Instrument depth calibration

Calibrate your instrument depth transducer as follows.

Select either:

Below keel — The depth reading will be decreased from the transducer’s default reading by the offset value you specify. The offset should be the distance between the transducer and the bottom of the keel.
Below waterline — The depth reading will be increased from the transducer’s default reading by the offset value you specify. The offset should be the distance between the waterline and the transducer.
Below transducer — This is the transducer’s default reading; no offset is required.