Well sensible people may have the privilege of sailing in deeper waters than
here on the East Coast. At low water, there is frequently about 1.5m and
most of us, reluctantly have to scrape along with 0.1m under the keel if we
are lucky. Added to that there are a number of us who are always sailing on
each others boats, and it is nice to know if the echo sounder says 0.2m,
regardless of which boat you are on, that is what you have got under you.
I take your point about anchoring, but I guess we drop the anchor once for
every 20 or 30 times we are scraping the bottom.

Phil

"Glen "Wiley" Wilson" wrote in
message ...
On Mon, 4 Apr 2005 23:50:24 +0100, "Phil Stanton"
wrote:

Does anyone know if there is a depth sounder which shows a negative depth.
OK sounds like a loony question.
I have a lift keel boat and want to set the offset when there is no water
under the keel with the keel down. Same as all sensible people with fixed
keel boats. Easy to do with my Raymarine ST60 Tridata echo sounder. Now if
I
raise the keel to go into shallower waters, there isn't 7 ft (2.2m) of
water
in a lot of places on the East Coast of England, I still want to know how
much water there is underneath me. Hence I need to find an echo sounder
that
shows 0.0m with no water under the keel when down, an say -0.7m when the
depth is 0.7m less than with the keel fully down.
Hence my question. I should have thought with the number of lift keel
boats
there would be a reasonable demand, and lets face it, it isn't rocket
science to make a minus sign show up on a LCD display

A lot of "sensible" people I know would set the offset so the unit
reads actual depth, which incidentally corresponds to the numbers on
the charts, providing an additional navigational check. These same
sensible people seem to have no trouble remembering how much water
they draw. Weird, I know. :-)

Glen
__________________________________________________ __________
Glen "Wiley" Wilson usenet1 SPAMNIX at world wide wiley dot com
To reply, lose the capitals and do the obvious.

Take a look at cpRepeater, my NMEA data integrator, repeater, and
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On Tue, 5 Apr 2005 09:45:11 +0100, "Phil Stanton"
wrote:

Well sensible people may have the privilege of sailing in deeper waters than
here on the East Coast. At low water, there is frequently about 1.5m and
most of us, reluctantly have to scrape along with 0.1m under the keel if we
are lucky.

Interesting theory, but I'm on Florida's Gulf coast. Water is pretty
skinny here. Anything over 4 feet is considered deep draft.


Added to that there are a number of us who are always sailing on
each others boats, and it is nice to know if the echo sounder says 0.2m,
regardless of which boat you are on, that is what you have got under you.

And having your sounder read negative numbers helps this how? Since
this is a problem, maybe you should just stencil your draft on your
bulkheads in fluorescent chartreuse numbers to help each other out.
:-)

I take your point about anchoring, but I guess we drop the anchor once for
every 20 or 30 times we are scraping the bottom.

Hope you find what you're looking for.

Phil

__________________________________________________ __________
Glen "Wiley" Wilson usenet1 SPAMNIX at world wide wiley dot com
To reply, lose the capitals and do the obvious.

Take a look at cpRepeater, my NMEA data integrator, repeater, and
logger at http://www.worldwidewiley.com/