Bolger and America's Cup

[Mark Van]

I was watching a bit of the Americas Cup coverage, and I noticed that the cup boats look like the hull shape is very simmilar to Bolger's wall-sided sharpie designs. I haven't seen any lines drawings of the Cup boats, but from the pictures I've seen, they look pretty much flat bottomed and wall sided, the only difference between those and Bolger's sharpies is the radius at the chine. I'll bet that the curve of the sides matches the bottom curve also. I've also noticed the flatt-top main sail, looks like a modernized gaff rig. That keel looks totally impractical for a cruising boat, however.

[Tom Lathrop]

Mark, Notice that these AC boats sail at great angles of heel even in light wind. I was guessing that the heel was between 30 and 40 degrees in 10 to 12 knots wind. The "Chine" almost becomes the keel and normal rules don't seem to apply. Those narrow beam boats have very low initial stability and they heel quickly and just stop at about the same heel angle because of enormous ballast ratio.

Then there are the AC rules that cause some awkward appearing shapes.

[Russ Manheimer]

I've often thought lately while watching the races that the ACC Rule needs to add a "beauty" line to the formula. Such as "At all times and from all viewpoints the sheer of the boat shall have a pleasing shape." Perhaps that would eliminate the ugly humps one sees when they are heeled.

One can dream.

It would be fun to see what Bolger could do within the strictures of the ACC Rule.

Russ

[Mark Van]

"It would be fun to see what Bolger could do within the strictures of the ACC Rule."

I don't think that will happen, this is from the preface of "The Folding Schooner."

"I can recommend the results of an oath I took, now a good many years ago, with my right hand raised and my left on a copy of Claud Worth's Yacht Cruising, never to read a rating rule."

[PVanderwaart]

When the last Cup was held in NA, designer John Welsford observed that the hull shapes are more than slightly similar to Bolger's Folding Schooner.

[Stiletto]

I've often thought that they looked like radius chine designs.

I wonder if they could figure out a means of flying a topsail.

[Russ Manheimer]

PV,

Perhaps it's turned out that the most effecient shape has matching profiles for the bottom and sides. Add a perfect foil, round off the chines and there's an IACC boat.....You know they sort of look like a Ray Hunt 110 on steroids.

Here's a study by a Swedish university in Goteborg (http://www.na.chalmers.se/~bathfiel/CYR/jinwoobaik.pdf) of the development of hull shapes in this class. Check out the shapes on pages 35 to 40. They look more like a streched out Presto sharpie shape

Grant,

When you look at the current mains on the ACC boats, the top'sl's already there. Just imagine the 45 degree batten as the gaff.

Russ

[Stiletto]

Yes Russ, I see what you mean.

[Todd Bradshaw]

I'd like to know what they're using to paint them? Waves splash up on their topsides, then run off and it doesn't even look like the hull is wet.

[Mark Van]

I think that I saw somewhere that one of the teams was penalized for using the wrong kind of paint.

[Stiletto]

I was wondering about the paint. At the last cup TNZ had sort of an eggshell finish as I recall, this time it seems to be a very high gloss.

[ahp]

Take a look at a "Star" boat, almost flat bottom and wall sides. They are ment to sail on their chins.

[Thad]

The present AC boats may have a harder turn of bilge (chine almost) but if you look at the lines of Ralph M. Munroe's Presto you will see a marked similarity.