Forgot password

Windvane selfsteering gear questions

  • 14 Aug 2011 16:08
    Quote
    Reply # 675982 on 675888
    Deleted user
    Paul Thompson wrote:
    Jeff McFadden wrote:Paul,
    I have nothing to contribute to this question but am immensely curious.
    Seablossom is, like La Chica, a double-ender, even shorter, and has a stern mounted rudder. She has Monitor wind vane brackets. Of course, I don't need a wind cane on my lake, but it is a very interesting thought to me nonetheless.

    Jeff,

    If you have the Monitor,

    Oh how I wish.  The Monitor was listed as an extra cost option in the original listing for the boat, but it was long gone before I bought her.  All I have is the Monitor brackets, installed on the boat.  Even they could easily prove useful.

      you will not regret putting it on. Even for lake sailing it is wonderful not to be tied to the helm all the time.

    I suspected as much.  It's a very big lake.  One could be tied to the tiller for a long time reaching the long way across it.

    I would not copy Easy Go's design for your boat. Full keel boats with rudders on the end of the keel such as your Seablossem and my La Chica tend to have heavy helms and the type of vane that Robert built for  Easy Go is unlikely to work well if at all for us.

    I rather suspected as much.  When Robert said he had a balanced rudder, a bell went off in my head and a voice said, "You don't!"

    Of cause, if you are able to build it for the same cost as Robert managed to do, there is nothing to stop you from trying. At worse you loose ten bucks and some time.
    A generous soul recently sent me an electronic copy of Belcher's book, so after I get her launched and sailable, I can look into a wind vane as an early improvement. 
    Last modified: 14 Aug 2011 16:09 | Deleted user
  • 14 Aug 2011 08:53
    Quote
    Reply # 675888 on 673673
    Anonymous member
    Jeff McFadden wrote:Paul,
    I have nothing to contribute to this question but am immensely curious.
    Seablossom is, like La Chica, a double-ender, even shorter, and has a stern mounted rudder. She has Monitor wind vane brackets. Of course, I don't need a wind cane on my lake, but it is a very interesting thought to me nonetheless.

    Jeff,

    If you have the Monitor, you will not regret putting it on. Even for lake sailing it is wonderful not to be tied to the helm all the time.

    I would not copy Easy Go's design for your boat. Full keel boats with rudders on the end of the keel such as your Seablossem and my La Chica tend to have heavy helms and the type of vane that Robert built for  Easy Go is unlikely to work well if at all for us.

    Of cause, if you are able to build it for the same cost as Robert managed to do, there is nothing to stop you from trying. At worse you loose ten bucks and some time.
  • 14 Aug 2011 08:45
    Quote
    Reply # 675887 on 673518
    Anonymous member
    David,

    Thanks for your detailed response, especially your comments about installation and the remark about raking  the gear forward so as to make sure that the pendulum tab is trailing. This agrees with my own exsperiance and observations with La Chica.

    When I installed the Monitor on La Chica, I installed it as recommended. Namely with 0 deg rake. The gear worked well for La Chica and I seldom have had to steer for more than an hour or so on each voyage. However I did notice that whenever I had both my diesel tanks full, the Monitor seemed to struggle to do its job. And now I understand why.

    On La Chica the diesel tanks are under the cockpit which is right as far aft as you can get it. After filling the tanks, she always trims down at the stern and of cause the pendulum would the rake forward.

    I will take care that the Cape Horn (it is the Joshua model) rakes the full 5 deg forward. Thanks for that tip.

    As to trimtab gears, I'm with Slieve on this one. The reason why most commercial gears are of the pendulum type is because being so powerful and with very good yaw damping, they can be guaranteed to steer just about anything. Trimtab gears on the other hand, need to be carefully intergrated into the existing structure of the boat and your rudder design needs to take the negative effects of the trimtab into account. There are a lot of Brent Swain designed boats around that steer beautifully with their trimtab gears.

    But point taken, I want to get La Chica into the water, so I'll put the Cape Horn gear on, seeing that all I have to do is weld the brackets on to the bumpkin and it will be set to go.
  • 14 Aug 2011 08:00
    Quote
    Reply # 675875 on 673518
    Anonymous member
    David, you've written a most interesting and useful set of comments on vane
    gears. Thanks.

    In his book 'Self Steering Under Sail' which can be downloaded free from the
    Windpilot web site, Peter Forthmann admits that the Windpilot Pacific has
    the shaft angled back 10°.

    A friend of mine set out from Ottawa some years back in a Bristol 41 with a
    Cape Horne gear installed by Yves himself. I met up with him in the south of
    Spain and he told me the gear hadn't steered for more than 20 miles on the
    Atlantic crossing, and he had used the autopilot instead. I went out for an
    hour with him but in only 4 kts of wind to see if I could make sense of it,
    and couldn't. The steering lines went from the gear segment through a fools
    purchase and then to the rudder quadrant, but the rest of the drive to the
    large steering wheel (flywheel) was still connected. The work required to
    steer the boat that way was ridiculous. When I disconnected the gear and
    controlled the wind vane by hand due to the lack of wind the pendulum just
    went wherever it wanted to regardless to the steering input, and we even
    tried it with the propeller stopped after driving up to hull speed. It just
    did not make sense, and at that time I thought it was just floating to the
    surface as the servo blade had about 130 cm in the water, which I thought
    was far too long. The wind wane was rather small.

    Now at last you may have the answer in that the gear may have become swept
    forward due to the loading of the stern. I didn't check that, but even so
    the pendulum blade was not prepared to swing in the direction it was
    pointed. The gear was eventually removed and sent back to Canada for an
    expensive refund, and the circumnavigation completed with and sometimes
    without the autopilot.

    David, you mentioned a dislike for trim tabs, and there I can't full agree
    with you, IF the system is designed correctly. The Boing 737 could be flown
    with all power controls and engines switched off by manual control of the
    trim tabs on all the flight control surfaces. It was very heavy, but a great
    back up system and all the pilots felt comfortable with it. On the other
    hand, as you say, adding a trim tab to an existing rudder decreases its
    effectiveness a lot and is unlikely to give a satisfactory result. The
    arrangement must be fully designed with the trim tab included, and there are
    not many amateurs who can do that. Bill Belcher's book does give some good
    pointers.

    The pendulum gear is just a trim tab gear, but with the trim tab arranged to
    turn it the 'right' direction working with and not against the rudder and
    coupled to the rudder with strings. Jan Alkema has designed a pendulum which
    fits directly onto an outboard rudder and is effectively a reverse direction
    trim tab. It has been reported in AYRS and on Cruisenews.net forum in some
    detail, and also in PBO I think. By all accounts it works very well and
    could be of interest to some JRA members with outboard rudders. It would not
    be expensive to make.

    Cheers, Slieve.
  • 13 Aug 2011 11:03
    Quote
    Reply # 675410 on 675145
    Deleted user
    Jeff McFadden wrote:
    Robert Groves wrote:I've posted a picture of the Wind Vane that we use on Easy Go in my members photos. It is light, easily adjusted and has no underwater parts. It has worked flawlessly and was made up of some scrap wood, a few bolts and some line to the tiller. Total cost for the original was about $10 CDN. With two crossings of the Atlantic is is certainly the most cost effective wind vane around.

    Robert,

    I looked carefully at your wind vane system, then went and read some manufacturers' literature, particularly Monitor.  They, and David, seem to agree that without a servo pendulum the wind vane itself won't have enough power to steer the boat, but yours obviously does.
    Easy Go is similar in size to Seablossom, and both have the canoe stern and transom mounted tiller, but of course Easy Go does not have the full length keel and probably responds more quickly and easily to the tiller.  Still, your system is quite interesting.
    I take it that the tan or brown disks are your adjustment point, and that you take the tension off the line fastened to the upper disk, adjust your vane to the proper orientation, and cleat off the line, correct?
    I am wondering, though, if your ability to balance Easy Go to sail almost without help by using her two sails is a factor which might restrict using your design from a junk sloop.  Any ideas?

    I used the design for this windvane from the book "Wind-Vane Self Steering"  by Bill Belcher. It is the Mark 2 design. The vertical vane works well on all points of sail with our two masts, relatively long keel and a balanced rudder. Don't know how it would perform on a long keel with keel mounted rudder and single mast but I'd be willing to give it a try. I was really surprised at how powerful the vane was and shortened the distance from the rudder's center point to the connection point for the control ropes to less than .5 meters and it still is more than powerful enough! Balancing the sails is only marginally helpful for this steering gear. It is extremely powerful. I had my doubts about this vane as well but with the cost of a commercial unit the experiment turned out to be very worthwhile.

    You are correct in the analysis of the adjustment point. The original design was to bring forward the lines to the hatch so that one didn't need to go on deck to do the adjustments. Need to try that sometime in the next level of refinement.

    With Belcher's designs one could make this vane into a servo pendulum or rudder mounted steering with the adaptations given in Belcher's book. He also has several other designs including servo pendulum. Well worth getting a copy.
    Last modified: 13 Aug 2011 11:09 | Deleted user
  • 13 Aug 2011 07:58
    Quote
    Reply # 675316 on 674974
    Anonymous member
    Barry & Meps / Stellrecht & Schulte wrote:
    David Tyler wrote: (in a couple of places; snip, snip)
    ......A word about installing any kind of pendulum vane gear: They work a little better if the aft end is tilted up very slightly, no more than 5 degrees.


    But the second point makes me think.  Scanmar instructs me to mount it so the paddle vertical.  I could try to angle up the aft end just a teeny bit (1~2 degrees), which would keep it angled that way even if she gets loaded down at the stern a bit.

    Does this sound like a good idea?

    Thanks,
    Barry
    Yes, Barry, a good idea. As I said, the Windpilot people have seen the benefit, and the angle on their pendulum is at least 5 degrees, by eye. If you went as far as that, you might get some comments from dockside loafers, but 2 degrees is certainly going to help. Consider as well the fact that the water is actually not flowing horizontally at the stern but is tending to rise into the stern wave (at speed, anyway), and I have to wonder why the vertical pendulum has been the norm for so long.
  • 13 Aug 2011 02:31
    Quote
    Reply # 675145 on 674651
    Deleted user
    Robert Groves wrote:I've posted a picture of the Wind Vane that we use on Easy Go in my members photos. It is light, easily adjusted and has no underwater parts. It has worked flawlessly and was made up of some scrap wood, a few bolts and some line to the tiller. Total cost for the original was about $10 CDN. With two crossings of the Atlantic is is certainly the most cost effective wind vane around.

    Robert,

    I looked carefully at your wind vane system, then went and read some manufacturers' literature, particularly Monitor.  They, and David, seem to agree that without a servo pendulum the wind vane itself won't have enough power to steer the boat, but yours obviously does.
    Easy Go is similar in size to Seablossom, and both have the canoe stern and transom mounted tiller, but of course Easy Go does not have the full length keel and probably responds more quickly and easily to the tiller.  Still, your system is quite interesting.
    I take it that the tan or brown disks are your adjustment point, and that you take the tension off the line fastened to the upper disk, adjust your vane to the proper orientation, and cleat off the line, correct?
    I am wondering, though, if your ability to balance Easy Go to sail almost without help by using her two sails is a factor which might restrict using your design from a junk sloop.  Any ideas?
  • 12 Aug 2011 20:58
    Quote
    Reply # 674974 on 674483
    Deleted user
    David Tyler wrote: (in a couple of places; snip, snip)
    .....Given that you have a [windvane] gear all ready to install .... I wouldn't be giving the matter any more thought than how to install it well....

    ......A word about installing any kind of pendulum vane gear: They work a little better if the aft end is tilted up very slightly, no more than 5 degrees.

    Wow!  Yes indeed, thanks for all this information, even if I will need to spend an hour scratching my head and sketching things to understand half of it!

    Meanwhile, I'm thinking about my situation, similar to the one above:  I've got a monitor just about ready to install when I return to Flutterby.  I plan to follow the first bit I'm quoting (adapted from Cape Horn to Monitor).

    But the second point makes me think.  Scanmar instructs me to mount it so the paddle vertical.  I could try to angle up the aft end just a teeny bit (1~2 degrees), which would keep it angled that way even if she gets loaded down at the stern a bit.

    Does this sound like a good idea?

    Thanks,
    Barry
  • 12 Aug 2011 12:11
    Quote
    Reply # 674651 on 673518
    Deleted user
    I've posted a picture of the Wind Vane that we use on Easy Go in my members photos. It is light, easily adjusted and has no underwater parts. It has worked flawlessly and was made up of some scrap wood, a few bolts and some line to the tiller. Total cost for the original was about $10 CDN. With two crossings of the Atlantic is is certainly the most cost effective wind vane around.
  • 12 Aug 2011 07:25
    Quote
    Reply # 674541 on 673518
    Anonymous member
    I'm glad someone drew out David's detailed knowledge about vane gear.

    I gained at least one 'Hmmm...' insight from his words about inclining the gear forward a bit. In our case, I installed our Cape Horn vertically with respect to proper trim, then loaded the boat for long distance. Down by the stern.

    That may explain why Yves (our Cape Horn) has wanted us to go somewhere else at times.

    (mehitabel's in much better fore-and-aft trim now, without a diesel motor and 1/4" plate fuel tanks.)

    Cheers,
    Kurt

       " ...there is nothing - absolutely nothing - half so much worth doing as simply messing about in junk-rigged boats" 
                                                               - the Chinese Water Rat

                                                              Site contents © the Junk Rig Association and/or individual authors

Powered by Wild Apricot Membership Software