Bridge Navigational Watch Alarm System
A Bridge Navigational Watch Alarm System, abbreviated 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 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.