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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> >
>