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Home › Navigation › BNWAS and Anti-Collision Alert Systems
Operational guide · Safety & equipment

BNWAS and Anti-Collision Alert Systems

SOLAS requires BNWAS operational whenever under way at sea; MSC.128(75) separately defines automatic, manual ON and manual OFF modes and reserves mode and dormant-period controls to the Master.

BNWASSOLAS V/19anti-collision alertwatchkeeping

Operational Explanation

Do not confuse the SOLAS operational requirement with automatic-mode logic linked to the heading/track control system. MSC.128(75) provides automatic, manual ON and manual OFF; mode and dormant-period controls are protected and accessible to the Master. Testing and maintenance follow maker, PMS/SMS, flag/class and survey instructions.

Regulatory Reference

SOLAS V/19: BNWAS operational whenever the ship is under way at sea. MSC.128(75): modes, dormant period, alarm sequence, reset, security and malfunctions.

Scope of Application

Ships subject to the carriage requirement under relevant dates and thresholds. A full-sequence test is ship procedure/good practice where prescribed, not a universal IMO periodicity.

Procedure / How to Complete It

  1. Verify that the selected mode makes BNWAS operational under way at sea.
  2. The Master sets/protects mode and dormant period under the SMS and conditions.
  3. Test sequence, reset points and remote alarms under maker, PMS/SMS and statutory instructions.
  4. Do not simulate main-power failure unless procedure and maker authorise it.
  5. Record tests, defects, isolation and corrective action under the ship's system.

Practical Example

Autopilot disengaged does not mean BNWAS is not required: when under way at sea the system must be operational in the appropriate mode.

What Typically Goes Wrong

Presenting under way and autopilot as alternative triggers or inventing a uniform IMO periodicity for end-to-end/power-failure tests.

Common Mistakes Mistake Library

MistakeConsequenceHow to Avoid It
Presenting under way and autopilot as alternative triggers or inventing a uniform IMO periodicity for end-to-end/power-failure tests.Incorrect operational decision or regulatory statusUse the primary reference and ship-specific procedure

What the PSCO Checks

Operational status under way, access security, dormant setting, alarm sequence, reset locations, records and defect management.

Operational Tips

Preparation checklist

FAQ

Does automatic mode mean BNWAS is needed only with autopilot?
No. SOLAS requires it operational whenever under way at sea; automatic is an equipment mode.
Is there one IMO periodic test for every ship?
No. Method and frequency follow maker, PMS/SMS and applicable statutory instructions.
Who controls mode and dormant period?
The Master through protected access.

Related Topics

WatchkeepingBridge Resource Management

Last substantive revision of this page: 31 August 2026 · page fingerprint c9ace3905f9d