Top 12 Points a Ship Officer on Watch Should Consider in Restricted Visibility

Discover the 12 critical considerations for ship officers navigating in restricted visibility. Learn how modern practices, international regulations, and best seamanship traditions come together to keep vessels, crews, and marine environments safe.

Introduction

If you have ever stood a watch on a bridge wrapped in a thick, silent fog, you know the subtle sense of unease that comes with it. Suddenly, all your senses are heightened: every echo, every sound signal, every blip on the radar seems magnified.

Restricted visibility is one of the greatest challenges for a ship’s officer on watch. It tests seamanship, nerves, and teamwork to the fullest. While modern technology has made the seas safer than ever, the COLREGs (International Regulations for Preventing Collisions at Sea), bridge resource management principles, and sheer common sense remain indispensable.

This article explores 12 crucial points an Officer of the Watch (OOW) must consider during restricted visibility, drawing on SOLAS requirements, case studies, and real-world lessons that can save lives. Whether you are a cadet just learning or a seasoned master refreshing best practices, these insights will help you stay ready for the moment the horizon disappears.

Why Restricted Visibility Demands Maximum Vigilance

Restricted visibility — caused by fog, heavy rain, snow, or even smoke — can turn a normal watch into a high-risk scenario. According to Lloyd’s List Intelligence (2023), around 23% of serious ship collisions involve some form of restricted visibility.

Modern ships travel faster than ever, with tighter turnaround schedules. In these conditions, the Officer of the Watch must interpret not only the rules of the road but also evolving sensor data, radar overlays, and information from other bridge team members.

In a world where a mistake could mean a costly collision, oil spill, or tragic loss of life, understanding best practice is critical. And while technology assists, it cannot replace a mariner’s awareness and judgement.

1. Keep a Proper Lookout — Always

Perhaps the most fundamental principle of seamanship is enshrined in Rule 5 of the COLREGs: keep a proper lookout by sight and hearing, as well as by all available means.

In restricted visibility, this means:

  • Increasing bridge staffing

  • Minimising distractions

  • Listening carefully for sound signals

  • Checking visually outside even if you rely on instruments

Too many incidents still happen because officers become over-reliant on radar, neglecting to step out onto the bridge wing or to open a wheelhouse window. As the International Maritime Organization reminds officers in the STCW Code, “all means” means precisely that: eyes, ears, radar, AIS, radio — everything.

2. Ensure Safe Speed

Rule 6 of the COLREGs explicitly demands safe speed. In restricted visibility, this is more critical than ever.

Safe speed is not a fixed number. It depends on:

  • Traffic density

  • Manoeuvring capability

  • Stopping distance

  • Radar performance

  • Visibility range

It is wise to err on the side of caution. A ship cannot stop on a dime. Studies in Marine Accident Analysis Review (2022) showed a high proportion of restricted-visibility collisions involved ships proceeding too fast for the conditions.

Slow down. It buys you decision time, which is a priceless commodity at sea.

3. Use Sound Signals Correctly

Sound signals can seem old-fashioned in an era of ECDIS, but they remain essential.

In restricted visibility, the COLREGs Rule 35 requires vessels to make specific signals at intervals. For example, a power-driven vessel making way must sound one prolonged blast at least every two minutes.

Officers should:

  • Double-check the ship’s whistle system

  • Brief the lookout or helmsman about signals

  • Log the signals clearly

When all else fails, sound can still reach beyond the fog. As the Marine Accident Investigation Branch (MAIB) has noted, failure to sound signals is a surprisingly common oversight, even on modern bridges.

4. Master Radar and ARPA Operation

Radar is your lifeline in restricted visibility. But having it is not the same as knowing how to use it.

Ship officers must confidently:

  • Adjust gain and clutter settings

  • Understand sea return

  • Use plotting functions

  • Interpret CPA (Closest Point of Approach) and TCPA (Time to Closest Point of Approach)

Over-reliance on automatic radar plotting (ARPA) is risky if an officer cannot cross-check and manually plot targets in case of doubt.

As The Nautical Institute reminds us, radar is an aid — not a substitute for judgement.

5. Post Additional Lookouts

It is a best practice — and often required by the vessel’s Safety Management System (SMS) — to post extra lookouts in restricted visibility.

For instance, the forward lookout may:

  • Listen for fog signals

  • Confirm visual sightings

  • Report anything that radar does not show

Having an extra pair of ears and eyes gives the bridge team more data to work with, increasing situational awareness.

In a study by DNV Maritime (2021), enhanced lookout routines significantly reduced near-misses during bridge simulator tests of fog scenarios.

6. Use All Available Navigation Equipment

Modern ships carry a wealth of navigation equipment:

  • ECDIS

  • AIS

  • Echo sounders

  • Bridge alarms

  • Gyro repeaters

An OOW should integrate these, rather than focusing on one screen. Cross-checking radar ranges with ECDIS charts, comparing echo sounder depths to charted soundings, or verifying a contact’s AIS name against a radar target are all vital.

Multiple layers of information protect against misinterpretation and blind spots, giving you a clearer picture of what is really around you.

7. Inform the Master

This cannot be stressed enough. SOLAS Chapter V, Regulation 34, makes it plain: the Master must be called if restricted visibility develops, especially near traffic separation schemes, coastal approaches, or narrow fairways.

There is no shame in asking for backup. A rested and experienced Master can:

  • Help interpret the situation

  • Coordinate with traffic services

  • Approve course alterations

Ship incidents often cite failure to call the Master as a factor. It is better to call early and be safe than to call late and be sorry.

8. Follow Company SMS and Bridge Procedures

Modern shipping companies invest heavily in Safety Management Systems, following the ISM Code. These systems often have:

  • Checklists

  • Bridge protocols

  • Crew briefing guidance

In restricted visibility, the bridge team should review these carefully. For example, a tanker’s SMS might dictate minimum engine standby status, speed limits, and when to change from automatic to manual steering.

Following these rules ensures not only compliance with the company’s procedures but also with port-state control and charterer requirements, which could be audited.

9. Be Ready for Manoeuvres

In restricted visibility, the OOW must be prepared for evasive action.

That means:

  • Engines on standby

  • Steering gear tested

  • Clear communications with the engine room

A collision can develop rapidly. If the officer waits to react until a target is within 1 nautical mile, it may be too late. Bridge Resource Management (BRM) techniques strongly encourage “thinking ahead” so the ship is ready to alter course or stop on command.

10. Communicate with Other Vessels

The VHF radio (on Channel 16 or designated working channels) is a valuable tool in restricted visibility.

A simple call:

“Vessel on my port bow, this is Motor Tanker Atlantic Star — what are your intentions?”

— can clarify a risk of collision long before a close-quarters situation arises.

But remember, COLREGs Rule 7 warns not to rely on scanty information. VHF should support collision avoidance, but never replace standard manoeuvres and sound signals.

11. Maintain a Safe Distance from Navigation Hazards

In restricted visibility, you cannot see that reef, shoal, or breakwater until you are dangerously close.

Use:

  • ECDIS safety contours

  • Radar parallel index lines

  • Echo sounder depth alarms

… to maintain a wide berth from hazards.

According to UK Hydrographic Office guidance, giving yourself a wider margin of safety is essential, since positional errors can slip through unnoticed in reduced visibility.

12. Record Everything Meticulously

In the aftermath of a collision, the bridge logbook, radar recordings, and noon reports will come under intense legal scrutiny.

An OOW should record:

  • Visibility estimates

  • Watch changes

  • Position fixes

  • Manoeuvres

  • Sound signals made

This is both a legal protection and a professional habit. As the Maritime and Coastguard Agency (UK MCA) notes, a well-kept log can mean the difference between defending a decision and facing prosecution.

Key Technologies and Developments Driving Change

Today’s bridge teams benefit from stunning advances:

  • ECDIS with dynamic chart updates

  • Integrated Bridge Systems (IBS)

  • Remote Engine Monitoring

  • Dynamic Positioning Systems (DP)

  • Infrared Cameras for fog penetration

Class societies like Lloyd’s Register and ClassNK are constantly reviewing bridge systems to improve human-machine interfaces, making navigation in restricted visibility even safer.

Challenges and Solutions

Challenge: Information overload from multiple systems
Solution: Structured BRM training and cross-check discipline

Challenge: Weather conditions changing too fast for prediction
Solution: Enhanced weather routing and modern oceanographic data

Challenge: Human error during high stress
Solution: Fatigue management and bridge team drills

These challenges will not vanish, but they can be managed through smart design, training, and teamwork.

Future Outlook

Restricted visibility will remain a fact of maritime life — climate change may even increase its frequency through unusual fog patterns or heavy rainfall.

Future officers will likely rely more on:

  • AI-assisted collision avoidance

  • Ultra-high resolution radar

  • Drone-assisted lookout systems

But at the heart of it, good seamanship will remain the same: cautious, alert, respectful of nature, and supported by human collaboration.

FAQ

What is the biggest risk in restricted visibility?
Collision, usually due to loss of situational awareness.

How do you define restricted visibility?
Any condition where you cannot see enough to navigate safely — fog, rain, snow, smoke, or sandstorms.

What equipment is vital?
Radar, ECDIS, AIS, sound signaling devices, echo sounder, and a well-trained lookout.

Do ships still sound fog signals today?
Absolutely — COLREGs Rule 35 still requires them, regardless of modern tech.

What if I cannot see another vessel on radar?
Assume it is there. Use sound signals, post extra lookouts, and proceed with caution.

Should I call the Master?
Yes, especially near coasts, in traffic lanes, or in doubt — better early than late.

Conclusion

In the vast ocean, fog and reduced visibility are constant companions to the seafarer’s journey. These 12 points are more than a checklist: they are a mindset of caution, teamwork, and respect for the sea.

Even in an age of digital navigation, the officer of the watch remains the heart of a safe passage. Let the lessons of mariners past — sharpened by the best modern tools — guide you through any haze that stands in your way.

References

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