America's Cup: Some questions-Any answers?

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Some questions-Any answers?

Printed From: Yachts and Yachting Online
Category: Keelboat classes
Forum Name: America's Cup
Forum Discription: Your thoughts on challenges to win the 'Auld Mug'
URL: http://www.yachtsandyachting.com/forum/forum_posts.asp?TID=6430
Printed Date: 10 May 25 at 1:01pm
Software Version: Web Wiz Forums 9.665y - http://www.webwizforums.com

Topic: Some questions-Any answers?

Posted By: JMC_DK
Subject: Some questions-Any answers?
Date Posted: 10 Feb 10 at 11:38am

1. What is the pre-race maneuvering going to look like? Will there be any?
2. Does the design of the "boats " in any way change the objectives of the pre-race maneuvers.
3. Will it be a race to the layline, 1 tack and mark rounding?
4. How will the boats round the mark (I know, carefully)?
5. Will the down-wind angles be more/less acute than for monohulls?
6. How hard/easy is to jibe these boats in heavy wind, running down-wind. And finally:
7. How long will it take to sail the 2-3 required races?

Replies:

Posted By: Phil eltringham
Date Posted: 10 Feb 10 at 11:59am

In answer to question 7. At the current rate, about 5 years!

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FLAT IS FAST!
Shifts Happen

Posted By: ellistine
Date Posted: 10 Feb 10 at 1:01pm

I'm sure saw something on Eurosport about Oracle winning
the toss to allow them to start the race on Starboard. Does
that mean the Alinghi have to start on Port?

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Posted By: JMC_DK
Date Posted: 10 Feb 10 at 2:13pm

A coin toss! You have to be kidding! And what if the wind is expected to move in the opposite direction from this tack?

Or will one boat be so much easier to tack than the other, that it won't matter for the easy tacking boat.

I mean look at these things. They are square.

Posted By: Teamvmg
Date Posted: 10 Feb 10 at 2:24pm

one boat enters the prestart box on each tack - before the
start

Posted By: alstorer
Date Posted: 10 Feb 10 at 2:37pm

Normal match racing stuff, that.

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-_
Al

Posted By: Scooby_simon
Date Posted: 10 Feb 10 at 8:50pm

Originally posted by JMC_DK

A coin toss! You have to be kidding! And what if
the wind is expected to move in the opposite direction from this tack?
Or will one boat be so much easier to tack than the other, that it won't
matter for the easy tacking boat.I mean look at these things. They are
square.

Rumor is that USA17 can tack in it's boat length. The wing
makes these things very different

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Wanna learn to Ski - PM me..

Posted By: Contender443
Date Posted: 11 Feb 10 at 12:53pm

Originally posted by Teamvmg

one boat enters the prestart box on each tack - before the
start

Does that mean that the boat with starboard rights can stay out of the pre-start box and do one timed run on starboard so that it hits the line at tthe start gun. Or do they have to enter the pre-start box at 6 minutes to go?

Posted By: Laser 173312
Date Posted: 11 Feb 10 at 1:23pm

I know Alinghi tried a timed run on the practice course last week and arrived 10 second early. They lost 2 minutes in going back across the line. At the speed these things are travelling thats about a mile.

I can't see anyway that they'll try a dial up with Zillas.

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Posted By: Scooby_simon
Date Posted: 11 Feb 10 at 1:31pm

Originally posted by Laser 173312

I can't see anyway that they'll try a dial up with Zillas.

The dialup will be VERY different; I believe that they will not want to get into real close quarters in any real wind and it will be less about getting a foul on the oppo, but forcing them away from where the other wants to be; the change to the line/bouy setup is to (IMO) to keep them further apart and to discourage close in; head-to parking battles. I can see that we might see timed runs after some closer (but not close in team-racing terms) encounters; again; hitting the line too early at 30+ kts is a nightmare and as said getting back takes some time!

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Wanna learn to Ski - PM me..

Posted By: Scooby_simon
Date Posted: 11 Feb 10 at 1:37pm

regarding gybing angles; these will be fairly deep given the sppeds these are hitting in 10kts of wind (I've heard of 30kts in 8kts true!!!)

Re tacking upwid; again I think they will be similar to "normal" beach cats; a more stategic view of sailing up wind (hence all the stuff in remote wind sensing) whereby you decide where on the course you want to be for expected shifts and wind bends instead of the more simplictic "tack on the shift when it arrives" of "quick totack boats".

IF speeds are similar, and wind is stable, there might be some cover tacking but the stregic view of the 20 mile leg will probs override most of the time.

Mark rounding will be the same as other boats; bear-off carefully and smoothly and get the reacher up pronto!

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Wanna learn to Ski - PM me..

Posted By: JMC_DK
Date Posted: 12 Feb 10 at 11:20am

My bet is that they will stay out of each others way and start on the same tack pretty near the middle of the line and the primary objectives will be speed + not going over the line early.. That is the closest they will be for the entire two races

Posted By: tgruitt
Date Posted: 12 Feb 10 at 11:29am

Can anyone explain what a dialup is please? I'm guessing we're not talking about the type of slow internet?

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Needs to sail more...

Posted By: Isis
Date Posted: 12 Feb 10 at 6:42pm

The Dialup occurs when both boats aproach on oposite tacks (as they do entering the box prestart) and turn upwind as they reach each other - Dialling down would involve turning downwind.

Posted By: Steve411
Date Posted: 13 Feb 10 at 9:31am

Different subject - why is a solid sail so apparently more efficient than a conventional soft sail? (I'm thinking I should have paid more attention in physics lessons at school).

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Steve B
RS300 411

https://www.facebook.com/groups/55859303803" rel="nofollow - RS300 page

Posted By: PeterG
Date Posted: 13 Feb 10 at 10:00am

In large part it must be about control (though there must
also be advantages in having an airofoil whose curves
don't keep changing as the wind does). Oracle has a
series of flaps and a large number of sensors which
presumably mean that they can precisely control the shape
of different bits of the "sail" in ways that mortals with
a kicker, outhaul and cunningham can merely dream about.

Watching the start of the downwind leg yesterday what was
striking was how much more consistent Oracle's course and
heel were than Alignhi's. Partly that may be due to
Oracle being that much more powered up, but I don't mind
betting that part of it was due to the fine control they
could exercise on the wing as the wind strength
fluctuated.

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Peter
Ex Cont 707
Ex Laser 189635
DY 59

Posted By: lurker
Date Posted: 13 Feb 10 at 1:27pm

A number of things change at once in the change so hard to pin the benefits of- control of twist in seven stages
double surface aerofoil (likely to improve range of efficient wind angles)
smooth & solid aerofoil (likely to be important in pointing high)
the 'slot'(likely to be especially important downwind)

at times the difference appeared big, hardly ever looked like the Cat had a gust to itself. My uneducated guess is that the slot is the crucial factor in the mix. (The idea is to prevent the airflow detaching). I wonder if a 'two part' sail could be fabricated to do similarly, maybe with straps holding the two parts.