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Member Since 29 May 2007
Offline Last Active Feb 05 2016 06:38 PM

Posts I've Made

In Topic: ACWS Bermuda - Oct 16-18

03 November 2015 - 05:31 PM

Oh yes, the slot. Thank you. Which was to control fore/aft COE?
There was a lot of talk about loading up the rudder. I interpreted that as shifting COE aft to increase wx helm. Was that correct?

In Topic: ACWS Bermuda - Oct 16-18

03 November 2015 - 05:03 AM

You have mentioned several times in the past that OR copied NZ which allowed them to win . If the boats are copies then how did OR become so much faster ? If the boats are so similar then the crew of one is obviously better than the other or do you have another conspiracy theory ?

It was not so much that the crew were better rather .. after losing the early races .. they finally accepted that the designers knew what they were talking about and started sailing the boat as instructed .. the mast was raked back and sailing to windward with sheets slightly eased made it possible to foil to windward and that made the difference .
Hmmm, I remember differently: that after losing sailing how the designers told them they should, they finally did what the sailors had wanted... rake back, increase wx helm, and foot for speed. Am I wrong?

In Topic: ACWS Bermuda - Oct 16-18

03 November 2015 - 12:18 AM

The weird thing about platform pitch is that platforms could have different pitch but the same foil pitch in the water, because of the foil pitch between the boats being set differently.

The default pitch (degree of nose-down appropriate for the expected race conditions) of the ac45fs is preset using the rudders.
Get that wrong, i.e. drive the bows too low for the actual conditions with the rudder preset and then have to correct by using an aggressive main foil angle and you'll be slow - but none of that will show in the data sets you've put together so far.
Can these 45's rake wing fore/aft while racing or between races?
Cause if not, rudder foil pitch adjustment is effectively wing rake, changing center of effort...potentially more significant than hull trim.

In Topic: ACWS Bermuda - Oct 16-18

31 October 2015 - 07:53 PM

If anyone is curious, I set up a little database using the metrics that ACRM supplies gratis that can answer a lot of Q's about performance in the Bermuda races; by Race, Leg, Upwind or Down, heading sailed, Port or Starboard tack, speed, angle off the wind, pitch, heel, and by Team.

Am not willing to screw around too much with Excel charts but am happy to provide data sets if anyone else would like to have some fun with it. There are a few 'Radar' chart styles in Excel that could be good for plotting polars, for raw speed or for VMG and/or for VMC.

Compared to the standard examples that I've seen on the web for your typical OD monohull, even the crude Polar attempts that I have tried suggest these that even these AC45F's are just off the freaking charts.

We should totally resurrect the bad science thread.

In Topic: ACWS Gothenburg - August 27

30 August 2015 - 12:45 AM

@nav, what's your definition of 'high visibility color'? Cause yellow, red, and silver all seem decent candidates too me?