Furuno FA-2805, Operator'S Manual

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2-4
5. Enter the ship speed by hitting corre-
sponding numeric keys followed by the
ENTER key without omitting leading
zeroes, if any. As an example, if the ship
speed is 8 knots, press [0] [8] [ENTER].
For 4.5 knots, [0] [4] [5] [ENTER].
6. Press the RADAR MENU key to close
the FUNCTIONS menu. The ship
speed readout at the screen top shows
own ship's speed you entered pre-
ceded by the label "MANU."
Target-based speed
The use of target-based speed is recom-
mended when:
• The speed log is not operating prop-
erly or not connected to the radar.
• The vessel has no device which can
measure ship's leeward movement
(doppler sonar, speed log, etc.) though
leeward movement can not be disre-
garded.
If you select target-based speed, the Auto
Plotter calculates own ship's speed rela-
tive to a fixed reference target.
Note: When the target-based speed is
adopted, automatically or manually en-
tered ship's speed is disregarded.
To establish target-based speed:
1. Select a small fixed island or any radar
prominent point located at 0.2 to 24 nm
from own ship.
2. Place the cursor (+) on the target by
operating the trackball.
3. Press the TARGET BASED SPEED
key.
The reference target mark (see below)
appears at the cursor position and the
own ship data label changes from
"LOG," "NAV" or "MANU" to "REF."
Note that it takes one minute before a
new speed is displayed.
R
Reference target mark
Notes:
1) When the reference target is lost or
goes out of the acquisition range, the
reference target mark blinks and the
speed reads "xx.x." Select a different
reference target in this case.
2) When all targets are deleted, the refer-
ence target mark is also deleted and
the target-based speed becomes in-
valid. The speed is indicated in KTBT
where BT means Bottom Track (speed
over ground).
3) The vector of the reference target can
be displayed by menu operation (Auto
Plot 1 menu).
Canceling target-based speed
To cancel the target-based speed, just
press the TARGET BASED SPEED key.
The speed is shown by LOG, NAV* or
MANUAL as selected previously. (NAV
only on R-type)
Deactivating the ARPA
To deactivate the ARPA, just press the
AUTO PLOT key. Target plotting symbols
and the on-screen label ARPA will disap-
pear.
Note: Even when the ARPA is turned off,
target tracking still goes on until the radar
is turned off. (For G-type, target tracking
goes off at STBY.)
2.5 Automatic Acquisition
The ARPA can acquire up to 40 targets
(20 automatically and 20 manually or all
40 manually. If AUTO ACQ is selected af-
ter more than 20 targets have been manu-
ally acquired, only the remaining capacity
of targets can be automatically acquired.
For example, when 30 targets have been
acquired manually, then the ARPA is
switched to AUTO ACQ. Only 10 targets
can be acquired automatically. A target just
acquired automatically is marked with a
broken square and a vector appears about