Raymarine ST40 Depth Instrument Owner's Handbook Manual page 33

Chapter 4: Calibration
Depth
units
Depth
offset
WARNING:
Correct offset values are essential to ensure
the safe operation of the vessel. If you are
not sure how to set the correct values, refer
to the additional information given in text.
To save your settings and return to normal operation from any screen,
hold down
USER CALIBRATION
During normal operation
hold down and
for approximately 2 seconds
Entry
screen
Depth
response
CAL
FA
M
CAL
and for approximately 2 seconds
Note:
If there is no key activity when the Entry screen
is displayed, calibration will time out to normal
operation after 5 seconds,
15 (fast)
CAL
1 (slow)
Shallow alarm
lock
CAL
D4662-2
25