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zirtaeb



Joined: 03 Jul 2009
Posts: 2325

PostPosted: Wed Aug 29, 2012 4:15 pm    Post subject: Reply with quote

I DO understand the need for the longest waterline possible in a 45'er, to increase pointing and speed, but why at such a huge expense of pitchpoling?
The boats can handle 25mph winds, IF the bow don't bury! BUT, the bow does bury. They can easily produced a variable pitch horizontal wing atop the bow, the the boats would be able to sail after 1PM safely.
Notice also, when heading upwind, the dagger/centerboards are barely down at all, and mostly up on the downwind reaches. I know the designs are for "5-15mph winds, but why be so rigid, when Crissy is throwing you 14-25mph winds most PM's?
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tony



Joined: 05 May 1994
Posts: 60

PostPosted: Wed Aug 29, 2012 11:03 pm    Post subject: Reply with quote

andydavis wrote:

yeah, but clearly offset by the speed loss to capsize, or throttling back to avoid it.

I agree that pitchpoling is not conducive to optimum speed but I'm not at all sure that throttling back is necessary in order to avoid it. Burying the bow, even a little, will tend to slow you down. A skilled helmsman will bury the bow less often and by smaller amounts than an unskilled one, resulting in both increased speed and less danger of a crash. The key question is whether the design is such that the best helmsmen are sufficiently skilled to avoid crashes for the expected conditions at the various race sites for the AC45s around the world. And I have no idea whether the 72s are more crash-prone or less than the 45s: maybe the larger size and the increased moment of inertia allows just a little more reaction time and reduces the problem. Or maybe not.
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jfloviou



Joined: 30 Aug 2012
Posts: 1

PostPosted: Thu Aug 30, 2012 4:30 am    Post subject: Reply with quote

damel wrote:
Team Oracle - S gave Korea room around the mark and then as leward boat had right of way to head them up (closer to the wind). Oracle then tried to head korea up: Korea gave way the first time but the second time they held their course towards the bottom of the finish line to try and power reach over the top. Oracle still had overlap however and was forced to point below the finish. So as windward boat Korea was supposed to keep clear of Oracle and didn't. There is a replay from the boats out there that shows it well but from the aerial shots you can't see it at all.


Well, something crucial misses here: the Sailing Rules are modified for AC 45!

How the overlap has been established (from clear astern or not) has no more impact on the right to go higher than his proper course. Rules are only:

ON THE SAME TACK, OVERLAPPED
When yachts are on the same tack and overlapped, a windward yacht shall keep clear of a
leeward yacht.
12 ON THE SAME TACK, NOT OVERLAPPED
When yachts are on the same tack and not overlapped, a yacht clear astern shall keep
clear of a yacht clear ahead.

=> in other race than AC45, Spithill would have been penalized for sailing higher than his proper course after establishing an overlap from clear astern.

This critical change from our day to day way of racing clearly explains why Nathan O. was surprised: he is not used to this special rule.
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andydavis



Joined: 11 Apr 1999
Posts: 264
Location: Point Isabel

PostPosted: Thu Aug 30, 2012 11:40 am    Post subject: Reply with quote

tony wrote:

...A skilled helmsman will bury the bow less often and by smaller amounts than an unskilled one...


Oh yeah okay, I see what you're talking about...like Ben Ainslie, Loïck Peyron, Russell Coutts, Jimmy Spithill, etc.
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tony



Joined: 05 May 1994
Posts: 60

PostPosted: Sat Sep 01, 2012 9:21 am    Post subject: Reply with quote

andydavis wrote:
tony wrote:

...A skilled helmsman will bury the bow less often and by smaller amounts than an unskilled one...


Oh yeah okay, I see what you're talking about...like Ben Ainslie, Loïck Peyron, Russell Coutts, Jimmy Spithill, etc.


Funny. Well, to the degree that sarcasm is ever funny.

Yes, world-class sailors all. But they still needed to become skilled at driving the AC 45s. Here's something Ainslie said recently in his blog:

Today was the last day of practice before the opening 2012/13 AC World Series kicks off here in San Francisco.

Whichever way you look at it we are playing catch up, but there’s no surprise in that. There are some hugely experienced people in this class who have been sailing these wing masted cats in all kinds of conditions so we will have our work cut out to get up to speed. They’re technical, powerful boats and in the classic, breezy San Francisco conditions they can bite you pretty quickly so there’s plenty to learn.
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