-If the boat was only going one way at a time, why would you need lift
in both directions?
I still prefer the style of flipping the tiler over as you shunt as it
means you don't have either a tiller or a foil facing into the slop
Robert
-- In harryproa@yahoogrou
>
>
> You might have a good point there.
>
> On a boat that small, you could just flip one rudder up and one down
> each time you shunt, and with Harriette, it almost would be a wrist
> flip. Then you wouldn't have to worry about lifting anything, rotating
> the foils, or sliding a single foil forwards and aft.
>
> On the larger boat that would be a bit of a pain because you'd
have to
> move back and forth across the deck to reach each rudder. But on
> Harriette, if the tillers are long enough, you could probably
accomplish
> the maneuver without getting up.
>
> Then you'd get the added benefit of having just a single foil in the
> water (provided it's situated properly for steering and leeway
> prevention). With each rudder being a single foil used only in one
> direction, you might be able to use asymmetric foils for lift.
>
> - Mike
> / /
>
> Jim Baltaxe wrote:
> >
> > Hi All
> >
> > On a Harriette they would probably work a treat. You wouldn't be able
> > to have the front one down, though that probably wouldn't be much
of a
> > problem on such a small boat anyway.
> >
> > Enjoy
> > Jim Baltaxe
> > They said, get a life. I looked on TradeMe but I couldn't find one.
> >
> >
> >
> >
------------
> > From: harryproa@yahoogrou
> > [mailto:harryproa@yahoogrou
> > Sent: Thursday, 26 June 2008 10:56 p.m.
> > To: harryproa@yahoogrou
> > Subject: [harryproa] Re: rudder musing
> >
> >
> > We actually have this same rudder setup on our 27' Stiletto
> > catamaran, which weighs roughly 1300 pounds, and I believe the
> > company also used it on their 2400-pound 30' model.
> >
> > On the plus side, the system does work. It takes a bit more
> > than a flick of the wrist, but it's easy to raise or lower each
> > rudder with a single up/down arm motion. They also do kick up
> > automatically. We've watched that happen when hitting mud while
> > sailing where we shouldn't have been sailing, and also when
> > getting caught on lobster pot warps, which sometimes are
> > impossible to avoid with a wide-beamed boat.
> >
> > It's also great to be able to get rid of seaweed in a few
> > seconds without stopping the boat. We have not noticed any
> > significant wear, and since our boat was made in the early 1980's,
> > that's probably a good sign that the basic system is sound.
> >
> > I'm sure the system could be up-sized for the proas. However,
> > there would be a few problems and challenges in doing so:
> >
> > - The bearing surfaces would have to be quite strong and
> > low-friction. Kicking up a rudder on a 27' catamaran, where
> > leeway prevention is handled by a daggerboard, is quite different
> > from doing the same thing on a 40' to 50' proa where the same foil
> > handles steering and leeway prevention. The extra stress on the
> > foil would either require a special set of bearing surfaces, a lot
> > more force required for kick-up, or both.
> >
> > - The rudders only kick up in one direction. Assuming you
> > always have the rudders flipped to go "forward", this may not be a
> > showstopper.
> >
> > - The system does not offer variable draft. The rudders are
> > either out of the water, all the way down, or just barely in the
> > water (extending almost straight back). When they are just barely
> > in the water, the boat has a very serious weather helm, and that's
> > on a 27' catamaran with a daggerboard. The weather helm on a
> > larger proa would be incredible while sailing. It would probably
> > work pretty well while motoring, though.
> >
> > - The rudders will need some room. When they are up or
> > partially-down, they stick out of their brackets by their full
> > length. That means they wouldn't work if mounted on the hull, and
> > if mounted on the beam, they would need at least 4' or more
> > clearance on both sides -- the depth of the foil in the water plus
> > the distance from the water to the bracket which holds it.
> >
> >
> > I love the system on our current boat, but on a proa I'd
> > probably go with a version of one of Rob's beam-mounted schemes.
> >
> > - Mike
> >
> >
> > Arto Hakkarainen wrote:
> >
> >> If I looked correctly they only talked about boats up to 21' long
> >> and their rudders. Harryproa rudders are quite big and loaded
> >> compared to such small boat rudders. So it looked fine but will
> >> it scale to big enough size?
> >>
> >>
> >>
> >> Arto
> >>
> >> --- On Wed, 6/25/08, tsstproa <bitme1234@.
> >>
> >> From: tsstproa <bitme1234@.
> >> Subject: [harryproa] Re: rudder musing
> >> To: harryproa@yahoogrou
> >> Date: Wednesday, June 25, 2008, 10:06 PM
> >>
> >> I have seen those A couple of years back. Advertised in the
> >> back of
> >> Sail magazine. Not sure on how they actually work (the
> >> specifics)
> >> but seem like they could be adapted well to a proa with beam
> >> hung
> >> rudders.
> >>
> >> I was looking a the r/c retracts for airplanes to find out
> >> what type
> >> of mechanical advantage they use to raise gear with very
little
> >> movement from lever to move boards up /down 90 degrees.
> >>
> >> I have two types of micro retracts. They each use different
> >> mechanical advantages to achieve the same results.
> >>
> >> Studying these two types of mechanical advantages I'm certain
> >> I can
> >> come up with somthing for the 24'full size craft
> >>
> >> Both mechanical advantages are very simple.
> >>
> >> Have a look in square harry files section of diagram drawn.
> >>
> >> Todd
> >>
> >>
> >> --- In harryproa@yahoogrou ps.com.au
> >> <mailto:harryproa%
> >> <joooody2@ .>
> >> wrote:
> >> >
> >> > Hello All,
> >> >
> >> > I thought I would de-lurk for a moment to mention some
> >> rudders I
> >> found on the web some
> >> > time ago. I have no personal experience of them whatsoever
> >> (and
> >> no connection with the
> >> > company) but I thought at the time that they could be
good for
> >> proa use. I particularly like
> >> > the kick up function and the fact that raising / lowering
> >> can be
> >> achieved from the end of the
> >> > tiller without fiddling with uphauls etc.
> >> >
> >> > http://www.dotan. com/video/ <http://www.dotan.
> >> >
> >> > Chris
> >> >
> >>
> >>
> >
>
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