Slower Downwind?

Sayer, Chris (ChrisSayer@StratfordGroup.com)
Wed, 10 Nov 1999 11:52:44 -0500

- - - - - - - - - - - - - - - - - - - - - - - - - - -
West Wight Potter Website at URL
http://www.lesbois.com/wwpotter/
- - - - - - - - - - - - - - - - - - - - - - - - - - -
Judging by the gaggle of us toward the back of the pack, the P15 didn't seem
to have trouble downwind, at least compared to the M15. I rounded the upwind
mark about 50 yards behind an M15, and was maybe 75-100 yards ahead at the
leeward buoy. The other blue P15 in our group kept almost exactly the same
relative position to us the entire downwind leg. The Compac 16 had been in
our vicinity at the upwind mark, but ran away from us downwind. (He had a
genoa and whisker pole, unlike the rest of us.) It seemed like we were also
faster to windward, but my tacking skills weren't very sharp Saturday, so I
squandered the chance to move up very far.

Thanks for setting up a fun event, Judy!

Chris Sayer
P15, #2380, Akala
-----Original Message-----
From: JBlumhorst@aol.com [mailto:JBlumhorst@aol.com]
Sent: Tuesday, November 09, 1999 9:27 PM
To: wwpotter@tscnet.com
Subject: Re: p15 results cruiser challenge

- - - - - - - - - - - - - - - - - - - - - - - - - - -
West Wight Potter Website at URL
http://www.lesbois.com/wwpotter/
- - - - - - - - - - - - - - - - - - - - - - - - - - -
In a message dated 11/9/99 9:13:35 PM Pacific Standard Time, chrdvd@gte.net
writes:

> So was the reason the Montgomery 15 won due to it having a 125% Genoa
> compared to the 50% storm jibs of the p15's. I noticed for the big boat
race
> that Jerry won using a 110% Lapper over an Mont.17 and P19 with 150%
> Genoa's. How would inquisitive minds come to a conclusion regarding these
> descrepidating (that word almost broke my spellchecker) facts!
>
> Dave L

Hi Dave,

Maybe, but maybe not. The Monty 15 is three hundred pounds heavier than
the
Potter 15. Even with the small 23 foot jib, the P15 has a "sail area
to Displacement" ratio of about 0.18, while the M15 has an SA/Disp of about

0.13.

I think it's clear that the P15 was much faster upwind than the M15, but
much
slower downwind.

Take a look at these two items:

My page on the modern "hull speed" equation at <A
HREF="http://members.aol.com/jblumhorst/hullspeed.html">How Fast IS a West
Wight Potter? A New Look at Hull Speed.</A>

My post on the race and the various sail areas, displacements, LWL's at <A
HREF="http://www.cruisecortez.com/webbbs/trailersailor/index.cgi?read=38834"
>R
e: Sail area, LWL, displacement</A>

Best,
Judy