How To Enter Own Ship Speed; Echo-Referenced Speed Input - Furuno FAR-2218-BB Operator's Manual

3.6

How to Enter Own Ship Speed

The TT requires own ship's speed and heading data. The speed can be STW, SOG
or echo-referenced speed (based on 3 max. stationary objects). Manual input is also
possible. For automatic or manual input, see section 1.12. For echo-referenced speed
input follow the procedure below.
3.6.1

Echo-referenced speed input

The use of echo-referenced speed is recommended when:
• The speed log is not operating properly or not connected to the radar.
• The vessel has no device (doppler sonar, speed log, etc.) that can measure ship's
bow-stern, port-starboard movement.
If you select echo-referenced speed, the TT calculates own ship's speed relative to a
fixed reference target. The number of targets may be R1, R2 or R3. When a plural of
objects are selected, the mean value is used, for stabilization and speed.
1. Right-click the operational display area to show the [CURSOR MENU].
2. Select [REF MARK]. The cursor is highlighted to indicate that the reference mark
function is active.
3. Place the cursor on a fixed echo (such as an island, etc.) at a range of 0.1 to 24
NM from own ship, to be used as a reference, then left-click. The cursor changes
from the highlighted cross to a circle with dashed lines, indicating that the refer-
ence location is now set. See section 3.9 for more information on TT symbols and
their attributes.
At acquisition
The dashed lines of the reference point change to a solid line over time, as shown
in the figure above.
4. Repeat step 3 until to place up to three reference points.
5. Right-click to deactivate the reference mark func-
tion.
6. Right-click the [SPD] indication at the top-right of
the screen to show the [SPEED] menu.
7. Select [2 SHIP SPEED].
8. Select [REF].
9. Close the menu.
It takes approximately one minute for the speed
to appear in the own ship information box. When
the speed appears, the indication "REF BT" also
appears to the right of the speed value.
Stable tracking
3. TARGET TRACKING (TT)
3-5