1. OPERATIONAL OVERVIEW
1-20
*
1
: Set and drift may be required to display [LOG (BT)] correctly in deep waters.
To change set and drift, see section 3.14.
*
2
: Where [ECDIS] is selected as the speed source, [4 OWN SHIP POSN] in the
[OWN SHIP INFO] menu is automatically set to [ECDIS] also. See section 1.13.
7. If you selected [MANUAL] as the speed data source, see section 1.12.2 to set the
speed.
8. Close the menu.
Notes on speed input
It should be noted that in determining a target's aspect by radar, the calculation of its
true track is dependent on the choice and accuracy of the own ship's course and
speed input. A ground-stabilized target plot may accurately calculate the ground track
of the target, but the target's heading may be significantly different from its track when
experiencing set, drift or leeway. Similarly, a sea stabilized target plot may be inaccu-
rate when own ship and the target, are experiencing different rates of set, drift or lee-
way.
• IMO Resolution A.823(19) for TT recommends that a speed log to be interfaced with
a TT should be capable of providing through-the-water speed (forward speed).
• Be sure not to select a [LOG] option when a speed log is not connected. If the log
signal is not provided, the ship speed readout at the top of the screen will be blank.
In the event of a log error, enter speed manually.
• If a speed log is selected as the data source and there is no signal present for 30
seconds, the [SPD] is shown as "*.* kn" and the label "LOST LOG(BT) SIG" or
"LOST LOG(WT) SIG" in yellow-orange appears and the alert buzzer sounds.
• When the speed input in use is interrupted or lost, the system automatically chang-
es to another speed input (stabilization reference) and shows the "SPD SOURCE
CHG" indication.
• On IMO-type radars with AIS in use, [MANUAL] and [REF] are shown in gray to in-
dicate they are not available for selection.
• A single-axis water log cannot measure speed when the wind is coming from the
leeway direction.
• When [ECDIS] is selected as the speed data source and communication with the
ECDIS is interrupted or lost for 30 seconds, the Alert "LOST ECDIS COM" is re-
leased.
• When speed stabilization is changed at the ECDIS and [ECDIS] is selected as the
speed data source, the "SPD SOURCE CHG" indication appears.
Selection Explanation Stabilization Mode
[LOG (BT)]*
1
Log, speed over ground (SOG) Ground stabilization
[LOG (WT)] Log, Speed Thru Water (STW) Sea stabilization
[EPFS] Speed input by GPS navigator Ground stabilization
[MANUAL] Manually input speed Sea stabilization
[REF] Echo-referenced speed input Ground stabilization
[ECDIS]*
2
Speed input by ECDIS Ground stabilization or Sea
Stabilization (Dependent on
ECDIS settings).
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