In article ,
wrote:

I wonder what would the best way to calibrate a depth sounder.
From what I read most depth sounders default setting are calibrated from
the transducer to the sea bed.
Other prefer to adjust the setting to the water line to the bottom of the
sea or from the bottom of the keel.
I wonder what is the preferred method of calibrating?

My depth sounder is one foot bellow the water line. This gives me a good
reference to the water levels printed on the chart plus the proverbial
pilot foot.

Have fun