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
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