CORRECT CRAFT Nautique 220 Owner's Manual page 102

Controls and Indicators
keel offset. Pressing L and M will change the keel-offset setting.
Keel Display
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Holding M in for two seconds will save the new keel offset setting
and change the display back to the normal depth mode. The keel
offset is normally a negative number.
Units
Change the unit of measure.
This display will show "UNIT FT" for feet (default), "UNIT FA" for
fathoms, or "UNIT M" for meters. Pressing L and M will cycle
through the choices. Pressing and holding the M will save the units
shown in the display and change the display back to the normal
depth mode.
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