Take 10 #36: Restricted visibility

31 May 2024 The Navigator

Ten tips for handling restricted visibility at sea, maintaining a good lookout and operating within the relevant Colregs

1 Professional approach

Restricted visibility is a challenge to navigation, requiring a professional approach. Make sure you know how to assess whether visibility is restricted.


2 Fog factor

Restricted visibility can be caused by a number of factors, including fog, mist, snow and sandstorms. Some of these circumstances come slowly, others more quickly. Either way, the professional navigator must be ready to react.


3 Planning ahead

Many sources of restricted visibility can be anticipated and should be part of the risk assessment during passage planning.


4 In or nearby

Areas of restricted visibility can affect you both when you are in one and when you are nearby. It can obscure collision risks, such as multiple vessels in an approaching squall.


5 All available means

A good lookout should always be maintained. In restricted visibility, ‘all available means’ includes all appropriate technology along with extra lookouts.


6 Safe speed

The key to safety in restricted visibility is to ensure that your speed is appropriate to the circumstances so that you can avoid collision or stop the vessel more easily.


7 Colregs

Responsibilities of vessels under Colregs change in restricted visibility. When ‘in sight’, there are rules for ‘stand on’ and ‘give way’ vessels. During restricted visibility, all vessels should take action to avoid collision.


8 Procedures matter

Every vessel should have procedures to ensure that safety is maintained in restricted visibility. These will include SMS procedures, Master’s orders and practising good seamanship.


9 Drills

Restricted visibility drills can be useful to help bridge teams prepare to adapt to this situation.


10 Mentoring

Learning how to deal with restricted visibility comes with experience; mentor others in your team to be able to recognise the situation and react positively to it.


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