Hi Fedor
Rob previously replied to a couple of my postings were I asked the same
question. My issue was the central (fore/aft) pivot points that were
slightly offset to port/starboard. I could see the setup inducing a lot
of torque. Rob's solution seemed to be to cant the blade
fore/aft which I now see would be easy to achieve with his design.
I would call it raking to me canting is a port/starboard slewing as in a
canting keel. It would be possible to both rake and cant at the same
time, but weather both would be necessary is another question. There
would plenty of scope with his design for tweaking
Rob Rassy
-- In harryproa@yahoogroups.com.au, "fvonballuseck" wrote:
>
> thanks got it! Question how does the rudder balance work - by canting
fore/aft?
> Fedor
>
> --- In harryproa@yahoogroups.com.au, "fvonballuseck" wrote:
> >
> > Did you find the presentation?
> > I went but could not locate it - any advice?
> > thanks Fedor
> >
> >
> > --- In harryproa@yahoogroups.com.au, "rob_rassy" wrote:
> > >
> > > Thanks for pointing that out Luc, I had missed that in the Pecha
Kucha
> > > presentation. I had assumed there would be a track from the 15M
schooner
> > > drawings. but this is a really nice simple solution. It pivots,
> > > turns lifts all with two component parts (excluding the
rudder
> > > blade pivot pin)
> > > I imagine there would be a cross hull tube for it to mount in, so
I
> > > wouldn't call it a hole as it would add strength to the hull and
not
> > > detract from it
> > >
> > > Rob Rassy
> > >
> > > --- In harryproa@yahoogroups.com.au, "LucD" wrote:
> > > >
> > > > In the recent Pecha Kucha presentation Rob shows a rudder design
I was
> > > not familiar with. I guess it is the one I could not decipher from
the
> > > drawings of the schooner vis on the hp web site. Of course
compromises
> > > are made (like there is a hole in the hull, symmetric foil, ...)
but it
> > > looks again so elegantly simple as I can already guess how the
potential
> > > disadvantages of some features are covered for by other parts. The
whole
> > > presentation to me is an illustration of the title that Rob
merits: Zen
> > > guru in the art of sailboat design. Maybe to bring out this image
to
> > > those not in awe by the drawings at first glance, Rob should shave
his
> > > head ;-) Marvelous.
> > > > Luc
> > > >
> > > > --- In harryproa@yahoogroups.com.au, "rob_rassy" wrote:
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > I agree Rob's original design is probably the best solution.
After
> > > all he did go out and do the actual testing and didn't lose sight
of his
> > > goal of lightweight and simple. They are proven to work and
achieve all
> > > the desired features (lift able, kick up, reversible, serviceable)
with
> > > a minimum of fuss
> > > > >
> > > > > My only concern with the original design is the lower pivot
mount,
> > > which I feel is to, low and will become a hand break when the boat
is
> > > pushed. I have considered other ways of mounting them higher but
the
> > > problem is the same as the beam mounts they get heavier the
further they
> > > are from the water
> > > > >
> > > > > My most recent thoughts are trim tabs on (close to) both ends
of the
> > > lee hull bottom to counter the asymmetric thrust /drag forces of
the
> > > Harry (weight to windward) design. They would be semicircular
> > > self-retractable (spring loaded), and set in slot at a fixed angle
or
> > > could be in a drum for extra adjustment and complication.
> > > > >
> > > > > If the rounding up forces were removed or reduced the beam
mounted
> > > rudders would come into calculation for me. At the moment I feel
the
> > > beams mounts are not wide enough apart to perform this job with
out
> > > being to large.
> > > > >
> > > > > I am open to being convinced otherwise though
> > > > >
> > > > > Rob Rassy
> > > > >
> > > > >
> > > > > --- In harryproa@yahoogroups.com.au, "von Balluseck, Fedor"
wrote:
> > > > > >
> > > > > >
> > > > > > Nice discussions!
> > > > > > Think the drum 'outside' is going to be in size comparable
to the
> > > first generation of rob's rudders - if not bigger - like on
Visionary.
> > > > > > Keep in mind those rudders are fairly big - and to get the
balance
> > > right the rudders have to be either angled or the moved
about15-20% back
> > > (longitudinal? ) So the drum is big - not sure but would guess
> > > 60-100cm's on Visionary.
> > > > > > Maybe you can reduce the size of the rudders if you go for
> > > additional leeway protection measures - but that stirs up the
> > > 'additional boards question.
> > > > > > Browse back in the posts - there was a long discussion on
multiple
> > > boards or a lee-board that could pivot. Rick W makes a point that
> > > against intuition and leeboard on the WW side of the lee hull
would be
> > > most efficient.
> > > > > > I believe Arttu's Ono visionary has added 2 boards to the
original
> > > 2 rudders - and he has shared some comments on how this is working
(but
> > > no protection against grounding)
> > > > > >
> > > > > >
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