they tried running a hydrofoil between Seattle and Victoria years ago. They quit it because they kept wiping out foils on logs!
Andy Peregrine C&C 40 On Tue, Sep 24, 2013 at 5:44 PM, Steve Thomas <[email protected]> wrote: > ** > The Canadian navy once had a hydrofoil ship which would do better than 60 > knots, as did the Norwiegans. The U.S. navy had armed and > operational hydrofoil patrol vessels rated at 48 knots, just under the 50 > knot limit you mentioned. There must exist a body(s) of engineering data on > how to deal with cavitation issues. It can't all be classified. Can it? > Did the designers of the current AC boats just decide not to deal with the > cavitation issue, and deliberately choose to depend on rules limits for > safety? > > Steve Thomas > C&C27 MKIII > > -----Original Message----- > *From:* CnC-List [mailto:[email protected]]*On Behalf Of *Bill > Coleman > *Sent:* Tuesday, September 24, 2013 5:16 PM > *To:* [email protected] > *Subject:* Re: Stus-List America's Cup. > > I think it may be the best ever. **** > > I never could understand my friends jumping off the couch during football > games and yelling and jumping – **** > > Now I understand a little better. **** > > ** ** > > Clipped this interesting tidbit from Lirakis’s Blog – **** > > <<FROM SAILING ANARCHY:**** > > ** ** > > I cracked the books a bit and ran some numbers yesterday. I think I have a > good reason for the wind speed limit being set where it is. Wow was I > wrong. The boats ended up being faster than they predicted, i.e. the > designs were too good. :-) This put them dangerously close to putting the > foils into cavitation speeds (~50+) that could have lead to real control > problems.**** > > ** ** > > Basically they want to limit boat speed to under 50 knots to stay safely > out of foil cavitation speeds. The boats can sail over 2x wind speed and in > some ranges are close to or at 3x wind speed the TWS needed to keep them > below 50 knots is in the 22-24 knot range.**** > > ** ** > > The wind limit for safety was not a reaction to the Artemis disaster as I > assumed incorrectly. I had assumed the limit was for structural concerns > not an unforeseen design challenge.**** > > ** ** > > If they want higher wind speed limits they have to lose the foiling to > remove the “50 knot barrier” or they can lose the wing to reduce the top > speed of the boats to under 3x wind speed.**** > > ** ** > > If they want to keep the full foiling and hard wings they are stuck with a > low wind speed limit until they solve the cavitation issue. Sort of ironic > that the faster the boat is relative to wind speed the lower the safe wind > speed becomes. If indeed the wind limit was lowered due to concerns about > foil cavitation then they got it right and the engineering math supports it. > **** > > ** ** > > It is not about being pansies, or poor design, or reaction to the Artemis > disaster. It is about unforeseen design success.**** > > ** ** > > Stop bitching about the boats being too fragile to sail in 30+**** > > Start celebrating that they are too fast to sail in over 25.**** > > ** ** > > I’m surprised that none of the SA techies from AC33 had done the figures > to reach this conclusion.>>**** > > ** ** > > When the races are over, assuming these boats are toast anyway, they > should see what they would take (and do) in 25Kts + **** > > With water ambulances on hand, of course.**** > > ** ** > > Bill Coleman**** > > C&C 39 **** > > ** ** > > *From:* CnC-List [mailto:[email protected]] *On Behalf Of *Ken > Heaton > *Sent:* Tuesday, September 24, 2013 4:37 PM > *To:* cnc-list > *Subject:* Re: Stus-List America's Cup.**** > > ** ** > > I actually think this is the best America's cup in years. I'm following > this one every day and I haven't done that fir years, probably since the > early 1980's.**** > > ** ** > > There are others who seem to agree with me. Have a look at this article > in the Huffington Post:**** > > ** ** > > > http://www.huffingtonpost.com/christopher-caen/a-cup-of-caen-yelling-at-_b_3975975.html > **** > > ** ** > > Ken H.**** > > ** ** > > On 24 September 2013 15:51, Edd Schillay <[email protected]> wrote:**** > > Bev,**** > > ** ** > > The Cup racing has gone downhill to be sure -- both in the teams and the > boats, but it is fun to watch any boat go 40 knots. **** > > ** ** > > I do believe, however, the America's Cup is not named after our country, > but the boat "America". **** > > ** ** > > All the best,**** > > ** ** > > Edd**** > > ** ** > > ** ** > > Edd M. Schillay**** > > Starship Enterprise**** > > C&C 37+ | Sail No: NCC-1701-B**** > > City Island, NY **** > > Starship Enterprise's Captain's Log Website<http://enterpriseb.blogspot.com/> > **** > > ** ** > > On Sep 24, 2013, at 2:48 PM, Bev Parslow <[email protected]> wrote:**** > > ** ** > > I am confused. We have a boat sponsored from a country that last time I > used an atlas was in the Middle East. All participants being interviewed > seem to have an accent from the Southern Hemisphere. Rumour has it that in > fact we have only one American on board. If they win, it should be called > the American's Cup. This really is quite a farce. Why not a boat, built, > designed and made in that country, filled from citizens from there with > sponsorship from the state.**** > > _______________________________________________ > This List is provided by the C&C Photo Album > http://www.cncphotoalbum.com > [email protected]**** > > ** ** > > > _______________________________________________ > This List is provided by the C&C Photo Album > http://www.cncphotoalbum.com > [email protected]**** > > ** ** > > _______________________________________________ > This List is provided by the C&C Photo Album > http://www.cncphotoalbum.com > [email protected] > > -- Andrew Burton 61 W Narragansett Ave Newport, RI USA 02840 http://sites.google.com/site/andrewburtonyachtservices/ phone +401 965 5260
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