America's Cup

[Stephen Ditmore]

Yades:

I was rooting for One World in 2003. Now that our teams have combined and my other favorite, Mascalzone Latino, has been eliminated, I'm with you.

Luna Rossa all the way!

One point that's interesting to me about America's Cup hull design: let's say you're optimizing your boat for 13 knots, but you also want to be fast at other windspeeds.

• One option is to optimize each variable, such as Cp and ratio of stability/wetted surface, for 13 knots. Let's call this version A.
  
• Another option is to design a boat that has a higher Cp than version A for windy/fast conditions, and less wetted surface for light conditions. We'll dub this version B.

I think there's some evidence that version B is likely to be the better ACC raceboat. Is that your take?

[Guillermo]

Desafío Español lost....
....but we're still on the move...!

Well done, Luna Rossa!

[lazeyjack]

yes but you are not getting a thrashing, I,m still with you)

[Guillermo]

Thanks, Stu, but we lost again. Only one left to leave....

[yades]

Originally Posted by Stephen Ditmore

Yades:

I was rooting for One World in 2003. Now that our teams have combined and my other favorite, Mascalzone Latino, has been eliminated, I'm with you.

Luna Rossa all the way!

One point that's interesting to me about America's Cup hull design: let's say you're optimizing your boat for 13 knots, but you also want to be fast at other windspeeds.

• One option is to optimize each variable, such as Cp and ratio of stability/wetted surface, for 13 knots. Let's call this version A.
  
• Another option is to design a boat that has a higher Cp than version A for windy/fast conditions, and less wetted surface for light conditions. We'll dub this version B.

I think there's some evidence that version B is likely to be the better ACC raceboat. Is that your take?

I personally believe version A being more adequate (they are racing under prevailing wind conditions mainly around 9 to 11 knots. (I will soon post a new thread with lines plan and hydrost. calc for an ACC canoe body in line with the latest trends, just for general discussion/speculation with the community). It could be of somewhat interest (....maybe...).
The basic design criteria of the canoe body being as follows:

- Design Velocity Ratio=1.60 to 1.62
- Prevailing wind speeds 7 to 10,5 kts (force 3 Beauf.)
- Hull Vmax =12,35 kts
- Designed yacht speed =8,5 to 9,5 kts (70 to 78 % Vmax)
- Designed TQ =1,10 to 1,24
- Corresponding FN = 0,33 to 0,37
- Corresponding optimum Cp range (canoe body only) 0,535 to 0,576
(here I'd preferred to mantain the Cp towards 0,535...- version A as
you outlined -)
- BWL/LWL ratio the minimum as possible = 0,20 giving BWL=3,60 m. ca.
- Extreme U transverse hull sections leading towards Cm values in excess of O,90.
- On the above basis Tc (canoe body draft) seems somewhat reasonable
around 0,710 (Tc=(Displ/(LWL*BWL*Cp*Cm))
- From which an approx idea of (WSA) Wetted Surface Area - canoe body
only - seams reasonable being around 55 to 57 sq. m. a very good starting
point indeed.
- Ending with a ratio SA(Sail Area)/WSA = 5,80 ca. !!! ..."star wars"... values
existing only for the ACC Yachts !!!.....

These are the basic concepts behind the hull lines (..to my very personal opinion.....)

By the way....I was forgetting.....unbelievable job made by J. Spithill (!!!) on todays 5th race. A real pain...for BMW ORACLE crew....I wouldn't dear being at C. Dicksons's place @ this very moment...not even for one second..!!!!

[Guillermo]

Thanks for your interesting post, yades. Some discussion about AC yachts design criteria and rules has already been done in this and other threads, but I support your idea of opening a devoted one to discuss hull lines, hydros, etc.
Cheers.

[lazeyjack]

I cant see Barker being able to control Spittall, if indeed it comes to team nz and Luna Rossa
By this time BMW/O and Dickson must be dreading the starts

[Vega]

Luna Rossa raced beautifully today.. It seems the Americans are in a tight spot. They need 4 wins in a row to beat the Italians. A week ago who would have guessed these results?

[Roly]

SpitHill's luck is about to run out...........law of averages....
He might have sized up Dicksons fiery temperament & force errors.
But it ain't the same against Barker.(If it eventuates)
There seems to be inflexibility in the BMO camp.Scant contingencies in place.
Perhaps Oracle is just a dog in the box,slow to turn & slow to accelerate.
Seems they could have gotten out of several of the scenarios with quicker communication/crew understanding on what they were trying to achieve.
WE will see if the stats remain the same.....ie 93% winner are
1st to topmark.Gotta read the pressure/shifts; this seems to be having more effect as the series progresses.
What if....I'm talking myself into a abyss here........

[lazeyjack]

Originally Posted by Roly

Spittall's luck is about to run out...........law of averages....
He might have sized up Dicksons fiery temperament & force errors.
But it ain't the same against Barker.(If it eventuates)
There seems to be inflexibility in the BMO camp.Scant contingencies in place.
Perhaps Oracle is just a dog in the box,slow to turn & slow to accelerate.
Seems they could have gotten out of several of the scenarios with quicker communication/crew understanding on what they were trying to achieve.
WE will see if the stats remain the same.....ie 93% winner are
1st to topmark.Gotta read the pressure/shifts; this seems to be having more effect as the series progresses.
What if....I'm talking myself into a abyss here........

well you have good and free coverage there, here we get NONE ZILCH for free, so I cant see whats going down, , maybe there is a live website somewhere?

[charmc]

Originally Posted by lazeyjack

well you have good and free coverage there, here we get NONE ZILCH for free, so I cant see whats going down, , maybe there is a live website somewhere?

LJ,

This is the best web coverage, I think:

http://www.americascup.com/en/

[Roly]

L/J
Try this from SA.

http://www.sailinganarchy.com/forums...howtopic=53781

Might have to tweak around abit.
Haven't played with it as we are live TV and I cannot risk my OS with dodgy
downloads.Too busy workin & boatbuildin to fix a crash.

[Vega]

Originally Posted by lazeyjack

well you have good and free coverage there, here we get NONE ZILCH for free, so I cant see whats going down, , maybe there is a live website somewhere?

Lazey, here you can see small movies from every race:


http://www.americascupanywhere.com/internet_tv/

Click on "on demand" to see what you want to see.

[Vega]

Surprise, surprise, the American team was wipped out and the Spanish won another time. Congratulations to Desafio Español .
For the huge difference in budget between the American team and the others we would expect a better performance. What a waste of money

[Guillermo]

Does that mean our team and boat are better than the American...?
Desafío will not get defeated that easy! Go for them boys! Nothing is lost yet!