A new rig for Leeway

  • 23 Jul 2016 08:54
    Reply # 4151904 on 4138614
    Anonymous member (Administrator)

    This is getting interesting

    Batten stagger

    First of all, Hong Kong parrels have nothing to do with batten stagger when reefing. They go slack the moment the panel starts to collapse. I rely on half-short batten parrels to get a tidy enough sail bundle. With the depth of camber I use, it is not enough with 10° batten rise to get a natural positive batten stagger.

    On my present boat, Ingeborg, I now set the sail in the fore position to remove some weather helm. That works well, and it is actually easier to set the sail like that than in a hauled aft position (I had developed a habit of hauling the sail aft on my Johanna to avoid lee helm).

    A bonus with Ingeborg’s sail is that when I reef, the sail doesn’t move forward as the first panel is lowered. On the last four junksails I have shortened the boom about 4% at the clew, to compensate for this forward movement, i.e. negative stagger. Now, on Ingeborg that is no longer necessary, but her shortened boom does no harm either.

    I suggest you have a close look at how Paul Fay has made the tall schooner rig of his Ti Gitu work. He uses some sort of fixed parrels which sort out any stagger problems when reefing. I bet he has some useful advices on this.

    Sheeting, single or double.

    I have seen the double sheeting in use on the 23ton schooner Samson. It appears to be easy and quick enough to use and keep tidy (reels help a lot). In light winds, the skipper hauls on both sheets in one grip. As the wind picks up, he hauls on one end at the time. The positive twist control (read: avoiding excessive twist when reefed) is a big bonus with double sheeting, and is probably even more useful when the sheeting angle is quite steep, as on tall two-sail rigs.

    Boom rise

    I have been using 10° rise as a standard, after the first sail on Malena came with 5° rise.  The increased rise ensures better view to leeward when beam-reaching in some wind. It does not take that much heel of the boat to make the boom appear to be drooping, so to me 10° rise makes sense. The extra rise also adds quite a bit to the sheeting clearance (Dmin), which is critical on many rigs.

    Cheers, Arne


    Last modified: 23 Jul 2016 09:53 | Anonymous member (Administrator)
  • 23 Jul 2016 07:35
    Reply # 4151806 on 4151341
    Erik and Evi Menzel Ivey wrote:

    Boom/batten angle - I think that with cambered sails, batten stagger is less controlled by the batten angle but rather by the various parallels, including Hong Kong if used. 10 deg. seems to be standard but I am considering 7.5 deg or less to avoid too much rise of the boom. 


    Not entirely true, Erik. I once made a series of calculations of how much the angle to the horizontal should be increased when cambered panels were used, but I can't find it now. I do remember that an increase in the order of two degrees was needed with a heavily cambered panel. That is, nearer to twelve degrees than ten.
  • 22 Jul 2016 23:00
    Reply # 4151351 on 4138614
    Deleted user

    I also "cheated" on Flutterby's sail area and am still sorting out some of it. My existing masts are tall light carbon fiber masts, so I was able to put a lot of sail area on. The good news for coastal and protected waters sailing is that she feels like she is sailing in 5 knots of wind and goes quite nicely in 8-10 knots.

    The bad news is sheetlet snagging, etc. I'm still sorting it out, and am concerned that it will be worse offshore when I try that

    I've already given up using the 8th panel of my mizzen and don't miss it at all. Going from a 5:1 sheet to a 3:1 sheet was a big improvement, and now that I'm figuring out how to balance Flutterby's sails I find myself sometimes reefing the mizzen even more for balance. 

    One other note: you can set the boom/batten angle for proper reefing stagger with full cut cambered sails, but it won't work with the PJR calculations. David Tyler posted something for calculating that once here somewhere. 

  • 22 Jul 2016 22:38
    Reply # 4151341 on 4138614

    Darren:  We own a Freedom 40 Cat Ketch and I have struggled with similar issues as you are regarding sail size, panel size, boom/batten lengths, and Dm.   I am generally following Arne's designs including equally sized panels and batten lengths.  I by far not an expert, but maybe some of this is helpful.  And hopefully the real experts can chime in, too.

    Lead - I have been able to sail our boat in various conditions and I think we have a litttle too much weather helm when both sails are full size.  The new sails will have a COE approximately 50cm further forward.  Not sure if that is a lot or little, but it is pretty easy to adjust helm balance on our ketch by trimming the two sails differently, and once you are reefing you get to pick which one to reef first, so to balancing the boat will be easier then, too. I've decided not to worry about it too much.

    Sail size - Going smaller makes everything else easier.  We have approximately 73 sqm split between two sails.  I'm thinking of going as large as 86 sqm, equally sized, 7 panels.  But they may end up a tad smaller to help with other constraints.

    Boom size - similar to yours, at about 4.6 meters

    Yard angle - 70 deg.  I like the look. others are possible, esp if the yard is made shorter.

    AR - approx. 2.6

    Boom/batten angle - I think that with cambered sails, batten stagger is less controlled by the batten angle but rather by the various parallels, including Hong Kong if used. 10 deg. seems to be standard but I am considering 7.5 deg or less to avoid too much rise of the boom.  I would like to be able to reach the clew when the sail is reefed. Also the large empty space between the boom and deck looks awkward to me.

    Sheets - I currently sail with a 3x1 on 6 m long wishbone booms.  Total sheet length is 30 meters.  It ends up being a lot int the cockpit.  I would really like to avoid longer sheets.  The 3x1 gets you to a 5 point attachment setup on the junk sails, thus the 7 panel sail.  If the twist can not be controlled adequately, I could see going to two sheets before a 5x1, but that means adjusting 4 sheets during maneuvers - maybe OK for ocean sailing, not so much in close quarters.  

    Dm.  This is a struggle, esp. with me trying to keep the booms low.  Shorter booms help, but either the sail area drops or the AR goes up when I try for more D.   Kurt Ulmer on this site suggested varying the panel height in order to reduce the Dmin.  My sheet arrangement has a Dmin of 1.75P.  I have drafted a sail plan for an average P of 1.44, but the lowest P is 1.2 m, and the next two are 1.6, then back to 1.2 and 1.6.  This gives a D min of 2.3 m  vs 2.52 m.  The varying P doesn't look too weird, either.

    Material.  I've looked the Weathermax80 and really like it compared to the other standard options.  


  • 22 Jul 2016 05:17
    Reply # 4149544 on 4138614

    Thanks for the info Graham, sheets wrapped around the wind vane are on the list of things I would like to avoid.  It looks like there might be just enough room to build an arch/bimini and sheet to the back of that.  This would protect both the wind vane and the helmsman.  That will have to be my next doodle.

    Good to know that such a high AR sail can work.  Given other constraints, I'm not sure how I can avoid them.

  • 21 Jul 2016 23:27
    Reply # 4149371 on 4138614

    My sheet has occasionally fouled the windvane, despite having more drift than yours.  It often happened when I was tacking in stronger winds and the sheet blew aft, rather than when gybing as expected.  I have significantly improved the problem by putting a restraining horse or deflector across the cockpit just above the sheet.  I used an alloy tube lashed across the pushpit.  This deflects the slack sheet as it comes across and inhibits its tendency to catch the windvane. 

    Gybing created other problems.  I rarely do an all-standing gybe except in the lightest airs, preferring to leave the sheet cleated, but haul the slack out of it, flaking it down on the cockpit bench then letting it run out through gloved hands as it goes over.  (Provided the sail is squared right off before executing the gybe, I find that this is easy and stress free, but then my sail is only 35 sq m!)  When gybing with a slack sheet (all-standing), there is a lot of slack there and if it can find anything to take a turn around the damned thing will, in my experience.  Putting a lot of thought into eliminating snags on deck is well-worth it.  I have almost succeeded by this time but it still hooks under one edge of my cockpit roof occasionally.  I am thinking of ways to resolve this.  If I am successful, then I should finally be able to tack and gybe (and reef) on the blackest night with impunity, which is the required standard for offshore voyaging. 

    Your new sail plan has a higher aspect ration than PJR recommends but if you have some camber in the panels that should not be a problem.  Actually, I have a friend with flat-cut sails with the same aspect ratio as yours.  His sails develop a lot of twist but still seem to have plenty of drive to windward.  He has a very heavy boat so high performance sails probably would not make much difference.  Good luck with your project!

  • 21 Jul 2016 22:23
    Reply # 4149310 on 4138614

    I've redrawn the sailplan for Leeway in a more restrained version.  To get there I set the panel height at 50" (1.27m) and then progressively shortened the battens until the sheeting looked significantly better.  The final version, with 184" (4.67m) battens, now has 1062 sqft (99 m2) sail area.  Not surprisingly, the sheeting angles are better, it is possible to sheet the mainsail to the pulpit, and the halyard drift is better, although still a little under what PJR recommends.  The aspect ratio of the mainsail is now slightly outside the recommendation from PJR.  

    The mainsail sheet comes very close to the wind vane when the windvane is set for running.  I wonder if the sheets are likely to catch on it in a gybe?  Maybe I should increase the height of the tower of the vane as shown on the drawing?

    The allowable sheeting quadrant for the foresail now comes within 14" (36 cm) of the forward edge of the main mast.  I wonder if it might be possible to build a trussed-collar for the mast and use that as the sheeting point for the foresail?  That certainly would provide lots of real estate for dinghy storage.

    As always, any thoughts are appreciated.

  • 19 Jul 2016 22:15
    Reply # 4143282 on 4138614

    Thanks David and Asmat,

    I suppose I knew I was being too greedy about sail area and I was just in need of an intervention to make that reality apparent.  We do have a brand new Beta-50 and 230 gallons (870 L) diesel capacity, so motoring through the calms is an option.

    I have another JRA member visiting tonight, but tomorrow I'll need to take some measurements to see if I could make the sheeting to the pulpit work.  The Dmin would be much shorter, but the sheeting angle better.  Hopefully, I can leave sufficient clearance for the windvane.  I now understand why David's windvane has the vane mounted remotely on the davits...

  • 19 Jul 2016 16:11
    Reply # 4139830 on 4138614

    Darren, like David, I regret my greed for sail area at the expense of efficiency. Too little distance between the leech of my mainsail and deck anchorage of the sheet makes for messy gybes, with the sheet caught and unable to render freely. A royal pain if I'm running along a narrow, twisting channel. In future, I'll pay close attention to the parameters set out in PJR, based on Hasler and McLeod's experience and sound, seamanlike  judgement.

  • 19 Jul 2016 09:24
    Reply # 4139387 on 4138614

    I have to agree with your line "I may have been a bit too greedy in trying to fit in 1200 sq ft (113 m2) sail area". Whenever I've "been a bit too greedy", I've ended up regretting it. Taking the displacement as 14 tons and aiming for SA/D = 18, a sail area of around 1100 sq ft seems to be more than enough to carry out your mission statement. Tystie has a great deal less, and yet was at no disadvantage during my four Pacific crossings, the first stage of your planned voyaging - I do feel that a small but reliable iron topsail is a lot more useful and versatile than that extra 100 sq ft. A small diesel will get you trickling along economically at 2 or 3 knots when it's not an option to sit and wait for a wind. When you get away from the BC Inside Passage waters, a wind-free zone in summer, I venture to suggest that you'll find 1100 sq ft enough. Personally, I'd be happy with 1000 sq ft.

    And, of course, scaling down the total area to 1100 sq ft, with a batten pitch of around 1280mm and a batten length of around 4860mm, eases all of your design problems. More halyard drift, or shorten the masts a bit (4in top diameter seems really quite small when you're up at that height in a bosun's chair), and more sheet drift.

    With eight sheeted points on the main, and seven on the foresail, I feel that upper and lower sheeting is not only desirable, but essential. You have room for three-point spans - just - so it would be possible to use five-part single sheets; but I fear that you wouldn't get good enough control over twist. Nevertheless, since the amount of rope and hardware is much about the same, it's not too costly an experiment to start with single sheeting. Don't be too worried about over-stressing the battens with unbalanced upper and lower sheeting, I never found this to be a problem.

    I think you can move the foresail sheet deck blocks back a bit. That, and a dinghy with a raked transom, should allow reasonable foresail sheeting. I tried port and starboard sheeting, but found it to be unnecessary on the foresail.

    Can you sheet  the mainsail a bit further back by putting the deck blocks right back on the rail? Looking at my photos of Leeway, I think you can.

    I think you should consider a lightweight extension to the yards, to make sure they stay aft of the lifts. Nothing too big, maybe 2in diameter  at the most.

    You'll be aware that hinged battens are out of the question with so much foresail balance area, but you might consider them on the main.

    Last modified: 19 Jul 2016 21:54 | Anonymous member
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