on 6872873
    Anonymous member

    I have been wondering if anyone has experience or opinions on using LVL (Laminated Veneer Lumber) beams in making battens. I am considering using this as stock for wood battens to reduce the labor and make it easy to cut straight battens. Since the beams are already square, long enough and thick enough it should be just a few long rip cuts against the fence of a table saw to make battens.
  • 17 Dec 2018 22:01
    Quote
    Reply # 6963583 on 6872873
    Anonymous member

    Of those, I think I still prefer the POLYESTER_RIPSTOP_(DWR)-2.6_OZ  with its DWR treatment, which is not a coating in the sense that PU and PVC are. I wouldn't like a PU or PVC coating on a sail material that is going to flutter in the wind - All the cheap rainwear I've ever owned with PU coating, it's flaked off after a while.
  • 17 Dec 2018 20:55
    Quote
    Reply # 6963490 on 6962832
    Anonymous member
    Anonymous wrote:

    Now, are you going to reveal which cloths these are? I'm going to take a punt on the blue being Odyssey.

    Hi David,

    Thank you for taking the time to look. I was not trying to keep the fabrics a big secret. I named the files with something descriptive for each fabric. Now that I look at the posting I see that the file names are not really obvious unless you download the photos.

    I have updated the photos with the some descriptive text in the image itself. I also replaced the one that you said was too bright with a clearer version. On top of that I got two more small samples in the mail today. I took more photos of those two. The whole mess is now in my member photo album. I will add descriptive links below.

    Your kick (gamble?) was good. The blue stuff is Odyssey.

    1.6_HyperD_PU4000

    (ripstopbytheroll.com)

    1.9_Ounce_IMPORTED_Polyurethane_Coated_Ripstop

    (www.seattlefabrics.com)

    2.2_Hex70_PU3000

    (ripstopbytheroll.com)

    Odyssey_01

    Odyssey_02

    POLYESTER_RIPSTOP_(DWR)-2.6_OZ 

    (www.fabricwholesaledirect.com)

    Red_210_Denier_Coated_Nylon

    (www.onlinefabricstore.net)

    Red_600_300_Denier_PVC_Coated

    (www.onlinefabricstore.net)

    Scott

    Last modified: 17 Dec 2018 21:26 | Anonymous member
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