S2 6.7 Junk Rig Conversion

  • 16 Jul 2021 16:09
    Reply # 10756077 on 10755158
    Annie wrote:

    My trim tab plus vertical vane, on FanShi, is brilliant.  And not expensive or requiring any welding skills.  Can you do.something similar?

    Annie,

    A trim tab and some sort of vane seems like the right answer.

    The problem I see, when I imagine building this, is the kick-up rudder.

    If I have a trim tab attached to the rudder in the water and the top of the trim tab stock attached up above the pivot where the rudder kicks up then something is going to bend or brake if the rudder swings up.

    Is there a simple solution to this that I don't see?

    I should learn to draw :)


    1 file
    Last modified: 16 Jul 2021 16:10 | Anonymous member
  • 16 Jul 2021 15:58
    Reply # 10756062 on 10753964
    Arne:

    Scott,

    Test 1
    you could for instance drive your boat for motor in a straight line. Then you put the engine in free and leave the tiller. If the boat starts swinging into a steeper and steeper turn, to this or that side, then it is unstable.

    Test 2 (..if the boat went straight in test 1):
    Motor into a medium steep turn, set the engine in free and let the tiller go. If the boat straightens out the course, then it is definitely course stable.

    The quicker the boat straightens up, the better is the course stability.

    Arne

    I went out to my boat right around sunset yesterday. There was almost no wind and Lake Macatawa was very calm. I think there was just one power boat that briefly threw a wake across the water.

    Test 1: The boat goes straight after I put the engine in neutral and let go of the tiller.

    Test 2: The boat never straightens up. The tiller stays more or less where it was when I let it go, until the boat has turned around and slowed down. After slowing down, the tiller moves and puts the boat into a steeper and steeper turn.

    So ... it is stable until something pushes the rudder over, I guess.

  • 16 Jul 2021 15:21
    Reply # 10755983 on 10755274
    Zane wrote:

    A man with good taste (he sails a Contessa 26) made his own version of the trimtab SS and proceeded to do an Atlantic circle.  Details per the video

    https://youtu.be/Wcd9Y5AS6qE

    Zane,

    I had not seen this one before. Thank you for sharing it. In my opinion the price he is asking for plans and videos is very reasonable so I purchased a digital copy.

    The only big issue I see with me building this design is that there is some welding required. It appears to be one very simple weld, but I do not personally have any of the equipment or skills.

    Last modified: 16 Jul 2021 15:23 | Anonymous member
  • 16 Jul 2021 09:24
    Reply # 10755274 on 6872873

    A man with good taste (he sails a Contessa 26) made his own version of the trimtab SS and proceeded to do an Atlantic circle.  Details per the video

    https://youtu.be/Wcd9Y5AS6qE

  • 16 Jul 2021 07:17
    Reply # 10755158 on 6872873

    My trim tab plus vertical vane, on FanShi, is brilliant.  And not expensive or requiring any welding skills.  Can you do.something similar?

  • 15 Jul 2021 19:50
    Reply # 10753964 on 6872873
    Anonymous member (Administrator)

    Scott,

    Test 1
    you could for instance drive your boat for motor in a straight line. Then you put the engine in free and leave the tiller. If the boat starts swinging into a steeper and steeper turn, to this or that side, then it is unstable.

    Test 2 (..if the boat went straight in test 1):
    Motor into a medium steep turn, set the engine in free and let the tiller go. If the boat straightens out the course, then it is definitely course stable.

    The quicker the boat straightens up, the better is the course stability.

    Arne

  • 15 Jul 2021 18:36
    Reply # 10753839 on 10750959
    Arne wrote:

    Scott, there is also the OGT MkI model. It is a little bigger than Mk II, and Belcher reckoned it is twice as strong as the Mk II.

    It is not easy to sit on one's armchair and say "this will work" or "this will not work", in particular with windvanes. 

    It depends on the tiller forces on your boat. My 1.4ton Malena had an unbalanced rudder so tiller forces were noticeable.  If your tiller forces are high, then I would suggest the MkI vane directly on the tiller.

    In case the boat is directionally unstable, I suggest you fit a rudder-like thing on the transom and lock it in mid-position. That will act as a skeg, and can also work as a spare rudder if needed. You may well make this before you build a wind-vane.

    Arne



    Arne,

    I am not sure how to say if my boat is directionally stable or directionally unstable. Can you suggest some experiments to help me determine the directional stability?

    I do like the idea of having a spare rudder. I expect my boat would spin in circles pivoting on the keel if somehow the rudder became separated from the hull.

  • 14 Jul 2021 16:42
    Reply # 10750959 on 6872873
    Anonymous member (Administrator)

    Scott, there is also the OGT MkI model. It is a little bigger than Mk II, and Belcher reckoned it is twice as strong as the Mk II.

    It is not easy to sit on one's armchair and say "this will work" or "this will not work", in particular with windvanes. 

    It depends on the tiller forces on your boat. My 1.4ton Malena had an unbalanced rudder so tiller forces were noticeable.  If your tiller forces are high, then I would suggest the MkI vane directly on the tiller.

    In case the boat is directionally unstable, I suggest you fit a rudder-like thing on the transom and lock it in mid-position. That will act as a skeg, and can also work as a spare rudder if needed. You may well make this before you build a wind-vane.

    Arne



    Last modified: 14 Jul 2021 16:44 | Anonymous member (Administrator)
  • 14 Jul 2021 16:07
    Reply # 10750857 on 10749193
    David wrote:

    [...]

    If you are interested in a wind vane self steering just a simple horizontal axis vane direct to the tiller would probably work for a boat the size of your. In his book 'Wind-Vane Self Steering' Bill Belcher presents plans for a simple horizontal axis wind vane built fairly easily from plywood. If you are interested in building one of these I have the book and am happy to scan the plans and building instructions and email them through to you. It does require quite a large vane to generate enough power, but these simple vanes have been used successfully on many small yachts.

    David,

    Thank you for sharing the drawings. After studying them for a bit I remembered that Arne had built a wind vane, named Otto, mostly following the OGT MKII plans.

    Between the photos in Arne's write up and the drawings you provided I think I might be able to build a vane like this. I may not be terribly good at it, but I am comfortable working with plywood and epoxy. I may even be able to build this for less than the cost of a Simrad TP10.

    Near the end of his Otto summary, Arne wrote, "I would not suggest the same setup on a boat which is directionally unstable (or only just stable)."

    My boat (mostly) balances well on the wind, but on a run there is significant weather helm since the sail is almost entirely on one side on the boat. On flat water and consistent wind speed I can (mostly) correct for this by having the tiller off to one side.

    When I was out in some waves, and running down wind, the 'feel' on the tiller was changing constantly. As each wave passed under me the tiller would need more and more input to steer the boat until the wave was mostly passed at which point the tiller again became effortless to move.

    So ... is my boat directionally stable enough to hold a course using the OGT MKII attached directly to the rudder?

    Last modified: 14 Jul 2021 16:23 | Anonymous member
  • 13 Jul 2021 20:31
    Reply # 10749193 on 10749060
    Scott wrote:

    Thank you for the response. An electronic tiller pilot is tempting. They are, compared to most boat electronics, fairly inexpensive and appear to be easy to install.

    I have never used one in person but, from watching videos online, they seem to make a terrible noise. For motoring this would probably be OK since my engine is already so loud. For sailing I really want an almost silent boat so I can just listen to the water on the hull. 

    I would really like to have a hydrovane but they sell for significantly more than what I paid for my boat. I am pretty sure I will attempt to build some sort of vane gear. If I am ultimately unsuccessful then an electronic tiller pilot is plan 'B'.

    I am going through this exercise at present with my little catamaran. An electronic tiller pilot is quick and easy, and not hugely expensive. They just need sufficient battery power to keep them running for any length of time, and work best where tiller loads are light. I have used them and never found them to be noisy. For my previous yacht I bought a new Simrad tiller pilot and it was mostly hard to hear it operating. It was not silent, but then it did not make any kind of unacceptable operating sounds.

    If you are interested in a wind vane self steering just a simple horizontal axis vane direct to the tiller would probably work for a boat the size of your. In his book 'Wind-Vane Self Steering' Bill Belcher presents plans for a simple horizontal axis wind vane built fairly easily from plywood. If you are interested in building one of these I have the book and am happy to scan the plans and building instructions and email them through to you. It does require quite a large vane to generate enough power, but these simple vanes have been used successfully on many small yachts.

       " ...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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