[Rhodes22-list] Knotstick

[Michael D. Weisner]

Ron,

We used two devices that measure "water speed" (not "velocity made good" as 
gps does.)  One was a tube with a ball in it that needed to be immersed and 
held perfectly vertical - a real pain and very hard to read hanging over the 
side, near the water.  The second one was basically a fish scale and a small 
sea anchor that was dragged behind the boat.  The effective speed (including 
current) was proportional to the reading on the fish scale (1/2oz per knot 
or something like that.)  I found it easy to read but difficult to calibrate 
(or keep in calibration.)

There is now a commerical version available that may have solved the cal 
problems (www.knotstick.com) for $46!  Just be sure that the drag line stays 
clear of the prop (put it on the starboard side) and keep the disc clean; 
seaweed and debris must be removed for proper operation.  Also, the location 
of the drag line is important to the reading; the line should be in the 
smooth flow outside of the turbulent wake for accurate readings.

Mike
s/v Shanghai'd Summer ('81)
Nissequogue River, NY

From: "Ron Singerman" <sail at tds.net> Tuesday, January 22, 2008 11:46 AM
> Has anyone any experience with using a Knotstick?  Opinion?
>
>>>ron<<
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