America's Cup conundrum

I read that there is no agreement among the teams about the use of hydrofoils on the 72-foot cats that will race for the America's Cup. I find this counter-intuitive; I'd think that foiling and getting the hulls out of the water would reduce drag significantly and be much faster. Apparently leeway is a factor, however, and perhaps the velocity made good (VMG) towards the mark is better when you have the leeward hull to push against. My boat only has one hull, and does not use a rigid wing for a sail. It's likely worth less than half as much as a single winch on an AC72 and the only way it could match the speed of those boats would be if you dropped it from a crane, but I still find the science and boat design of the AC competition to be fascinating. It pushes the boundary conditions of our sport and reveals some breath-taking performance. I think this is going to be great fun! Alfred Poor 1973 Tartan 34C #288 "Jambalaya"

While I agree it is going to be great, I also enjoyed the Doytona-500 this year and I think they are both have about the same degree of relevance to my kind of sailing. Allen On Wed, Feb 27, 2013 at 7:04 AM, Alfred Poor <ap… [at] verizon.net> wrote: > ** > > > I read that there is no agreement among the teams about the use of > hydrofoils on the 72-foot cats that will race for the America’s Cup. I find > this counter-intuitive; I’d think that foiling and getting the hulls out of > the water would reduce drag significantly and be much faster. Apparently > leeway is a factor, however, and perhaps the velocity made good (VMG) > towards the mark is better when you have the leeward hull to push against. > **** > > ** ** > > My boat only has one hull, and does not use a rigid wing for a sail. It’s > likely worth less than half as much as a single winch on an AC72 and the > only way it could match the speed of those boats would be if you dropped it > from a crane, but I still find the science and boat design of the AC > competition to be fascinating. It pushes the boundary conditions of our > sport and reveals some breath-taking performance.**** > > ** ** > > I think this is going to be great fun!**** > > ** ** > > Alfred Poor**** > > 1973 Tartan 34C #288 “Jambalaya”**** > > ** ** > > >

"Apparently leeway is a factor, however, and perhaps the velocity made good (VMG) towards the mark is better when you have the leeward hull to push against." I would still think that you'd want to get the hull out of the water with the hydrofoil and then combat leeway with a vertical fin below the horizontal hydrofoil. Actually, I remember seeing a circular shaped hydrofoil that keeps it's lift as the boat heels, and a *small *vertical fin. I was surprised at how small it was. Did I see that picture on this list? I'm sure a great deal of engineering also goes into building stability into the system... A heeled cat, resting on a hydrofoil or two, and at high speed. Oh my.. fun :) On Wed, Feb 27, 2013 at 7:30 AM, Allen Edwards <al… [at] gmail.com>wrote: > ** > > > While I agree it is going to be great, I also enjoyed the Doytona-500 this > year and I think they are both have about the same degree of relevance to > my kind of sailing. > > Allen > > > On Wed, Feb 27, 2013 at 7:04 AM, Alfred Poor <ap… [at] verizon.net> wrote: > >> ** >> >> >> I read that there is no agreement among the teams about the use of >> hydrofoils on the 72-foot cats that will race for the America’s Cup. I find >> this counter-intuitive; I’d think that foiling and getting the hulls out of >> the water would reduce drag significantly and be much faster. Apparently >> leeway is a factor, however, and perhaps the velocity made good (VMG) >> towards the mark is better when you have the leeward hull to push against. >> **** >> >> ** ** >> >> My boat only has one hull, and does not use a rigid wing for a sail. It’s >> likely worth less than half as much as a single winch on an AC72 and the >> only way it could match the speed of those boats would be if you dropped it >> from a crane, but I still find the science and boat design of the AC >> competition to be fascinating. It pushes the boundary conditions of our >> sport and reveals some breath-taking performance.**** >> >> ** ** >> >> I think this is going to be great fun!**** >> >> ** ** >> >> Alfred Poor**** >> >> 1973 Tartan 34C #288 “Jambalaya”**** >> >> ** ** >> >> > >

On 2/27/2013 10:04 AM, Alfred Poor wrote: > > > I read that there is no agreement among the teams about the use of > hydrofoils on the 72-foot cats that will race for the America's Cup. I > find this counter-intuitive; I'd think that foiling and getting the > hulls out of the water would reduce drag significantly and be much > faster. Apparently leeway is a factor, however, and perhaps the > velocity made good (VMG) towards the mark is better when you have the > leeward hull to push against. > > My boat only has one hull, and does not use a rigid wing for a sail. > It's likely worth less than half as much as a single winch on an AC72 > and the only way it could match the speed of those boats would be if > you dropped it from a crane, but I still find the science and boat > design of the AC competition to be fascinating. It pushes the boundary > conditions of our sport and reveals some breath-taking performance. > I agree that it's beneficial to advance the science of boat design and push boundaries, but it's important to establish parameters, too. One limiting factor for real-world sailing has always been seaworthiness--the ability of the vessel to survive in a reasonable range of conditions. When the boats can only function in a very narrow range of wind and seas, they become too purely theoretical to be interesting. It seems to me that both science and sport would be well served by a requirement that the boats be raced in whatever conditions appear, within a reasonable range (there are some conditions that none of us would head out in, by reason of good judgment and reasonable concern for safety of crew). I want new boats to be fast, sexy, and sophisticated but I don't want them to be delicate and dysfunctional. As I recall, the original /America/ crossed the Atlantic on her own bottom. Perhaps that's too much to ask for racing boats now, but at least we should expect them to be seaworthy. The schooner /Brilliant/, certainly the most aptly named boat, set a record for yachts of her size on her initial voyage across the Atlantic. Walter Barnum had the record, with departure and arrival times, memorialized on a bronze plaque in her companionway. It wouldn't be realistic to expect AC yachts to be sailing and in fine form 70 years later, but we ought at least to expect that they will perform /as sailboats/. One aspect of life as a sailboat is surviving the anticipated environment. Chris Campbell > >