What is BNWAS (Bridge Navigational Watch Alarm System)?
A Bridge Navigational Watch Alarm System,( BNWAS) , is an automatic system which sounds an alarm if the watch officer on the bridge of a ship falls asleep, becomes otherwise incapacitated, or is absent for too long a time. The BNWAS is automatically engaged when the ship’s autopilot is activated.
The bridge navigational watch alarm system shall be in operation whenever the ship is underway at sea;
Bridge Navigational Watch & Alarm System – BNWAS is a monitoring and Alarm system which notify other navigational officers or master of the ship if the officer on watch (OOW) does not responds or he/she is incapable of performing the watch duties efficiently which can lead to maritime accidents.
The minimum requirement for a BNWAS under International Maritime Organization standards is to have a dormant stage and three alarm stages, except that on a non-passenger vessel, the second stage may be omitted.
Stage 1: When the autopilot is engaged, the bridge officer is required to signal his presence to the BNWAS system every 3 to 12 minutes in response to a flashing light, either by moving an arm in front of a motion sensor, pressing a confirmation button, or directly applying pressure to the BNWAS centre.
Stage 2: When a confirmation signal fails to occur within 15 seconds in Stage 1, an alarm will sound on the bridge, and if there is still no confirmation signal after a further 15 seconds, in the captain’s and the first officer’s cabins. One of them must then go to the bridge and cancel the alarm.
Stage 3: If neither the captain nor the first officer cancels the alarm within a specified time period (between 90 seconds and 3 minutes depending on the size of the vessel), an alarm will sound in locations where other personnel are usually available.