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Sheet to tiller self steering, windvanes, and autopilots

  • 12 Feb 2014 23:56
    Quote
    Reply # 1496947 on 1493031
    Anonymous member
    I was lately inspired by necessity and also by David's various dxf files to rediscover my CAD skills. I installed libreCAD and gave myself the homework assignment of copying Belcher's OGT windvane diagram. My next assignment was going to be drawing up David's windvane design from the photos I took this fall, but it seems he's preempted that assignment with a drawing of his own that I can start with.

    I was partially interested in using a windvane project as an opportunity to explore using a lasercutter on plywood. It's probably not necessary, but with all the CNC plywood boat kits I'm surprised I haven't seen a set of parts for a DIY windvane, but maybe I haven't looked far enough.

    If anyone is interested in the Belcher windvane dxf I can email it to you or perhaps someone can put it up in the files area. 
    Last modified: 13 Feb 2014 02:39 | Anonymous member
  • 12 Feb 2014 23:12
    Quote
    Reply # 1496927 on 1496919
    Anonymous member
    Arne Kverneland wrote:

    My conclusion after reading the postings above, is that the Junkrig has now become so easy to handle that you are about to get bored ☺, so now you must find a way of keeping yourselves occupied underway. Personally, I would rather learn astro-navigation, Esperanto, or even knitting, than replacing a good selfsteering device with an awkward one.

     

    Arne

    I'm with you there, Arne. 
    I get out of harbour, rotate the vane to the right position, connect the servo lines to the tiller - job done, until the wind changes. No need to steer the course that a sheet to tiller arrangement would have me steer, because it can't manage the course that I want to steer. Once a good, able vane and servo system has been fitted, nothing else should be needed until the wind drops to zero and you set the iron topsail - then, I will  admit, an autopilot can steer better.
  • 12 Feb 2014 23:00
    Quote
    Reply # 1496919 on 1493031
    Anonymous member (Administrator)

    My conclusion after reading the postings above, is that the Junkrig has now become so easy to handle that you are about to get bored ☺, so now you must find a way of keeping yourselves occupied underway. Personally, I would rather learn astro-navigation, Esperanto, or even knitting, than replacing a good selfsteering device with an awkward one.

     

    Arne
  • 12 Feb 2014 22:25
    Quote
    Reply # 1496893 on 1496512
    Anonymous member
    Robert Leask wrote:For me sheet to tiller is one of the basics. Reliable self steering is a fundamental of offshore sailing and the more ways you have to do it, the better. 

    I have known a couple of sailors who used staysail sheet to tiller self steering on their gaff-rigged cutters for hundreds of thousands of miles.  They never sailed straight downwind, but chose to broadreach instead.  The staysail was sheeted in more tightly than the other sails and the sheet led to the windward side of the tiller, counterbalanced with shock cord.  It would be very interesting to experiment with this on a two-masted junk rig, though I cannot see how it would work with a single-masted junk.  I would not want to use the system Donald Ridler did on Erik the Red, as I think it is unwise to let the sheeted battens go beyond athwartships, and Donald suffered a lot of rig damage during his trip.  His were desperate measures for a desperate situation, sailing a bare-bones basic boat with no money for even a rudimentary windvane (he barely had enough food).  I have a lot of admiration for his pluck, determination and imagination.
  • 12 Feb 2014 18:48
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    Reply # 1496668 on 1493031
    Anonymous member
    Whew, now the scope of this topic has been widened, I can post this without getting my wrist slapped.

    I've made a folder "Vane Gears" in my Google Drive and into it, I've copied the drawing of the vane gear that Annie and I made for Fantail, and also a drawing that I started, incorporating the best features of the gears on Tystie and Fantail in a form that can be made by anyone who can cut and weld stainless steel, and turn some bearings out of plastic bar, without specialist tooling and jigging being needed. These are not complete plans for amateurs to use, as yet, but they can be used by engineers who are able to read dxf files, dimension the parts, and then go to the workshop bench to cut metal. If there's any interest, I might go back to the drawings and do a little more work on them.
  • 12 Feb 2014 17:58
    Quote
    Reply # 1496639 on 1493031
    Deleted user
    Amazing how easy it is to drift off topic... Now then, guys, Graham Cox will soon be in charge of moderating this forum, and he's just taken a day off his latest cruise to check up on you. He has asked me to add 'windvanes, and autopilots', to the title of this thread. So I have. Watch out, watch out, Graham's about...
  • 12 Feb 2014 14:31
    Quote
    Reply # 1496512 on 1493031
    Anonymous member
    For me sheet to tiller is one of the basics. Reliable self steering is a fundamental of offshore sailing and the more ways you have to do it, the better. It may not be possible on all boats and all rigs but if it is, then I think it's worth the effort to set it up, even if it's only as a last resort if all else fails. Because they all can fail. I've had autopilots give up (several) and servo rudders break off. I've never seen an autopilot that could cope with big breaking seas. My Aries was worth its weight in gold in heavy weather but not good in lighter winds because of my single masted rig which was not well balanced. When there was little or no wind, out came the tillerpilot. Most of the time in moderate conditions I used sheet to tiller and it would work for days on end with nothing to do but watch for signs of chafe and wear. My experience was that it also improved my speed. Using a headsail for steering kept the most effort in the main, and less downward pressure on the bow. I made my best daily mileages using good old sheet to tiller, I'm a big fan, and I wouldn't want to go offshore without it.
  • 11 Feb 2014 16:04
    Quote
    Reply # 1495752 on 1495595
    Anonymous member (Administrator)
    Gary King wrote:
    A DIY vane is a lot of work because every boat is different.


    Well, every boat is different, even  if you plan to install an off-the-shelf windvane. You then risk paying heaps of dollars (or whatever) for something that doesn't fit the boat. I'd rather invest a few days on making a windvane. If I can make something, then I can also repair it.

    Arne
  • 11 Feb 2014 12:03
    Quote
    Reply # 1495595 on 1493031
    Deleted user
    Hi Arne. I assume you mean me? (Gary and Ashiki)
    Our rudder is on the heavy side and reacts to waves easily. Not balanced enough at about 5% and close to Jay Benfords drawing, Belcher recommends ~18%. Can't do much about that now.
    Thus making the trim tab bigger, vane bigger and fixing the dud linkage (it was a turntable setup - not one of my best ideas)
    The vane was OGTII, about half the power of EasyGo's OGTI. I've enlarged it to be an OGTI.
    The Trimtab was 15% of rudder area when it should be 25% (now fixed).
    All I can think of is maybe EasyGo's rudder has a few % more balance than Ashiki's.

    A DIY vane is a lot of work because every boat is different.
    Last modified: 11 Feb 2014 12:55 | Deleted user
  • 11 Feb 2014 10:19
    Quote
    Reply # 1495571 on 1493031
    Anonymous member (Administrator)

    Stavanger, Tuesday

     

     

    David, the windvane on Ashika  looks to be big enough  -  I guess that big hole is covered with canvas when in use (..like the wings of the classic Dutch windmills…). Your rudder looks very similar to the one on Bob Groves’ Easy Go, and his “Reggy, the Regulator” actually worked well, directly on the tiller (just as my “Otto” worked on my Malena’s tiller). I therefore guess that the trimtab is the problem.

     

     

    Questions:

    1.       How are the tiller forces when hand-steering your boat today? If there is still some forces needed, then it could be an idea to shave a bit off the rudder’s trailing edge, in small steps, until the forces gets light (but not over-balanced)

    2.       Is the boat itself directionally stable? If not, you either should add a skeg to correct that, or you may need a more powerful selfsteering, a servo pendulum or something.

     

     

    As for sheet to tiller self steering; I cannot understand why anyone will bother. It only takes a couple of days to make a proper windvane from wood and plywood, and they work at all points of sailing.

     

     

    Cheers, Arne
       " ...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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