![](/images/new-backgrounds/1303431/30343113x1.webp)
3-4 Anchor watch
To set an anchor watch, set the too shallow alarm to slightly less than the current depth and set the too deep alarm to slightly more than the current depth. Allow for tide changes.
3-5 Set keel offset
Keel offset is described above. The range is ± 2.9 m (± 9.6 ft, ± 1.6 fathoms):
1Press +
to display the Keel Offset screen.
2Press or
to change the keel offset.
3Press .
Keel offset (negative)
4 Systems of several instruments
Several Northstar instruments can be connected together to share data. There are two ways of connecting instruments together, NavBus or NMEA.
4-1 NavBus
NavBus is a Northstar proprietary system that allows systems of multiple instruments to be built using
a single set of transducers. When instruments are connected by NavBus:
If you change the units, alarms or calibration in one instrument, then the values will automatically change in all other instruments of the same type
Each instrument can be assigned to a group of instruments (see section
If an alarm sounds, mute it by pressing on any instrument which can display that alarm.
NavBus and the Explorer D310
If the Explorer D310 does not have a depth transducer fitted then the unit will automatically take depth readings from another instrument, via NavBus, if the data is available. For more information, refer to the NavBus Installation and Operation manual.
Note: If a transducer is not fitted to the unit and the corresponding external data is not available then the displayed value will be dashes (—
4-2 NMEA
NMEA is an industry standard, but is not as flexible as NavBus as it requires dedicated connections between instruments. Depth data is output by the Explorer D310 and can be read and displayed by the Northstar Explorer R310 or other NMEA instrument.
Northstar Explorer D310 Installation and Operation Manual | 7 |