Bridge Navigational Watch Alarm System (BNWAS) is an essential safety system used on ships to monitor the activity and alertness of the bridge watchkeeping crew. Its purpose is to prevent accidents by detecting the incapacity of the officer on watch (OOW) and notifying the captain or another qualified OOW.
The BNWAS operates through a series of stages and alarms to ensure continuous monitoring of the bridge watchkeeping crew. Here are the stages:
Stage 1: When the autopilot is engaged, the bridge officer is required to confirm their presence to the BNWAS system every 3 to 12 minutes. This confirmation is done by either moving an arm in front of a motion sensor or pressing a confirmation button in response to a flashing light.
Stage 2: If a confirmation signal fails to occur within 15 seconds in Stage 1, an alarm will sound on the bridge. If there is still no confirmation signal after an additional 15 seconds, the alarm will extend to the captain’s and the first officer’s cabins. At this point, either the captain or the first officer must 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 (usually between 90 seconds and 3 minutes, depending on the vessel’s size), the alarm will sound in locations where other personnel are available. This ensures that immediate assistance can be provided if required.
The BNWAS is designed to enhance safety on the bridge by continuously monitoring the watchkeeping crew’s alertness. It helps prevent accidents caused by incapacitation or lack of attention of the OOW. By providing timely alarms and notifications, the BNWAS ensures that appropriate actions can be taken to maintain the safety of the vessel and its crew.
It is important for ship operators to comply with the regulations and guidelines regarding the installation and operation of BNWAS as specified by relevant maritime authorities.