Periodic operation of a ship at sea (coastal, restricted or unrestricted service) under the supervision of a single watch-keeper on the bridge is becoming normal practice. Similar to an engine-room with one man on watch, the basic requirements are as follows:
Alarm and warning systems associated with navigation equipment are centralised for efficient identification, both visible and audible.
The following alarms have to be provided on ship’s bridge :
– Closest Point of Approach (CPA) from the radars
– Shallow depth from the echo – sounder
– Waypoint approach if auto – track is installed
– Off – course alarm from a device independent from autopilot or gyro-compass -
-Off – track alarm if auto track is provided
– Steering alarms
– Navigation-lights alarms
– Gyro-compass alarms
– Watch safety – system failure alarm
– Power – supply failure alarms of nautical distribution panels and, if dual, both for normal as well as back-up supply circuits.
All alarms have to be fail-safe, so that failure of the device or power supply to the device triggers an alarm.
Failure of the power supply to the bridge-alarm system shall be monitored by the engine-room alarm and engine-room monitoring system.
A watch safety system to monitor the well-being and awareness of the watch-keeper is provided.
The watch-keeper confirms his well being by accepting a warning at a maximum 12 minutes interval.
When the watch-keeper fails to respond to accept the warning with in 30 seconds or fails to accept a bridge alarm within 1 minute, a fixed installed system initiates a watch alarm to the captain’s cabin and to the back-up navigator’s cabin.
The flag-states, however, do not accept a single watch-keeper on the bridge for passenger-ships, so this bridge always has to be manned by at least two officers when underway with passengers.
Integrated bridge system on ship
Other possibilities for the notation of navigation functions are
Integrated Bridge Navigation Systems.
This configuration requires, in addition to the one-man-on- bridge requirements:
– duplicated gyro-compasses,
– GPS system,
– route-planning capabilities,
– auto track capability electronic chart display (ECDIS).