BNWAS
BNWAS does not ask whether the officer of the watch is competent — it only asks whether someone has touched a reset button recently, which is why a bridge team can defeat its purpose entirely by leaving a weighted object on the reset key.
What to check on a BNWAS.
6 models from JRC in BNWAS. Below: the full model list.
What this type is
The Bridge Navigational Watch Alarm System monitors whether the officer of the watch is present and active on the bridge, escalating through a defined alarm sequence if no activity is detected within a set interval. It is not a fatigue or competence monitor; it detects only physical inactivity at the console — no button press, no motion sensor trigger, no bridge equipment interaction within the timer window. SOLAS makes it mandatory precisely because incapacitation or falling asleep on watch has caused groundings that no other bridge system was designed to catch.
Main components
- Reset points — dedicated buttons or motion sensors positioned around the bridge so the OOW can reset the timer from the normal watchkeeping positions.
- Timer/logic unit — runs the adjustable 3-12 minute inactivity interval and the alarm escalation sequence.
- Stage 1 alarm — visual/audible alert on the bridge itself, giving the OOW a short window to reset.
- Stage 2 alarm — extends the alert, often to a location the OOW would need to move to reset, so a genuinely present but preoccupied officer still resets it.
- Stage 3 backup alarm — sounds in the master's cabin and/or designated officer's cabin(s), and on some installations additional crew spaces, when stages 1 and 2 are not acknowledged.
Selection and sizing
The main selection variable is reset point layout, not the electronics — the points must cover every position the OOW legitimately works from (chart table, radar, bridge wings on vessels where wing watchkeeping is normal) so a genuinely attentive officer is never falsely alarmed for being at a different console. The backup alarm routing (which cabins, which public spaces) must match the vessel's actual watch and manning structure.
Regulations and class
SOLAS Chapter V, Regulation 19, requires BNWAS on all vessels of 150 gross tonnage and upward on international voyages, phased in by vessel type and build date. Performance standards are set out in IMO resolution MSC.128(75), covering the timer ranges, alarm stages and escalation timing. Class survey checks the fitted system carries type approval to this standard and that the alarm sequence and cabin routing match what was tested at commissioning.
Read the full guide
Typical faults
- Reset button wedged or taped down — defeats the entire system while showing no fault, the single most common documented failure mode.
- Motion-sensor reset points triggered by routine bridge movement unrelated to actual watchkeeping, masking genuine inactivity.
- Stage 3 cabin alarm wiring not tested after a crew cabin reassignment, so the backup alert goes to an empty room.
- Timer interval left at a setting inappropriate for the vessel's operation, causing either alarm fatigue or too long a gap before escalation.
What to look for in a supplier
- Type approval to MSC.128(75) with the certificate matching the exact model installed.
- Reset point layout proposal based on the vessel's actual bridge arrangement, not a generic template.
- Backup alarm routing configurable to the vessel's manning and cabin layout.
- Commissioning test report confirming every stage and every cabin alarm was verified, not just stage 1.
Test BNWAS by letting it run through to stage 3 during commissioning and after any crew accommodation change — a system that has only ever been reset at stage 1 has never proven its backup alarm actually reaches anyone.
Models in this type.
The best-documented model of each manufacturer first, then the next — 6 of 6 models in BNWAS. Every row links to full specifications, documents and service notes.
Manufacturers.
All 26 manufacturers with models of BNWAS. Names with a manufacturer page open it; the others open a search across the full library.
All manufacturersAlso in Navigation & Bridge Equipment.
The other equipment types in this category.
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Three things people ask first.
Is BNWAS data free?
Yes. Every model page, every guide and every datasheet for this type is readable without an account. An account adds saved searches and requests, nothing is taken away.
My model is missing — what now?
Send us the nameplate. We identify it by hand, add it to the library, and if you need a part or a service, the request is already on our desk.
Can you source a BNWAS part?
Yes. Tell us the manufacturer, the model and what you need — a person reads every request and replies by e-mail.