SibLim update

  • 29 Jun 2020 08:13
    Reply # 9066863 on 9065481
    Anonymous wrote:

    By the way, can anyone remember the derivation of the name "Brownstick"? I seem to remember that it was invented by someone called Brown, but can't find any written sources to verify that. Might it be second cousin to the RAF's "joystick"?

    I tend to remember that the name and article were given to the cocoction made to stear Jim's Brown playwood made trimarans from the USA back in the 60s.
  • 28 Jun 2020 14:25
    Reply # 9065481 on 4315719

    By the way, can anyone remember the derivation of the name "Brownstick"? I seem to remember that it was invented by someone called Brown, but can't find any written sources to verify that. Might it be second cousin to the RAF's "joystick"?

  • 28 Jun 2020 09:58
    Reply # 9065280 on 4315719

    Uffa Fox: "Simplify and add lightness".

    Having a couple of days in hand before collection by the courier, I've actioned the second part of that dictum, and added a little more elegance as well. Mass balance and low rotary moment of inertia are important parts of a good vane gear design.

    [The sharp-eyed observer would have noticed that the top of the latch plate was scratched - most of the materials used were upcycled/repurposed/rescued from my dusty boxes of scrap. Cutting away the sides to a concave shape got rid of one of these scratches, adding even more elegance]

    Last modified: 28 Jun 2020 10:05 | Anonymous member
  • 27 Jun 2020 23:43
    Reply # 9064751 on 4315719

    PS. Have you ever seen anything that combines simplicity with elegance so wonderfully well?  A miilion thanks to The Great One.

  • 27 Jun 2020 23:37
    Reply # 9064733 on 4315719

    1.  If it's obsolete it works

    2.  Sailing boats aren't motor cars.  They ate much more dynamic and in a much more dynamic environment.  Apparently adjusting course 3.5° or even 7° doesn't necessarily mean that this is how far the boat will change its heading.

    3. The Brownstick also enables you to alter course temporarily, eg to avoid an obstruction or a ship, without resetting the vane gear.


  • 27 Jun 2020 18:28
    Reply # 9064245 on 9064113
    Mark wrote:

    KISS !

    If you had a second alternative hole for the peg, half a notch out, you could adjust course by 3.5deg?

    Only if the peg is inserted manually, and the latch plate doesn't rise. Not with remote course setting, using a line to lift the whole latch and a Brownstick to nudge the latch one way or the other.

    The Aries has a similar step between its ratchet teeth.

  • 27 Jun 2020 17:05
    Reply # 9064113 on 4315719

    KISS !

    If you had a second alternative hole for the peg, half a notch out, you could adjust course by 3.5deg?

  • 26 Jun 2020 16:07
    Reply # 9062241 on 4315719

    Annie has entrusted me with making the latch mechanism of the vane gear. Being an old-fashioned girl, she wants a simple, easily understood, disc-and-peg kind of mechanism, as in Bill Belcher's fig 46 (a), and the client is always right, so who am I to argue? ;-)

    I've based it on a 52 tooth aluminium chainring. This gives 7˚ of course alteration per tooth:

    The latch is made from a 60mm diameter nylon bar screwed to a 8mm PVC sheet and sliding on a 3/4" diameter stainless steel tube vaneshaft. There are two holes athwart the vaneshaft for cords that will lead forward to the Brownstick (for those unfamiliar with this kind of antediluvian vane gear, it helps if the latch can be nudged one way or the other to put on a bit of weather helm before dropping the peg into engagement, so the Brownstick, a short piece of wood, is attached to those cords so that one or the other can be pulled a little):

    There is a brass bearing in the bottom end of the vaneshaft which will rest on and pass through a piece of 10mm HDPE sheet mounted on the inside face of the lute (the upper end of the vaneshaft passes through another piece of 10mm HDPE sheet screwed to the top of the lute):

    A brass peg is tapered so as to engage easily with the chainring. A M8 bolt will engage with the crosslink attached to the tab tillers:

    PS This is going right back to the Hasler trim tab gear, circa 1960.


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    Last modified: 28 Jun 2020 08:06 | Anonymous member
  • 23 Jun 2020 23:33
    Reply # 9055767 on 4315719

    I quickly created a test blog, using (seemingly) the same custom theme you're using on your blog but even though I have lightbox enabled in settings (it is by default) it still doesn't work - clicking the image just makes the browser navigate to a new "page" showing the image. Which means I can't reproduce the issue. Will try to find some time to play around with this further.

  • 23 Jun 2020 22:36
    Reply # 9055656 on 9055533
    Annie wrote:

    My blog gets posted to me and it read perfectly on both my phone and my tablet, but looks a little different from what I actually posted, which is usually the case.  I suspect that I inadvertently "optimised" it for hand held devices.  At the bottom of the screen were several icons - a phone, laptpp, desktop pc, etc.  I hate pictogram - what's wrong with words? - and didn't bother to work out what they are for.  I'll check next time I post.

    Aha, you're onto something. It displays correctly and in mobile-friendly format on my iPhone, and on my iPad in portrait mode, but not on my iPad in landscape mode or desktop.
    Last modified: 23 Jun 2020 22:48 | Anonymous member
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