Rawson 30 Pilot House Junk rig

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  • 14 Dec 2016 23:45
    Reply # 4460493 on 4438217
    Deleted user

    I was playing with a thin cardboard version of the sail I drew, and agree that it probably will not work.

    I made a small model with strings and dowel, and it just really does not set well, and is snagging. 

    Yup, I am just going to follow Arne's system since it has been proven to work with good results multiple times, and has loads of documentation for if I get stuck in a spot.

    The only thing I may deviate slightly is how the panels are sewn together. I plan to use the clipper canvas, so I will probably add broadseam to help prevent wrinkles. I plan to spend a lot of time staring at this sail, so I am not opposed spending a bit of extra time on construction to try and make it as nice as I can. 

    Thank you for all the help, and the great information! I figure I won't know what I like or don't like about any rig until I have several hundred miles at least under the keel. I am confident I will be happy with the results from this route.  

  • 14 Dec 2016 18:04
    Reply # 4459377 on 4458423
    James Hleba wrote:

    ps: Here is a sketch of the sail from cad. The mast may not be quite in the right location, but you get the point. 575 ft sq of sail area, but not as pretty.

    This link doesn't work, James. You need to go to your directory profile (click on "View profile" and then "My directory profile", to copy the URL to make a link. Check that the URL has "PublicProfile" in it.
  • 14 Dec 2016 17:58
    Reply # 4459357 on 4459251
    Arne Kverneland wrote:

    Now I found your proposed sail in your album. I don’t think it will work. The angle of the halyard to the slingpoint on the yard is way too flat.  I suggest, if this is your first JR, that you copy some rig that is known to work, made for instance by Paul, David, Slieve or myself. That reduces the likelihood of real screw-ups.


    I echo that. I have to say that your drawing, James, contains a number of errors.

    Your first attempt at designing a junk rig ought not to try to break new ground. It's worth rubbing it in:

    For your first junk rig, copy a rig that has been designed for the type of sailing that you want to do, and proven itself to be suitable and successful. 

  • 14 Dec 2016 16:52
    Reply # 4459251 on 4438217
    Anonymous member (Administrator)

    To CAD or not to CAD

    Paul’s saying that one can get “ a firm grasp of” the QCAD after one weekend of studies, is a bit optimistic. Maybe I am a bit thick, I don’t know. I had to have 2-3 real goes at it before it started to make sense, and I would say that it was a real time thief until then. Only when I started designing the ten master sails, did the QCAD program really pay back, and from then on it has been easy.

    I suggest that if you go for the sail I drew up for you (50sqm, AR=2.10), you skip any CAD programs and just grab that master sail with AR= 2.10 from my library, and print out the two sheets of it. Then you bring out a calculator and scale up all the dimensions of the master sail. That should take you no more than one hour.

    My idea with those master sails is to shorten the time between head-scratching and beginning to cut in canvas.

    Now I found your proposed sail in your album. I don’t think it will work. The angle of the halyard to the slingpoint on the yard is way too flat.  I suggest, if this is your first JR, that you copy some rig that is known to work, made for instance by Paul, David, Slieve or myself. That reduces the likelihood of real screw-ups.



  • 14 Dec 2016 02:33
    Reply # 4458423 on 4438217
    Deleted user

    Thanks for all the tips! I will look into qcad, but I have a free demo of turbocad for the next 30 days, I feel the skills probably translate across a bit. Q cad is way cheaper, so I might have to purchase it, and force myself to learn it. 

    David, I have heard great things about the winches you posted. I already own 2 lewmar 42, two speed winches in great shape. I plan to just use them for halyards, or drogue, anchor, crab pot, ect retrieval. For the price, and if I can find gray, I will try out a set a of the barton "wincher". They are close to the bottom of the page. I think practical sailor wrote about them. People that have them seem to be happy if they are smarter than the rubber ring and figure out how to install them. I know I do not have the budget for more winches, especially since I have 3 really nice ones, but if the $50 a set rings will help me snub I will be happy. I always cleat off even when using self tailers, old habits die hard. 

    I think weaverbird's mast placement is smack in the middle of the berth, makes cuddling a bit hard. So that's out unfortunately. I like the mast position of arnes from an interior space perspective, plus I will not have any interference of the coach roof and partners reinforcement. The plan I drew up I think lands between the Weaverbird and HM rig. I have to verify, my numbers again.

    It is looking like the rig Arne drew up will most likely be the victor because it just seems to work with the boat. Also, I like the single sheeting better than the double sheeting, which I suspect the planform I drew would probably need. I guess it comes down to what the actual math reveals, and if I rather deal with whatever rigging obstacles to gain a bit more sail area... It is an illness I am convinced. Had a bad cylinder on my baja bug, when I was finished it was a turbo charged 1888 cc stroker. I need to avoid such a scenario with this vessel. If I needed a fast sail boat, I would have bought a cat or tri, and put a wing on it. I just need to focus on trying to keep similar performance I have now, minus the downwind parachute I have been experimenting with.  

    ps: Here is a sketch of the sail from cad. The mast may not be quite in the right location, but you get the point. 575 ft sq of sail area, but not as pretty.

    Last modified: 14 Dec 2016 12:58 | Deleted user
  • 14 Dec 2016 01:14
    Reply # 4458354 on 4438217

    Hi James, Arne, David & myself all use QCad Professional for our CAD work. It's not expensive, does the needed and is relatively easy to use. If you also get the  QCad Book you will be up to speed and using it in no time at all. If you spend a weekend working through the book and the exercises you will have a firm grasp of CAD principals and a good understanding of QCad. Very shortly there after you will be wondering why it took you so long to learn CAD drafting... It saves so much time.

  • 13 Dec 2016 23:17
    Reply # 4458282 on 4438217
    Deleted user

    Thanks! Looks good. I have drawn up a bunch of sails using graph paper, and have got one planform that works nicely. I do not know cad, and I am trying to learn, so I am doing a lot of face palm bashing trying to import an image, make the lines at proper angles ect. I am trying turbocad now, but will probably give up because it is taking me too long to achieve nothing at all with it. 

    Drafting is so much easier for little one off projects. 

    If I can't get trubocad figured out, I will just scan in the sail.

    It is a Mallory variation that has 6 lower equal panels, the batten/ boom angle is 80 degrees from leach to foot. Batten length is 18ft 6 in. 2 top panels in the typical Mallory fashion. The sail is quite similar to what Arne presented, minus the top panel, and adding a bottom one. Sail area with this set up is 575 ft sq. 

    I need to get some more thin cardboard to glue it to get a more accurate balance point.

    I have decided against hinged battens entirely. I had a dream last night I was sailing along with a hinged batten setup, and we were surprised by a gust out of seemingly nowhere, resulting in a powerful knock down, a couple shattered hinges, and split and blown out battens. Seems good enough reason to me to avoid hinges and stick with solid battens. 

    Happy sailing, and thanks for all the design help. You know what they say, a carpenter is just a frustrated architect. :p Excited for when I get to the actual building, that is my strong suit. Still waiting on payment for some work I did that should cover the cost of most, if not the entire conversion. Running a business, trying to make profit, and actually collecting the due payment can be a smidge tricky at times. 

    Last modified: 14 Dec 2016 00:49 | Deleted user
  • 13 Dec 2016 11:39
    Reply # 4457119 on 4438217

    Thanks for helping me out, there, Arne. I still can't get the hull image to display on a PDF export. 

    Yes, I think the weaverbird planform will work here, so long as the mast position fits in with the accommodation. The partners need to go right at the forward end of the coachroof, further back than your planform.

    The mast length of 44ft is just enough, if the heel of the mast is at the waterline. The sail might be raised a bit higher, and the halyard drift reduced, if the halyard is rigged as I prefer, with two single blocks at the masthead, and a single and becket on the yard, giving a 3:1 purchase. A self tailing winch then makes up the required power. I used, and recommend, an ARCO 30:1 / 14:1 two speed self tailer for this size of sail.

    I would need to adjust the sail to add a batten. Weaverbird only needs five sheeted battens, but this sail will need six sheeted battens. Separate upper and lower sheets are highly desirable to control twist.

    The batten length is 5.11m, and the yard length is 3.79m, with a lightweight extension ft to ensure that it stays the right side of the topping lifts.

    I would strongly recommend that the cloths are laid parallel to the leech. The sail is 5m wide, so using 1.524m wide fabric, 3 1/2 cloths are needed. This puts the seams just where they are needed to add broad seam at the forward two seams ( no broad seam at the aftermost seam, to keep the sail flat here). I would draw out the panel shapes needed for this method of working. The tablings would be 60mm wide, turned in twice, so an extra 120mm of cloth needed at both luff and leech. NB no webbing required, and certainly no hand-sewn bolt rope - we're in the 21st century now! It wouldn't help with the real-life issues that a junk sail faces. For long-term, ocean-going use, a doubler, 300mm wide, is added along the leech before the tabling is turned and sewn. This adds weight and stiffness to prevent flutter and cloth breakdown. Another doubler might be added in way of the mast on the lower three panels, as the pinching that occurs between battens and mast when reefed is another cause of damage.

  • 13 Dec 2016 09:56
    Reply # 4456954 on 4438217
    Anonymous member (Administrator)


    David sent me a 50 sqm version of his Weaverbird rig. Since we both use the same CAD program, it was easy for me to install the sail on that Rawson 30. I found the drawn in CE ("CE1") to be further forward than CE2 which I found by balancing the sail on a ruler. I use CE2 to position the sail with the CE in the same place as the CE of the Bm rig. See for yourself. I think it looks good

    Note; the sails may need to be raised a bit more to clear your wheelhouse.


    Last modified: 13 Dec 2016 11:57 | Anonymous member (Administrator)
  • 13 Dec 2016 02:55
    Reply # 4456454 on 4438217
    Deleted user

    Finally found the "your files" along with all the amazing member perks! Wow, looking at the weaverbird plan has me thinking again. Correct me if I am wrong, but this setup would shift my mast back a bit right? Hmm.... How tall of a mast was projected for the cornish crabber 30?  

    Everything on this site is so inspiring! 

    Fighting with sketchup trying to load the weaverbird .dxf. Hmmm seems sketchup for chromebook does not allow you to open files outside the native ecosystem... that's silly. 

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