Restricted Visibility

Chapter VI – Operations

Section 2c – Restricted Visibility

Restricted Visibility

When operating at night, or other times of restricted visibility, the required navigation lights as set forth in the required equipment section are mandatory to be displayed. The lights themselves will let each vessel know which is the stand-on or give-way vessel and each vessel should react accordingly.

A vessel approaching in your danger zone (approaching from your starboard side) will show its red (stop) port light. That vessel will see your green (go) starboard light. If you do not see a mast light, you know the vessel is not power driven (or not operating under its own power, as in the case of a boat being towed) and has the right of way over power driven vessels.

During nighttime operations vision can be tricky at best, so a proper lookout and safe speed need constant attention.

During times of restricted visibility such as smoke or fog, additional sound signals are required. Both inland and international rules require that any vessel underway in or near a restricted visibility area sound a warning signal every two minutes.

Motorboats must sound one prolonged blast every two minutes. Sailing vessels must sound one prolonged blast plus two short blasts every two minutes. When a power driven vessel is stopped (underway but making no way) she shall sound two prolonged blasts every two minutes. Vessels at anchor shall sound rapid strokes on the bell for 5 seconds at intervals not less than one minute (however, if your vessel is less than 65 feet and you are anchored in a designated “special anchorage” you do not need to sound these signals). Vessels aground shall sound three distinct strokes on the bell (“I Am Aground”), followed by five seconds rapid ringing of the bell, followed by three distinct strokes on the bell (“I Am Aground”).

One Prolonged Blast One Short Blast
One Stroke on the Bell

 

Power Vessel Underway Every Two Minutes
Sailing Vessel Underway Every Two Minutes
Power Vessel Underway but making no way
Vessel at Anchor Every Minute	5 seconds of rapid ringing
Vessel Aground Every Minute	3 strokes 5 seconds rapid ringing 3 strokes