"Harry Krause" wrote in message
...
Lloyd Sumpter wrote:

On Wed, 21 Jan 2004 18:54:21 +0000, Harry Krause wrote:

Lloyd Sumpter wrote:

Hi,

I still have the thru-hull from a long-dead knotmeter in Far Cove.
I
may be able to dig up the partially-working paddle-wheel sender (iirc
needs a
new paddlewheel).

Can I get a new sender, with proper documentation so I know how it
works, and hook it into my laptop? The Signet sender appears to put
out a
voltage more-or-less proportional to speed, correct? So I would need a
bit of
electronics (buffer/amp? and A/D) to put the value into the parallel
port of
the laptop. Then a few runs with a GPS in still water should allow me
to
calibrate it.

Where can I get data on what these senders actually put out?

Lloyd Sumpter
"Far Cove" Catalina 36 - waiting for new engine


Sheesh, Lloyd, why don't you plumb that through-hull and add something
useful,
like a baitwell?

Knotmeter...whyfor? You have a main GPS working of your mains, and a
backup GPS
that works off its own little batteries, right?

Just interface one of the GPS units with your laptop.

Already done that with the backup GPS.

You wouldn't know this sitting in your armchair, but in the Actual
Ocean, there
are currents, waves, etc. which make the "speed over ground" calculated
by the
GPS not the same as "speed through the water", which is what a knotmeter
shows.
Now, for 50 points and what's behind Door #2: When testing a new engine
for
performance, which speed value should you use? (cue Annoying Jeopardy
Waiting
Music...)

Lloyd Sumpter
"Far Cove" Catalina 36


Ocean? No offense, but I thought you sorta wandered a 100 miles or so
from your home marina.



--
Email sent to is never read.

He's closer to the ocean than you. A hundred miles from his home marina
could put him about 90 miles into the Pacific past Vancouver Island. And
Vancouver Island is in the Pacific.