5 Operational requirements
5.1 Functionality
5.1.1 Steering modes
A track control system should be able to steer the ship from her position:
.1 to a single waypoint; or
.2 along a sequence of waypoints.
5.1.2 Starting requirements
The system should allow the officer of the watch to start track control only if
- the ship's position,
- the difference between track course and actual heading,
- the ship's manoeuvrability,
will result in a safe approach manoeuvre to the track.
5.1.3 Primary position-fixing system
The primary position-fixing system used for track control should be an electronic position-fixing system (EPFS) approved by the Organization.
5.1.4 Position monitoring
The ship's position should be continuously monitored by a second independent position source. This monitoring need not be an integral part of the track control system.
5.1.5 Early course change indication
In the case of track control by a sequence of waypoints, an early course change indication should be given no later than 1 min before the wheel-over line.
5.1.6 Actual course change and confirmation
(1) In the case of track control by a sequence of waypoints, an alarm should be given at the wheel-over line.
(2) The system should provide means for the officer of the watch to confirm the course change at wheel-over.
(3) With or without the confirmation, the ship should follow automatically the track.
(4) If the actual course change alarm is not confirmed by the officer of the watch within 30 s of wheel-over, a back-up navigator alarm should be given.
