BNWAS
medium
7 models total
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.
Read more — BNWAS explained ▾
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.
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.
7 manufacturers · 7 models
Alphatron Marine
1
AlphaBridge BNWAS
3-stage alarm
· Navigation Data / Sensor
· Bridge Navigational Watch Alarm System
Stages
3
IMO Approved
ja
Common Failures & Inspection Points
- Sensor, camera or input failure causes missing data, blank images or channel alarms
- Power-supply, UPS or network faults cause system restart, loss of recording or unavailable remote status
- Storage-media or recorder faults cause gaps in retained data or failed self-tests
- Incorrect time, configuration or interface data causes inconsistent records or false alarms
- Control, acknowledgment or communication faults cause unavailable watchkeeping or security functions
Service: Review self-tests, event logs, time synchronization, power supplies, storage status and connected sensor channels. Verify required alarms and communication paths under the approved procedure without sending unauthorized security alerts. Check data quality and retention status where applicable. Refer to manufacturer and statutory documentation for the exact figure for test and retention criteria.
Spare Parts: Carry approved storage or recorder modules where supported, power supplies, network interfaces, camera parts, fuses and backed-up configuration data.
Strengths
- Three‑stage alarm hierarchy meets IMO Resolution requirements out of the box
- Can operate both fully integrated with AlphaBridge systems and independently, offering flexibility for retrofits
- IMO approved (Resolution A.938(23)) ensuring regulatory compliance on international voyages
- Compact software architecture simplifies installation on existing bridge consoles
Weaknesses
- Relies heavily on the vessel’s data bus; a failure in the bus can disable alarm functions
- Sensor detection range is limited, requiring careful placement to guarantee coverage of all bridge workstations
- Alarm escalation timing has been reported as slower than some competitor systems, potentially delaying crew response
Typical Vessels:
TankerContainer shipBulk carrierPassenger vesselOffshore supply vessel
Certifications:
IMO Approved
Decision Guide: Choose if you need a BNWAS that can be tightly integrated with an existing Alphatron bridge suite while still retaining standalone capability for vessels with limited IT infrastructure. Avoid if your ship’s data‑bus reliability is questionable or if rapid alarm escalation is a critical safety requirement.
Use Cases: Voyage recording, bridge watchkeeping, onboard surveillance and statutory security functions.
AMI Marine
1
BNWAS
3-stage alarm
· Navigation Data / Sensor
· Bridge Navigational Watch Alarm System
Stages
3
IMO Approved
ja
Common Failures & Inspection Points
- Sensor, camera or input failure causes missing data, blank images or channel alarms
- Power-supply, UPS or network faults cause system restart, loss of recording or unavailable remote status
- Storage-media or recorder faults cause gaps in retained data or failed self-tests
- Incorrect time, configuration or interface data causes inconsistent records or false alarms
- Control, acknowledgment or communication faults cause unavailable watchkeeping or security functions
Service: Review self-tests, event logs, time synchronization, power supplies, storage status and connected sensor channels. Verify required alarms and communication paths under the approved procedure without sending unauthorized security alerts. Check data quality and retention status where applicable. Refer to manufacturer and statutory documentation for the exact figure for test and retention criteria.
Spare Parts: Carry approved storage or recorder modules where supported, power supplies, network interfaces, camera parts, fuses and backed-up configuration data.
Strengths
- Meets mandatory IMO SOLAS BNWAS requirement at a lower purchase cost
- Three‑stage alarm logic provides graduated alerts for watchkeeper inactivity
- Compact design suitable for retrofitting on existing bridge consoles
Weaknesses
- Sensor reliability reported as inconsistent, potentially leading to false alarms or missed alerts
- Limited global service and support network may increase downtime for vessels operating far from major ports
- Configuration interface is complex, requiring experienced personnel for proper setup
Typical Vessels:
TankerBulk CarrierContainer ShipGeneral Cargo VesselPassenger Ferry
Certifications:
IMO (SOLAS) approved
Decision Guide: Choose if: you need a cost‑effective BNWAS that satisfies SOLAS compliance on vessels with limited budget and can accept a modest learning curve for configuration. Avoid if: sensor reliability is critical, you operate in remote regions without easy access to AMI Marine service centres, or you prefer a turnkey system with extensive after‑sales support.
Use Cases: Voyage recording, bridge watchkeeping, onboard surveillance and statutory security functions.
Consilium Marine
1
Salwico BNWAS
3-stage alarm
· Navigation Data / Sensor
· Bridge Navigational Watch Alarm System (BNWAS)
Stages
3
IMO Approved
ja
Common Failures & Inspection Points
- Sensor, camera or input failure causes missing data, blank images or channel alarms
- Power-supply, UPS or network faults cause system restart, loss of recording or unavailable remote status
- Storage-media or recorder faults cause gaps in retained data or failed self-tests
- Incorrect time, configuration or interface data causes inconsistent records or false alarms
- Control, acknowledgment or communication faults cause unavailable watchkeeping or security functions
Service: Review self-tests, event logs, time synchronization, power supplies, storage status and connected sensor channels. Verify required alarms and communication paths under the approved procedure without sending unauthorized security alerts. Check data quality and retention status where applicable. Refer to manufacturer and statutory documentation for the exact figure for test and retention criteria.
Spare Parts: Carry approved storage or recorder modules where supported, power supplies, network interfaces, camera parts, fuses and backed-up configuration data.
Strengths
- IMO‑approved 3‑stage alarm escalation ensures regulatory compliance
- Compact design suitable for limited bridge space
- Adjustable motion sensor sensitivity for different vessel motions
- Simple mechanical reset button for quick manual acknowledgement
- Proven field record on a variety of passenger and offshore vessels
Weaknesses
- Motion sensor can drift over time, requiring periodic recalibration
- Reset button membrane may wear out after many activations
- Alarm relay has reported failures in high‑vibration installations
- Limited built‑in diagnostics compared with newer networked BNWAS units
- Correct sensor placement is critical; poor mounting reduces reliability
Typical Vessels:
Passenger ferryCruise shipOffshore supply vesselRo‑Ro passenger vesselContainer ship (where watch monitoring is required)
Certifications:
IMO
Decision Guide: Choose if: you need an IMO‑compliant, three‑stage BNWAS with a straightforward mechanical reset and proven installation on passenger vessels. Avoid if: you require advanced remote diagnostics, network integration, or have high‑vibration environments where relay reliability is critical.
Use Cases: Voyage recording, bridge watchkeeping, onboard surveillance and statutory security functions.
JRC
1
JBN-95
3-stage alarm
· Navigation Data / Sensor
· bridge watch alarm system
Stages
3
IMO Approved
ja
Common Failures & Inspection Points
- Sensor, camera or input failure causes missing data, blank images or channel alarms
- Power-supply, UPS or network faults cause system restart, loss of recording or unavailable remote status
- Storage-media or recorder faults cause gaps in retained data or failed self-tests
- Incorrect time, configuration or interface data causes inconsistent records or false alarms
- Control, acknowledgment or communication faults cause unavailable watchkeeping or security functions
Service: Review self-tests, event logs, time synchronization, power supplies, storage status and connected sensor channels. Verify required alarms and communication paths under the approved procedure without sending unauthorized security alerts. Check data quality and retention status where applicable. Refer to manufacturer and statutory documentation for the exact figure for test and retention criteria.
Spare Parts: Carry approved storage or recorder modules where supported, power supplies, network interfaces, camera parts, fuses and backed-up configuration data.
Strengths
- Three‑stage monitoring meets IMO SOLAS BNWAS requirements out of the box
- Full integration with existing JRC bridge alarm panels simplifies wiring and configuration
- IMO approved (SOLAS) ensures regulatory compliance for passenger and cargo vessels
- Modular design allows retrofitting on new builds or existing ships without major modifications
Weaknesses
- Reported sensor zone coverage gaps can leave blind spots in larger bridge layouts
- Alarm timer adjustment may be cumbersome, requiring specialist service to fine‑tune intervals
- Indicator LED failures have been noted, potentially masking alarm status until repaired
- Proprietary interface limits compatibility with non‑JRC bridge systems
Typical Vessels:
Passenger ferryCruise shipOffshore supply vesselContainer shipTanker
Certifications:
IMO approved
Decision Guide: Choose if: you already use JRC bridge alarm equipment, need a ready‑made IMO‑compliant three‑stage BNWAS, and value integrated monitoring on passenger or high‑risk vessels. Avoid if: you require extensive sensor coverage across a large bridge area, prefer an open‑interface system, or have experienced reliability issues with timer settings in the past.
Use Cases: Voyage recording, bridge watchkeeping, onboard surveillance and statutory security functions.
Kelvin Hughes
1
BNWAS
3-stage alarm
· Navigation Data / Sensor
· Bridge Navigational Watch Alarm System
Stages
3
IMO Approved
ja
Common Failures & Inspection Points
- Sensor, camera or input failure causes missing data, blank images or channel alarms
- Power-supply, UPS or network faults cause system restart, loss of recording or unavailable remote status
- Storage-media or recorder faults cause gaps in retained data or failed self-tests
- Incorrect time, configuration or interface data causes inconsistent records or false alarms
- Control, acknowledgment or communication faults cause unavailable watchkeeping or security functions
Service: Review self-tests, event logs, time synchronization, power supplies, storage status and connected sensor channels. Verify required alarms and communication paths under the approved procedure without sending unauthorized security alerts. Check data quality and retention status where applicable. Refer to manufacturer and statutory documentation for the exact figure for test and retention criteria.
Spare Parts: Carry approved storage or recorder modules where supported, power supplies, network interfaces, camera parts, fuses and backed-up configuration data.
Strengths
- IMO‑approved, meeting SOLAS Chapter V watch alarm requirements
- Three‑stage escalation (warning, alarm, emergency) provides clear progression of alerts
- Seamless integration with Kelvin Hughes bridge consoles and radar suites
- Highly configurable thresholds and response times to suit different vessel operations
- Proven track record on passenger ships and offshore support vessels
Weaknesses
- Integration can be problematic with non‑Kelvin Hughes bridge alarm panels
- Configuration interface is complex, requiring specialist training
- Sensor reliability issues reported in harsh marine environments
- Limited third‑party compatibility compared with some open‑architecture BNWAS solutions
- Upgrades may require firmware coordination across the entire Kelvin Hughes suite
Typical Vessels:
Passenger ferryCruise shipOffshore supply vesselPlatform support vesselHigh‑speed craft
Certifications:
IMO ApprovedSOLAS compliant
Decision Guide: Choose if you operate vessels that must meet SOLAS watch‑alarm requirements and already use Kelvin Hughes bridge equipment, or need a highly configurable three‑stage alarm system. Avoid if your bridge suite is from another vendor, you lack in‑house expertise for complex configuration, or sensor robustness is a primary concern.
Use Cases: Voyage recording, bridge watchkeeping, onboard surveillance and statutory security functions.
Netwave
1
NW-BNWAS
3-stage alarm
· Navigation Data / Sensor
· Bridge Navigational Watch Alarm System (BNWAS)
Stages
3
IMO Approved
ja
Common Failures & Inspection Points
- Sensor, camera or input failure causes missing data, blank images or channel alarms
- Power-supply, UPS or network faults cause system restart, loss of recording or unavailable remote status
- Storage-media or recorder faults cause gaps in retained data or failed self-tests
- Incorrect time, configuration or interface data causes inconsistent records or false alarms
- Control, acknowledgment or communication faults cause unavailable watchkeeping or security functions
Service: Review self-tests, event logs, time synchronization, power supplies, storage status and connected sensor channels. Verify required alarms and communication paths under the approved procedure without sending unauthorized security alerts. Check data quality and retention status where applicable. Refer to manufacturer and statutory documentation for the exact figure for test and retention criteria.
Spare Parts: Carry approved storage or recorder modules where supported, power supplies, network interfaces, camera parts, fuses and backed-up configuration data.
Strengths
- IMO‑approved three‑stage compliance ensures regulatory acceptance
- Cost‑effective solution compared with many premium BNWAS units
- Can be integrated with Netwave VDR packages for a unified bridge safety system
- Simple user interface and straightforward installation on most vessel bridges
- Provides audible, visual and tactile alarms to cover multiple failure scenarios
Weaknesses
- Alarm sensor must be precisely positioned; mis‑placement can cause false alarms or missed alerts
- Reported power‑supply sensitivity may require additional backup circuitry
- Alarm circuit board failures have been noted in field service reports
- Limited advanced diagnostics and remote monitoring features compared with higher‑end competitors
- No built‑in redundancy for the sensor module; relies on a single point of detection
Typical Vessels:
TankersBulk carriersContainer shipsPassenger vesselsOffshore supply vessels
Certifications:
IMO SOLAS
Decision Guide: Choose if you need an IMO‑compliant BNWAS at a competitive price and plan to pair it with Netwave VDR equipment. Avoid if your vessel requires high redundancy, advanced remote diagnostics, or you cannot guarantee precise sensor placement during installation.
Use Cases: Voyage recording, bridge watchkeeping, onboard surveillance and statutory security functions.
SAM Electronics
1
BNWAS
3-stage alarm
· Navigation Data / Sensor
· Bridge Navigational Watch Alarm System (BNWAS)
Stages
3
IMO Approved
ja
Common Failures & Inspection Points
- Sensor, camera or input failure causes missing data, blank images or channel alarms
- Power-supply, UPS or network faults cause system restart, loss of recording or unavailable remote status
- Storage-media or recorder faults cause gaps in retained data or failed self-tests
- Incorrect time, configuration or interface data causes inconsistent records or false alarms
- Control, acknowledgment or communication faults cause unavailable watchkeeping or security functions
Service: Review self-tests, event logs, time synchronization, power supplies, storage status and connected sensor channels. Verify required alarms and communication paths under the approved procedure without sending unauthorized security alerts. Check data quality and retention status where applicable. Refer to manufacturer and statutory documentation for the exact figure for test and retention criteria.
Spare Parts: Carry approved storage or recorder modules where supported, power supplies, network interfaces, camera parts, fuses and backed-up configuration data.
Strengths
- Three‑stage alarm sequence provides graduated escalation for missed responses
- IMO approved and fully compliant with SOLAS Chapter V
- Seamless integration with SAM/Wärtsilä NACOS bridge suite for unified monitoring
- Modular design allows retro‑fit on existing vessels with minimal wiring changes
- Proven field record on a wide range of commercial ships
Weaknesses
- Reported integration challenges when coupling with non‑SAM bridge systems
- Limited functionality in standalone mode; relies heavily on NACOS for full feature set
- Transition to Wärtsilä ownership has created short‑term support and spare‑parts uncertainties
- Higher upfront cost compared with basic, stand‑alone BNWAS units
Typical Vessels:
Passenger shipsTankersContainer vesselsBulk carriersOffshore supply vesselsGeneral cargo ships
Certifications:
IMO SOLAS
Decision Guide: Choose if you are installing or upgrading a SAM/Wärtsilä NACOS bridge system and need an IMO‑approved, three‑stage BNWAS with integrated alarm management. Avoid if your vessel uses a different bridge architecture, requires a low‑cost stand‑alone solution, or cannot accommodate the current support transition period.
Use Cases: Voyage recording, bridge watchkeeping, onboard surveillance and statutory security functions.