--- In harryproa@yahoogrou
wrote:
>
>
> I fully agree with your ideas on placing rig CoE
> forward to make sail balance better. The reports on
> lot of pressure on aft rudder have made me think of
> alternative rigs to easyrig. The crab claw and gibbons
> seem to work well in smaller proas being effective
> rigs and placing sails forward to bow, but scaling
> them up to harry or visionarry size seems quite
> problematic.
>
> All my sailing experience tells me that boat should be
> well balanced. Easyrig seems very easy to handle but
> the rig/rudders combination doesn't seem balanced to
> me. Reports on the heavy pressure on aft rudder
> indicate that this is the case. Having better balance
> should also help to improve performance by reducing
> the forces needed to counter the forces caused by
> unbalance between sails and foils. In greater speeds
> this could be quite a big factor.
If you regard the rear foil as the main leeway prevention, I do not
see how it thus becomes unbalanced. The load on a centre board is
large and if you lift it up , the boat becomes unbalanced. If you
have plenty of depth for the foil, then there is no problem. You may
have to adjust the position of the pivot to lighten the load, but
that does not mean the boat is unbalanced. If it was truly
unbalanced it would not be able to go upwind and downwind and sail
at windspeed. What we are asking for is that the boat can sail
without undrwater appendages. This is a big ask of any boat. .
If you wish to steer with a lighter rudder, you can fix the rear
one and play with the forward one. I was only thinking of a
situation where the boat could be sailed in skinny water using drive
from the forward sail to allow minimum foils in the water. In deeper
water, I have no problems with the system.
Robert
RObert
>
> What worries me regarding the crab claw and gibbons is
> lack of knowledge and experience on those. That is why
> I was so interested in your experiments. And handling
> of those rigs with crew of one or two persons may be
> too much.
>
> But I guess it takes considerable amount of testing
> and trial & error to get it right. I'm glad there are
> others gathering experience and information too.
>
> Arto
>
> --- tsstproa <bitme1234@.
>
> > Okay
> > ****
> >
> > To judge performance at that scale would be way over
> > my head at
> > such a small scale. I use models for simply testing
> > the effects of
> > balance from sail COE positioned in diferent
> > locations on different
> > hull type proa configurations. To which will give
> > best forward drive
> > with least amount of effort and best helm balance.
> >
> > Rig types for specific proa configurations.
> > I see in model test on harry type configuration
> > (Meaning low draft
> > hulls with weight to windward using deep boards)a
> > better more narrow
> > windward performance range from The easy rig
> > compared to the crab
> > claw rigged on the same harry type model. But I
> > think thats only due
> > to the easy rigs placement of the rigs COE being
> > back further and
> > relying on the single replaced longer rear board to
> > counter sail
> > force. Same harry type model with claw balances with
> > both boards
> > down or with just the rear down. Crab claw rig had
> > such netrual helm
> > I had to set steering boards to make proa go up wind
> > which it did
> > well but needing input to do it with both boards
> > down. Single board
> > down cause just enough weather helm to get model up
> > wind. But didnot
> > seem as efficient as easy rig or as well as
> > traditional hull proa
> > configuration with crab claw rig.
> >
> > Notice in this video with harry type hull
> > cinfiguration it is with
> > the old shorter boards. The 85 sq'' orange claw sail
> > balanced why
> > better than the the 50 ish sq'' sail on the easy
> > rig. with the easy
> > rig you can see the extra bit of weight about 1/4 oz
> > of sand on the
> > rear of lwh to keep model from round up and back
> > winding.
> >
> >
> http://youtube.
> >
> > So I guess the question would be how are you will to
> > gain your
> > performance.
> >
> > I personally think adapting modern technology to
> > mimic tradtional
> > methods in rigs felxablity. Is one way in advancing
> > proa technology.
> > look at clip below for an example.
> >
> > http://youtube.
> >
> > In the clip above: Thats a 45% larger sail area than
> > the old 50ish
> > sq'' easy rig sail on old shorter leeward hull with
> > the old short
> > baord sailing pretty balanced. Hope this gives you
> > some idea.
> >
> > Look in photo's under Square Harry. for lwh
> > comparison old vs new
> > and board comparison depth and size old vs new.
> >
> > Todd
> >
> > It wasn't the wording but how you presented and
> > edited that seemed
> > offensive!
> >
> > In harryproa@yahoogrou
> > <ahakkara@>
> > wrote:
> > >
> > > Todd,
> > >
> > > I did not mean to be rude or offensive. I am sorry
> > if
> > > you interpreted it that way. It is probably due to
> > me
> > > not being native English speaker.
> > >
> > > I understood everything you said in your mail
> > before
> > > this message. Reason I asked is that since the
> > > conditions may have varied more than was visible
> > in
> > > the videos I wanted to know if some rig performed
> > > considerably better than others speedwise or in
> > other
> > > way. I did notice that crab claw moved the model
> > very
> > > fast but was it because of change in condition or
> > > superior performance was the actual thing I wanted
> > to
> > > know.
> > >
> > > Also if crab claw would perform as well as Marchaj
> > and
> > > many after him indicate it would also solve many
> > other
> > > problems in proa. That is why I am very curious to
> > see
> > > and hear all test results.
> > >
> > > And again I am sorry if I insulted you in any way.
> > > That was never my intention.
> > >
> > > Arto
> > >
> > > --- tsstproa <bitme1234@> wrote:
> > >
> > > > If you cant see the difference then I doubt I
> > could
> > > > explain it in a
> > > > way you would under stand.
> > > >
> > > > my opening statment said in the thread in
> > regards to
> > > > sail/ sails.
> > > > Knowing that Doug said he thought his boards
> > needed
> > > > to be further
> > > > out towards bows for better control , for a less
> > > > heavely loaded
> > > > helm. I gave a possible solution instead of
> > rudder
> > > > design.
> > > >
> > > > But if you wanna come right out and call me a
> > tardo
> > > > or retard go
> > > > ahead. I just realized that some get there
> > groups by
> > > > email instead
> > > > of going to the web and picking out what they
> > want
> > > > to read. Sorry if
> > > > I have violated your email with my TaRdO SeNsE.
> > > >
> > > > Both Aframe and classic Crabclaw place Ceo of
> > sail
> > > > in a more foward
> > > > position off setting weight and drag to windward
> > > > with buoyancy shift
> > > > forand aft on a proa for best forward drive with
> > as
> > > > little under
> > > > water surfaces required for a specific under
> > water
> > > > hull shape to
> > > > achieve a balanced helm. Both rigs are flexiable
> > > > (meaning not afixed
> > > > to hull in anyone perminent location) allowing
> > for
> > > > each Type of
> > > > sails Ceo to be moved to a single location for
> > best
> > > > balance on all
> > > > point of sail.
> > > >
> > > > Todd
> > > >
> > > > --- In harryproa@yahoogrou
> > > > Hakkarainen <ahakkara@>
> > > > wrote:
> > > > >
> > > > > In the threat regarding rudder design we saw
> > some
> > > > > tests by Todd with different rig
> > configurations:
> > > > > *****
> > > > > Here are my two solution in getting sail area
> > to
> > > > the
> > > > > correct
> > > > > location for both tacks for both bows. One
> > evolved
> > > > > from the other.
> > > > > One balances traditional the other modern.
> > > > >
> > > > > http://www.youtube.
> > > > > http://www.youtube.
> > > > >
> > > >
> > >
> >
> http://www.youtube.
> > > > >
> > > > > Todd
> >
> === message truncated ===
>
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