Rawson 30 Pilot House Junk rig

  • 13 Dec 2016 00:41
    Reply # 4455956 on 4438217
    Deleted user

    The lady who will be putting the sail together studied fibers in uni, is a knotting, knitting, and sewing enthusiast. She showed me some of the stuff in her her dress making books and machine quilting books that make all of what I am proposing look simple. Neither of us have worked with a hot knife, but I was thinking if we fused a clean edge we would have less folding and stitching to worry about.

     If I intend to sew prestretched seatbelt material along both sides of the entire sail at the edge, and hand sew an outside boltrope do I have to worry about folding over the fabric for tabbing?

    The batten hinges are intriguing, but more work and money. Hopefully I can find 20ft battens to trim down. 

    I have been playing around with the graph paper (Danger!), If I went with batten hinges too, I would probably build it to the Mallory sail plan. I think the low yard angle is a good thing, but the mate does like the HM sail plan aesthetic, and Arne's method is pretty straight forward. Plus, his drawing just seems to suit our boat, why overcomplicate a good thing? 

    Although I do love wing sails, and their cousins (it is what drew me to junk rigs) this is no race boat. I am pretty confident I would be spending a lot more money on a rig that is more complex, and would probably still not really be the best choice for my type of boat and travel plans. 

    Alas, I am a tinkerer, and don't want my experimental tendencies to de-rail my budget, or suitability of the rig for hard, long distance travel. I like to push the boat hard, and she loves it. Nothing like sledding along feeling like you have the power of a freight train. I have a tendency to hold onto as much sail area as I can, so we have gotten quick at sail change and reefing. 

    10% seems like a good number if both Arne and David concur. Probably means I will have obstacles if I deviate and try and stack on more cloth. 

    My goal is to not need an engine, and I can sail without one just fine in all but the lightest of breezes, since I have a large sail inventory. If I am not totally happy with just the junk, I am sure I could make a light weight drifter with an amsteel luff to fly from a spare halyard and retractable bowsprit. 

    If we just go for sewn in camber, we will lay them out as illustrated in Arne's documents, but turn the panels into a 3d shapes by adding splits and broad seems at points a,b,c,d on adding cambered panels to Badger issue 50, p4. This method would be for 10% sewn in camber.

    If I have to join battens, I am really intrigued by the hinge and mild sewn camber  method. This course, I would go for 4-5% camber with just barrel cut panels, and make up the rest of the camber with the hinges to hit 10% I just think it would be really slick to watch an articulating sail as I plow along. Anyone on here have a lathe, willing to make the hinges or a plug for a reasonable price? I was reading on here about a fellow who has good luck with poured hinges. If I am forced to join battens, it would be nice to do it this way.

    More moving parts though, so naturally more things that can break. I imagine it a bit harder to fix a hinge or split batten at sea then sew in a patch or fix some stitching. 


    Last modified: 13 Dec 2016 00:57 | Deleted user
  • 12 Dec 2016 23:10
    Reply # 4455854 on 4455661
    Anonymous member (Administrator)
    Annie Hill wrote:
    James Hleba wrote:BTW, when is the next issue of the JRA magazine? I can hardly wait to see the details of Ingeborg's rigging. 
    February.

    nag, nag, nag  -  I haven't started it yet...

    BTW, the amateur method B may not look quite as posh as more elaborate methods, but it has proven to hold well. Besides, the method lets one replace a worn (or too small) batten pocket quite easily. No need to roll up and pass half of the sail under the arm of the sewing machine.

    The method started as a quick shortcut way of assembling an experimental sail (Malena, 1994), but when that sail finally fell apart after the 2010 season, the batten seams and boltropes were still good.

    Arne


    Last modified: 12 Dec 2016 23:29 | Anonymous member (Administrator)
  • 12 Dec 2016 20:46
    Reply # 4455661 on 4452740
    James Hleba wrote:BTW, when is the next issue of the JRA magazine? I can hardly wait to see the details of Ingeborg's rigging. 
    February.
  • 12 Dec 2016 20:44
    Reply # 4455656 on 4452740
    James Hleba wrote:

    Anyone know about hot knifes? How about this one?


    David is right that you can get away with normal sewing methods (I'd call them dressmakers' myself, but maybe David feels Canvas worker sounds more butch :-P!).  A flat-felled seam would do the job well, but does require more sewing.  However, at that price I'd go for (and will go for ) a hot knife.  You can always do both, but if you are unused to sewing, your edges may start to unravel if you have to undo a row of stitching.

    Having taken to my sample book of Weathermax with shears, I would say that it's not that prone to fraying, while you are working with it.  Similar to Sunbrella.  And of course you could always use pinking shears plus a flat-felled seam if you prefer.  Should you go for the latter, you are making a very strong seam so arguably, don't require to put in an extra row of stitching anyway. 

    One of the nice things about using soft fabrics such as Weathermax (and the late-lamented Odyssey II) is that you can use dress-making techniques.  Standard polyester sailcloth makes you understand why the phrase 'bending on the sails' is used and is quite unsuited to complex, folded seams and hems.

  • 12 Dec 2016 09:06
    Reply # 4453480 on 4452740
    James Hleba wrote:

    Anyone know about hot knifes? How about this one?

    We are considering using a sturdy inner and outer bolt rope, mainly because we appreciate the aesthetic, but may end up going for nylon strapping on both sides, plus an outer bolt rope to be sure the sail holds together when we need it most.

    David, Weaverbird seems awesome! 

    I like the idea of using hinged battens to add mild camber to the sewn in camber. I do not know much about what is required for hinged battens, as I have not thought too much about it. If I can not find 20ft lengths of tubing for battens, and will have to join sections any way. If this is the case, it would be nice to gain a little camber that way, and have less sewn in camber to worry about. What material would be acceptable to make the hinge? I am assuming the batten end would need to be sheathed to prevent splitting.

    I am having no luck finding "how to sew a tuck" or "tucked panel for Tom Thumb 24", I would just like to know my options of construction. It would be nice to aviod wrinkles if possible. (I found what I was looking for, JRA issue 50, Cambered Panels for badger, p4.)

    James,

    If you're really able to get Clipper Canvas delivered to Seattle, that would be the best, though Weathermax is now favoured by the professional sailmaker Sebastian Hentschel, I hear. 7.2oz US = 9 oz/sq yd, 150cm wide, and this is what you should use. Be aware that the next weight up is only 60cm wide, and so there's more sewing, with a need for an industrial-strength machine to handle it. You really shouldn't go that heavy. You don't need to hot knife if you use canvas-worker's methods rather than sailmaker's methods, turning in any cut edges. I did this on Weaverbird's sail, and can provide details, once the design and size of the sail has settled down. I would recommend just the normal sailmaker's tabling at the luff and leech. So long as the threadline is close to parallel to the edge, this is the best way. No need for bolt rope or webbing stitched on if you stick to standard sailmaking practice.

    10% camber is the maximum that you should aim for, and yes, I do prefer the mix of a little bit due to sewn-in shape, a little bit due to hinges. I used barrel cut, no tucks, because the amount of rounding was so small that tucks were both unnecessary and too small to make. I've put a drawing of the hinge in my top sheeted batten here , but you'll need to scale it up to your batten size. The ends of the tubes must be reinforced, and biaxial cloth and epoxy is probably the easiest way. I have two hinges in each batten except the top one, where there is one hinge. With each conical section being limited to 4 or 5 degrees of taper, there is no danger of levering the hinges apart. The forward part of the batten should have more length abaft the mast than forward of it, in the ratio 3:2, to ensure good articulation in light airs. Hinges at 30% and 55% of batten length is about right.

    You can find a drawing of a tuck and the Tom Thumb panel shape at 'Your files' in the menu/JRA Members Files /Drawings /David's doodles

    Last modified: 12 Dec 2016 09:11 | Anonymous member
  • 11 Dec 2016 20:24
    Reply # 4452740 on 4438217
    Deleted user

    Anyone know about hot knifes? How about this one?

    Fantastic, thanks Arne. We were trying to figure the rounding and such, and I think you are correct about 10% chord being a good number. The round starts to get unmanageable any larger based off some quick sketches I have done. We are considering trying to do the round and broad seam method to try and help with wrinkles, and it does not seem like too much extra work.

    We are considering using a sturdy inner and outer bolt rope, mainly because we appreciate the aesthetic, but may end up going for nylon strapping on both sides, plus an outer bolt rope to be sure the sail holds together when we need it most.

    We are going to build a scale model, and if we decide to shoot for more camber we will build a test panel out of cheaper fabric at full size. I suspect we will just stick around 10% camber, because it looks to be about the maximum the easy amature method B will easily support based off of my rough sketches. I don't want it to be too baggy and start snagging on things. I think we will be happy, long as I do not take too hard of a hit with my daily average. Over the course of 2000 nautical miles, I know the boat will reliably do around 100 miles over 24 hours, sometimes a bit more if conditions are perfect. I would like to try and retain that average. It just makes things easier as far as navigation goes. I love endurance sailing when we have a chance to escape for a few days, we cast off and sail hard around the clock exploring around islands until we have to head back to generate  funding for the conversion. 

    David, Weaverbird seems awesome! 

    I like the idea of using hinged battens to add mild camber to the sewn in camber. I do not know much about what is required for hinged battens, as I have not thought too much about it. If I can not find 20ft lengths of tubing for battens, and will have to join sections any way. If this is the case, it would be nice to gain a little camber that way, and have less sewn in camber to worry about. What material would be acceptable to make the hinge? I am assuming the batten end would need to be sheathed to prevent splitting.

    I am having no luck finding "how to sew a tuck" or "tucked panel for Tom Thumb 24", I would just like to know my options of construction. It would be nice to aviod wrinkles if possible. (I found what I was looking for, JRA issue 50, Cambered Panels for badger, p4.)

    BTW, when is the next issue of the JRA magazine? I can hardly wait to see the details of Ingeborg's rigging. 

    Last modified: 12 Dec 2016 06:35 | Deleted user
  • 11 Dec 2016 18:50
    Reply # 4452694 on 4452592
    Anonymous member (Administrator)
    Bryan Tuffnell wrote: Arne, do you use running lazyjacks with highly cambered sails? 

    Bryan,
    no, not on my boats (8% camber). I stress;
     I have no practical experience with 15% camber in junksails, only in the genoas of Bm rigs...

     

    One of the reasons why I make my sails with 10° rise on the boom, is that this gives plenty of clearance between any sprayhood/doghouse and the boom. I set up the standing lazyjacks a bit slack so as not to cut into the camber in light winds, with full sail set.

    As I reef, the clew of the boom drops quite a bit, but there is still clearance over that sprayhood. I cannot recall that I ever wished I had running lazy-jacks during a reefing operation.

    Arne



    Last modified: 12 Dec 2016 23:18 | Anonymous member (Administrator)
  • 11 Dec 2016 17:26
    Reply # 4452592 on 4452276
    Deleted user
    Arne Kverneland wrote:

    James,

    I have mentioned the use of up to 15% camber, but then I also wrote that a test panel should be made first, to ensure that it would actually work. I have not made cambered panels with more than 10% camber. 


    Arne, do you use running lazyjacks with highly cambered sails? 
  • 11 Dec 2016 11:49
    Reply # 4452276 on 4438217
    Anonymous member (Administrator)

    James,

    I have mentioned the use of up to 15% camber, but then I also wrote that a test panel should be made first, to ensure that it would actually work. I have not made cambered panels with more than 10% camber. My guess is that a panel with 15% camber would need to have broadseams added, as the rounded edge is now considerably longer than the straight line B.

    I think you would find a 50sqm sloop JR with 10% camber to be surprisingly powerful, and also close-winded. My guess is that it will easily outperform sister-boats with Bermuda rigs.
    I base this hunch on how my
    Johanna’s performance was boosted when she was upgraded to JR.

    Arne


  • 11 Dec 2016 03:26
    Reply # 4451979 on 4438217
    Deleted user

    I have some experience with clipper canvas, and rather liked the look and feel of it. I think we are going to end up going this route. It is a bit expensive, but I know I will have a serviceable sail for many years to come. I rather not mess around with untried fabrics. That being said, weathermax is locally available, and a smidge cheaper. I do know that a well cared for Clipper Canvas sail will last 10+ years, can be cleaned, retreated for UV protection, is a joy to work with and easy to patch. One of the Square riggers I have been on uses it. Great stuff.  

    I have still not decided on the weight. I like the idea of the light 7.2 oz fabric because I intend to use the baggy sails. I

    I think the  50 sqm meter rig should work. I will just increase the camber. I saw in one of your documents a suggestion of up to 15% camber, Arne. If I shoot for this, and pull the sail tight across the battens to minimize the wrinkles, I will probably be happy. It would also be nice to have a little tiny bit extra I can squeeze out of the rig by slackening the sail in a friendly competition setting. I would have the option of taking in sail too if need be. I figure it is easier to remove camber then add it in. 

     When I order I am thinking I should just get 70 sq m for a 50 sq m sail between waste, and other bits. I will find the precise area for all the pieces before I part with my dough. 


    Last modified: 11 Dec 2016 10:13 | Deleted user
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