From Gunter to Junk Main

  • 01 Oct 2022 11:10
    Reply # 12938700 on 12938663
    Anonymous wrote:

     I’m still flabbergasted by the cambered shape when the fanned sails twist. 

    It's a thing of beauty.

    What I'm not sure about, and maybe some people with experience could chime in here, is if the twisted fan sail doesn't have as good an angle of incidence into the wind as a sail with camber sewn in, and whether this matters anyway. The Westerly22 (with Mark I bilge keels) is so poor to windward that I can't really judge it. 

  • 01 Oct 2022 11:05
    Reply # 12938699 on 12938328
    Anonymous wrote:
    Anonymous wrote:
    See attached pictures. The sheet to batten 1 and batten 2 is a loop that passes through the cockpit coaming, so it can't run out and be lost. Likewise B3 and B4 form a loop. You can pull the loop and sheet two sheets at once. It's all very easy.

    Interesting, so you have  a sheet per batten it looks like, rather than a combining mechanism that pulls all battens with one sheet.
    Yes, exactly. It's workable at this scale but I imagine with a much bigger sail you'd need a 2:1 purchase on each sheet which might be just too much rope. With this particular sail you could even take all the batten sheets off if you were going for a lazy afternoon sail in light winds and just use the "conventional" main sheet on the boom and not have rope everywhere, especially with lots of guests on board. 
  • 01 Oct 2022 08:55
    Reply # 12938663 on 12925379

    Thank you for the extra information! That looks like a proper interesting layout. Especially in the precise amount of twist it lets you experiment with. I’m still flabbergasted by the cambered shape when the fanned sails twist. 

  • 30 Sep 2022 22:06
    Reply # 12938328 on 12937561
    Anonymous wrote:
    See attached pictures. The sheet to batten 1 and batten 2 is a loop that passes through the cockpit coaming, so it can't run out and be lost. Likewise B3 and B4 form a loop. You can pull the loop and sheet two sheets at once. It's all very easy.

    Interesting, so you have  a sheet per batten it looks like, rather than a combining mechanism that pulls all battens with one sheet.
  • 30 Sep 2022 12:23
    Reply # 12937561 on 12931657
    Anonymous wrote:

    Hi Jan,

    That looks like an absolute cracker! Glad it's working and that it's given you some cool projects for over the winter! Gives me some hope for my build...

    One quick question, do you have a sketch of your sheeting arrangement? Still undecided as to how I'll be sheeting Peggy and your method sounds to work well. I'm just struggling to picture the details haha.

    All the best,

    Zachary.

    Hi Zachary, this works better than expected but it is a small sail and easily manageable, 12 sq m. I'm not sure if it's transferable to a bigger sail but I don't think it has ended up being more faff or more spaghetti in the cockpit than any of the boats I had the pleasure of sailing on in Roscoff. 

    See attached pictures. The sheet to batten 1 and batten 2 is a loop that passes through the cockpit coaming, so it can't run out and be lost. Likewise B3 and B4 form a loop. You can pull the loop and sheet two sheets at once. It's all very easy. 

    The main sheet is a 2:1 purchase. In full sail the rig is operated much like any gaff/Bermudian sail, the boom and main sheet taking the loads. The batten sheets can then be adjusted to share the load on the sail or finely tune the fanned shape. I'm not getting enough twist yet as I have to move the mast sheave right up to the top of the mast. When reefed the batten sheets play their role in holding the reefed panel down and taking the load at the bottom of the sail. If you haul the boom right in amidships (by pulling on the sheets well over to windward) you can really feel the drive increasing. It seems to work a lot better on the port tack to windward.

    The arrangement at the stern will be replaced by a horse that will arch over the outboard well and will mean the sheets all go through from the centreline and won't need adjusting when we tack/gybe. The main sheet won't foul the tiller either, not that that is a problem now really. 

    One thing that I didn't foresee (but an expert would have guessed) is that the centre of effort of the whole sail-plan is lower than the original and so the boat hardly heels over... and then the bilge keels don't work (they're rubbish anyway) and we drift to leeward close-hauled , when I can get the whole sail higher it should help. If I have crew they can lean out to leeward in the complete opposite to most other boats.

    We've had a few more really nice trips and learn more each time. Just about finished now before winter sets in. 

    2 files
  • 25 Sep 2022 21:08
    Reply # 12931657 on 12925379

    Hi Jan,

    That looks like an absolute cracker! Glad it's working and that it's given you some cool projects for over the winter! Gives me some hope for my build...

    One quick question, do you have a sketch of your sheeting arrangement? Still undecided as to how I'll be sheeting Peggy and your method sounds to work well. I'm just struggling to picture the details haha.

    All the best,

    Zachary.

  • 20 Sep 2022 16:19
    Reply # 12925765 on 12925379

    Nice work, well done. 

  • 20 Sep 2022 10:19
    Message # 12925379

    I'm pleased to report that this armchair junkie has at last managed to convert our previously gunter rigged Westerly 22 Palinurus to a junk main. 

    It all started with Arne's article "From Gaff to Junk" and seemed to make sense for us to work with the original stayed mast and not embark on a costly full conversion involving a new mast in a forward position, the old boat (1963) is just not worth the effort involved. 

    The sail is a flat-cut, fanned type, derived somewhat from Vincent Reddish's mathematics but a slighter higher aspect ratio. It's on the small side, about the same area as the original Gunter with one reef in. So, it needs some wind to get going but is so much more well behaved in light airs than the old Gunter which had overly heavy spars which were frankly dangerous. With a bit of wind she goes well. Upwind performance is as terrible as I expected, especially in a lumpy sea. However, even though the baggy staysail is from the 1960's (a no.2 jib from a Falmouth quay punt) the whole rig is perfectly balanced and she will happily sail herself slightly upwind with the tiller free. Reefing is a doddle, as expected and the whole rig just feels safe and steady. Fabric is 175g/sqm Dimension Polyant Dacron sailcloth seconds. Battens are Spruce and are over-engineered at this stage but will be planed down to an optimum weight as I gain experience. 

    I have individual sheets to the boom and first four battens, actually an un-lose-able loop from B1 to B2 and from B3 to B4 passing through cam cleats. It works pretty well and allows full control of the sail shape. The YHP was the only other line I needed at this stage but I want running topping-lifts and tack-lines etc. With the staysail down she's a real pleasure to sail on a run with just the main but I'd like to be able to control the balance of the sail fore and aft of the mast. Suggestions are welcome but they are probably already on the to-do list. 

    I have to move the sheave further up the mast and place it at a diagonal. The top two panel leaches need re-sewing to stop flutter. All parrels and other control lines need optimising and a myriad of other little tweaks that I have identified after three trips out. And I'm working on designing a horse for the sheets and a hoop to keep them clear of the cockpit, nearly lost my sunhat a few times! Lots of work for the winter and a busy spring getting the whole boat shipshape and West Cork fashion in time for Morbihan...

    7 files
       " ...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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