Beach Catamaran Performance History

Technical discussion of ARC products
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Bill Roberts
Expert
Posts: 515
Joined: November 17th, 2003, 9:13 pm
Location: Stuart, Florida

Beach Catamaran Performance History

Post by Bill Roberts »

The following is a paste by Bill Roberts from the catsailor forum dealing with "the carbon Tornado discussion and faster boats".
Hi Macca,
The proof of speed is in the demonstration. I don't see anything as fast as the Tornado in this latest crop of "new designs". Look at Portsmouth Numbers for an unbiased source of relative boat speeds. The point is that good engineering and good design do not get old. I have been a part of catamaran design and performance for about 25 years. Over that period the only boat that was ever issued a PN lower than the Tornado was the Supercat 20. There was a time when the standard SC20 was 62 and the SC20TR was 60 while the Tornado was 64. These are the only 20ft boats to ever be rated faster than the Tornado. Today there is the ARC22 which is the SC20TR with the hull stretched 2ft in the front end; same mast and rig and boards and rudders as the SC20TR. Today the 22 with spinnaker has a PN 2.7% lower than the Tornado with spinnaker. This PN diference also has within it the fact that the ARC22 is sailed by good/average sailors and the Tornado, best data, is sailed by Olympic caliber sailors. This effect itself has significantly reduced the PN difference between these two boats.
So Macca, there aren't many new design ideas out there waiting to be incorporated into a Tornado beater. I remember when the H18 first came out and it was touted to be a Tornado beater. What a puff of hot air that was. The M20 is 140 pounds lighter in weight than the Tornado with a more efficient sail plan and high aspect ratio boards and rudders and the best it can do is sail even with a well sailed Tornado. Isn't that 140 pound weight reduction of the M20 worth something??? What's going on here? What's wrong? I guess good boat design and good engineering just doesn't get old. Maybe it is something like a good piece of art work where form is function.
Bill
dave trey
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Posts: 10
Joined: April 1st, 2004, 3:04 pm
Location: MICHIGAN

Post by dave trey »

Hello Bill and others.

I've enjoyed my SC17 many long years and appreciate that shared lift thru low drag, hard chine hull shape and hi lift foils, has made this a boat to enjoy.

Recently, multi-classes adopted skiff derived asymmetrics, most as ill concieved "me too" add ons without an eye to design. Again, our design with "made ready" forward CLR , exploits the kite's virtues without the "fight" at the tiller.

Moving forward, materials and rig, with proven cost concious builds, may merit a second look. While it is proven lower weight and new design don't make a winner, one might ask what attributes the "modern sailor" would die for.

First, lighter hulls for off water handling. Gel form molds are dated. Epoxy coat "modern" fabrics afford twice the strength at half the weight. Our easily driven hulls, now easier to lug about, sail faster in light air.

Lighter, perhaps lower aspect Carbon glass spars, serve to lower the CE. Borrowing once again from skiff (and iceboat) thinkers, build the GRM (gust reponse mechanism) into the spar. Twist inducing flex top masts will always be faster when married to correctly matched mains, especially in heavy air. This extends wind range and crew weights, merits most appreciated by older, less inclined or light "would be" users. Handling improves, sheet loads reduce, the design does the work. We would have a different "way to sail" !

I mention all the above as a plea for the hundreds of cat sailors I've met. Singlehanded trends, what with crew decline, begs for new design. Many small waterlined ill designed boats have hit the market in answer to demand. Many could experience (re-experience) the virtues of efficient, faster, longer beach cats.

This all just might point to a good business model !!

Dave Trey SC17, Lindahl LDC "A" Cat, Stiletto 27, Tasar(skiff)
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