Junk rig for Joe 17 trailer sailer

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  • 21 Feb 2017 15:11
    Reply # 4621175 on 4556642

    Phew! I just finished drawing and cutting the 1:1 panel models from a thick paper. 

    At the last moment I changed the plan from Arne's Johanna-type sail AR 2.10 to AR 2.15. I did this to get a bit shorter boom length (2980mm) in order to safely be able to use 6000mm aluminium tubes for battens. The sai area will be about 15,3 m2 compared to the 13,1 m2 of the bermudan rig.

  • 20 Feb 2017 11:08
    Reply # 4618830 on 4556642

    The fbaric for the sail has been ordered. I'll be using 92g ripstop polyester.

    I will also consider the possibility of using Roger Taylor hinge-system between the top three panels and the rest of the sail. This will make it possible to make the upper part of the sail from a thicker cloth later on, if needed.

    It's still February. The plan is to make the sail in the coming weeks and after that, if the weather permits (the boat is outside, and I have no indoor facilities for it) to start the mast and deck work. If all goes well, the boat should be ready for sail when the season starts here in the mid April or so.

  • 09 Feb 2017 17:15
    Reply # 4600685 on 4556642

    No, that wouldn't work, it's bending strength you're looking for, not compression strength. You need continuity from top to bottom. If you can get enough of the teak, you could scarph it to get the full length, but it seems to be making hard work of the job, when 30 x 100 pine (pinus silvestris) will do.

    From Oy Finnlumber Ltd:

    "Finnish sawn timber, based on a raw material grown in the Northern part of Europe, is known for its good quality and dense annual rings. Therefore the Finnish stress graded goods reach high strength classes and can be used in demanding end-uses."

    Last modified: 09 Feb 2017 17:54 | David
  • 09 Feb 2017 17:09
    Reply # 4600674 on 4556642

    Point taken, thanks.

    I might get my hands on 22x100 teak planks, but only at the length of 950 mm. Would it be enough with about 6300mm mast, if 600-700mm of the teak would be above the deck and the rest would go through it and be attached to a 100x100mm spruce "compression post"`that goes up to the deck level?

    Last modified: 09 Feb 2017 17:11 | Anonymous member
  • 09 Feb 2017 16:38
    Reply # 4600591 on 4599788
    Jami Jokinen wrote:

    I'm also fiddling around with the planning of the tabernacle. I was adviced using about 22x100 mm teak, which seems to be very hard to get.

    As an alternative, I was thinking about 30x100 mm birch-plywood (considerably stiffer than general plywood), cut in a way that gives the best vertical stiffness and which would be epoxied. Any thoughts?

    The horizontally grained plies would be doing nothing useful, just adding weight. Teak is not necessary, a local hardwood can be used. Is there any oak in Finland? Or other reasonably durable hardwood? If not, I would prefer slow-grown, close-grained softwood over plywood.
  • 09 Feb 2017 07:40
    Reply # 4599788 on 4556642

    I'm also fiddling around with the planning of the tabernacle. I was adviced using about 22x100 mm teak, which seems to be very hard to get.

    As an alternative, I was thinking about 30x100 mm birch-plywood (considerably stiffer than general plywood), cut in a way that gives the best vertical stiffness and which would be epoxied. Any thoughts?

    Last modified: 09 Feb 2017 07:41 | Anonymous member
  • 08 Feb 2017 13:20
    Reply # 4597525 on 4556642

    The mast issue is on it's way next. If I stick with my draft #2 (below), the mast should be around 6100-6300 mm above deck. The mast will probably be set on a tabernacle, unless I find it easy enough to step it without one easily enough every time (the boat is trailered to and from water on every sail).

    The aluminium tubes I can get my hands on here, are 6000 mm. I will probably go for a hybrid with a tapered wooden topmast, maybe 1500mmm or something like that. That would mean shortening the aluminium tube with maybe a 1000 mm.

    A 100mm/4mm tube is the obvious choice, I think. The 17 ft boat has a draught of 500kg and a ballast of 120kg - which I'm about to increase to maybe double of that. I think the hull shape has a significant role in the stability of the boat, because it is not easy to capsize it with the modest ballast and shallow keel. I like sailing in rough conditions and sometines quite choppy seas.

    I'm a bit worried about the weight of the mast, but I suppose 100mmm/3mm is not a safe option?

    Last modified: 08 Feb 2017 13:21 | Anonymous member
  • 07 Feb 2017 15:30
    Reply # 4595943 on 4595611
    Jami Jokinen wrote:

    Any caveats or design flaws you can spot, please?

    Looks good to me.
  • 07 Feb 2017 14:16
    Reply # 4595853 on 4595611
    Anonymous member (Administrator)
    Jami Jokinen wrote:


    The grey dot is the estimated center of effort of the BR. Arne's sail drawing is missing the central of effort, but I think it's right under the SA of the text "Total SA=...".

    The CE of my master sails sits about 1% of B forward of the middle, somewhere between batten 3 and 4.


  • 07 Feb 2017 10:00
    Reply # 4595611 on 4556642

    The BR and sails have been sold, so no turning back now :)

    I've been trying to balance with the SA and mast position (which seems to have only two possible places becaus of the structure of the boat). 

    The new draft has a SA of 15m2 compared to the 13,1m2 of the BR. I've used Arne's Johanna-style sail with a AR of 2.10. This makes the boom length of about 3000mm, which is nice, because the aluminium tubes available are 6000mm and the sailcloth width is 1700mm. The mast would be something round 6100-6200mm (EDIT: from top to the deck level!).

    Any caveats or design flaws you can spot, please?

    Draft#2 can be seen here.

    The grey dot is the estimated center of effort of the BR. Arne's sail drawing is missing the central of effort, but I think it's right under the SA of the text "Total SA=...".

    Last modified: 07 Feb 2017 11:15 | Anonymous member
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