RE: MPH Readings and relative speed

From: Sayer, Chris (ChrisSayer@StratfordGroup.com)
Date: Thu Feb 17 2000 - 19:46:53 PST


I have found the GPS useful even despite the frame of reference problems.
Making changes to trim, heeling angle, weight distribution while on a given
tack still makes a difference detectable on GPS. If I gain a quarter or half
a knot, I know it. I can see what works and what doesn't. I may not know
whether I am really doing 3.75 knots or 4.25 knots, but since I don't know
the wind or current with equal precision, that number would not be much use
to me anyway.
 
Chris Sayer
P15 #2380, Akala
San Jose, CA

-----Original Message-----
From: Rye Gewalt [mailto:ryeg@vais.net]
Sent: Thursday, February 17, 2000 5:44 PM
To: Potter List; Dickerson, Richard
Subject: MPH Readings and relative speed

Richard Wrote.....

One problem with any of the impeller driven systems is that all of them
measure your speed in relationship to the water.

That's just the problem! I guess it's sort of a frame of reference thing,
but I'm interested in how well my boat is performing with relation to the
water, not how fast I am going to get somewhere. On the Potomac where I
sail I have frequently found my boat splashing along merrily through the
water with no change in the shore line scenery due to an oncoming current.
I'm just interested in how well I am setting up the boat. If I were
interested in knowing how quickly I was gonna get somewhere, I'd drive.

The above frame of reference problem is exactly what is keeping me from
allowing myself to buy a GPS -- something that the little kid in me really
wants!

We sail with the Tide! or maybe against it....I dunno; just so we sail!

Regards
Rye

PS Years ago I had a friend hover in an old Aironca (SP)Champ airplane over
the grass field airport by flying into a strong head wind. Kids do the
damnedest things....



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