Todd,
<<Well with all that kite experience you of all people should
now where I'm coming from but apparently not. Buggies roll on
bearings Kite surfing you push through water big difference In power
needed and control well maybe not control but definitely power
required on average.>>
You're right about buggies needing more control. The consequences
of a gust in a buggy, over hard sand, traveling on bearings, are
definitely more pronounced than a gust when in the water on a
kiteboard.
In fact, I developed my kite control abilities to the point where,
back in 1998 in Hull Massachusetts, I was able to ghost past the U.
S. national champion, Jeff Howard, in two knots of wind, while
balanced on two wheels, while he was struggling to keep his kite in
the air with all three wheels on the ground.
I'm sure Jeff could have slaughtered me in a high wind, but low
wind is where the real skill and finesse lie. So I'm certainly
familiar with the process.
What I don't get is how this compares to the cambered
square/dynarig. I don't see the separate power and control lines,
nor how to adjust the trailing edge so that the wing tends itself in
a high wind.
I may need to be shown with the actual experience you talk about
elsewhere, how the sail can go to neutral in a blow and stay that
way as the wind changes speed and direction. Full-size would be
great, but a model might help illustrate.
Btw, your discussion of control does hint at an interesting
difference in our thinking: since my focus is on how to maximize
low-wind performance, without high-wind performance requiring
constant attention, I likely value different rig capabilities than
you do.
I'm not likely to beat Jeff Howard in a stiff breeze on a buggy,
and I'm not likely to want to push a proa past fifteen knots most
days (though I'd like to hit twenty at least once). I just want to
be king of the zephyr, without having to worry about things when the
wind really picks up and I'm alone in the middle of nowhere.
- Mike
tsstproa wrote:
Well with all that kite experience you of all people should now where I'm coming from but apparently not. Buggies roll on bearings Kite surfing you push through water big difference In power needed and control well maybe not control but definitely power required on average.
Maybe you need a better kite or better tuned. I can tune my surfkite leave and go pee just by adding a few short pieces of bungee. Whats that have to do with a fixed wing? I can stand with a 16meter in 30mph winds and not get yanked around by changing AOA of kite.
Scaled effect will be alot slower than the model . I can shunt model with out popping the windward hull. But I'm just tring to see how fast I can get going in the opposite direction most of the time. Not so much on how to do a controlled shunt thats not a challenge for me. Plus I'm filming at the same time and the video perspective is not so great so your really not seeing the true performance and possibilities.
Square hulls heeled you would lose the benefit of performance from such hull forms sailing flat both hulls just skimming the water is the performance.
Your issues are appreciated and things to consider sure but not impossible to weed out with the right technology, lay out in design and with a newly learned sailing skill apart from traditional thought.
Todd
--- In harryproa@yahoogroups.com.au, Mike Crawford <mcrawf@...> wrote:
>
>
> I's possible that I'm missing something.
>
> Could you show me how to stall a square/elliptical rig, and leave it
> stalled for a few minutes, even if the wind direction changes or the
> boat drifts? That would do a lot to help me see the safety of the rig,
> and should be easily demonstrated on a model if it's possible.
>
> I've flow four-line kites since the 1990's, so I'm familiar with how
> they power and depower. My favorite thing is to use the kites on a flat
> beach during low tide, flying along on a three-wheeled kite buggy.
> Great fun. That said, I've never been able to just leave my kite alone
> while I get up to pee.
>
> There's also the worry of the momentary shock loading of the system
> during a shunt as the wing turns from one side to another. Your
> "Planning Proa squared" appears to demonstrate this issue, with the
> windward hull popping off the water momentarily during many of the
> shunts. Get hit with a gust at the same time, and the boat is gone.
>
> Which is not to say it's a bad rig. Your tests have clearly shown how
> fast it can be. I just personally have an issue putting this on a boat
> with a stove, fuel, water, head, and passengers.
>
> ---
>
> This is actually one big reason that I'm planning on a proa in the
> first place.
>
> If I dump my current catamaran in water less than 30' deep, it will
> likely cost me between two and six thousand dollars to replace the
> equipment that could get damaged. I love having a boat with an SA/D
> over 50, but it does worry me when pushing the boat. That kind of cost
> figure for a capsize tends to lead to white knuckles when flying a
> hull. Especially if I'm at an angle where dumping the sheets will
> actually increase the heeling moment, leading to a knockdown or pitchpole.
>
> So it's my dream to get a boat of similar speed, but with greater
> righting moment and longer waterline, and a more powerful rig that I can
> always just depower by letting go. Up to this point, you wouldn't think
> that fast and safe could go together with the same boat. But a WTW
> proa, or catprao, can be an impressive design.
>
> - Mike