Furuno FR-7062, FR-7252 manual Mode and Length of Vectors, True or relative vector, Vector length

6.8 Mode and Length of Vectors

True or relative vector

Target vectors are displayed in relative or true mode. Own ship does not have a vector in rela- tive mode.

Vector length

From the ARP-10 MENU, Vector Length can be set to 30 seconds, 1, 3, 6, 15 or 30 minutes and the selected vector time is indicated on the screen.

The vector tip shows an estimated position of the target after the selected vector time elapses. It can be valuable to extend the vector length to evaluate the risk of collision with any target.

Past position display

The ARP-10 displays equally time-spaced dots (maximum 5 dots) marking the past positions of any targets being tracked.

If a target changes its speed, the spacing will be uneven. If it changes course, its plotted course will not be a straight line in TM mode.

Operational warnings

There are two main situations which cause the ARP-10 to trigger visual and audible alarms:

∙CPA/TCPA alarm

∙Lost target alarm

CPA/TCPA alarm

Visual and audible alarms are generated when the predicted CPA and TCPA of any target be- come less than their preset limits. The audible alarm continues for 10 seconds.

The ARP-10 continuously monitors the pre- dicted range at the Closest Point of Approach (CPA) and predicted time to CPA (TCPA) of each tracked target to own ship.

When the predicted CPA of any target becomes smaller than a preset CPA alarm range and its predicted TCPA less than a preset TCPA alarm limit, the ARP-10 releases an audible alarm. In addition, the target plot symbol changes to a triangle and flashes together with its vector.

Provided that this feature is used correctly, it will help prevent the risk of collision by alert- ing you to threatening targets. It is important that GAIN, A/C SEA, A/C RAIN and other ra- dar controls are properly adjusted and the ARP- 10 is set up so that it can track targets effectively.

CPA/TCPA alarm ranges must be set up prop- erly taking into consideration the size, tonnage, speed, turning performance and other charac- teristics of own ship.

Follow the steps shown below to set the CPA/ TCPA alarm ranges:

1.Open the “ARP-10 MENU”.

2.On the “CPA Set” line, select a CPA limit desired. (Off, 0.5, 1, 2, 3, 5, 6 nm)

3.Press the [ACQ/ENTER] key.

4.On the “TCPA Set” line, select a TCPA limit desired. (30s, 1, 2, 3, 4, 5, 6, 12M)

5.Press the [ACQ/ENTER] key.

6.Press the [MENU] key to close the menu.

The flashing of the triangle plot symbol and vector remains on the screen until the danger- ous situation is no longer present or you inten- tionally terminate tracking of the target by using the [SELECT/CANCEL] key.

Lost target alarm

When the system detects a loss of a tracked tar- get, the target symbol becomes a flashing dia- mond.

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