[C320-list] Boat Speed

[Richard A. Walker]

Once More.

1. Calibrate the knot meter on a measured mile.  (It takes 3 passes)
2. Run a test with no wind, slack tide, constant load and no waves and you
will see that they will the same.

I have many friends in the predicted log "racing" of doing this in power
boat "racing" hey check their knot meter every "race".  There are m any
variables, wind, boat load, bottom cleanliness, pit log cleaning etc.


Cheers,
 
Dick Walker
C-320 (687) WindWalker II
740 Olive Ave.
Coronado, CA 92118-2136
619.435.8986-----Original Message-----
From: C320-List-bounces at catalina320.com
[mailto:C320-List-bounces at catalina320.com] On Behalf Of John Van Vessem
Sent: Thursday, April 27, 2006 6:56 PM
To: C320-List
Subject: Re: [C320-list] Boat Speed

Orlando, I'd like to meet you some day, you sound like a fun guy.
   
  John (Sojourn 645)

Orlando.Duran at AveryDennison.com wrote:
  Mine is fine, I average about 7kn in all wind speeds and I like that... 

Also, how come my knot meter and GPS don't sync? :)

cuba libre 2
--------------------------
Regards,
OD

Sent from my BlackBerry Wireless Handheld



----- Original Message -----
From: C320-List-bounces
Sent: 04/25/2006 02:56 PM
To: C320-List at catalina320.com
Subject: [C320-list] Boat Speed

All,

It occurs to me the many variations in reported boat speed is likely due to
variations in the speed sensor calibration, or lack thereof. The only
accurate way to calibrate the boat speed sensor is by timing multiple passes
ata a constant speed through a measured course in slack water and opposite
directions. Average the runs, calculate the speed and compare it to the
readout for a correction factor to enter into the display. The more and
longer the runs, the more accurate the calibration.

In my experience the speedo out of the box can be off as much as 25%. I
suspect most boat dealers don't make any effort to calibrate the instruments
before delivery and many skippers either don't know or don't bother. 

Walter
Selkie #887


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John Van Vessem
Sojourn 645
Vallejo Yacht Club
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