Question of the week

Fog is defined as visibility of less than 1000m

 

The shipping forecast does not use the word fog in its forecasts. When describing visibility it uses; 

Good Visibility of more than 5 nautical miles

Moderate Visibility between 2 and  5 nautical miles

Poor Visibility between 1000m and 2 nautical miles

Very poor Visibility of less than 1000m

 

Fog is formed when warm moist air passes over relatively cold water, the moist air cools and when humidity reaches 100%, fog forms. Much in the same way when you have a cold drink perhaps with ice out in the sun for a more dramatic effect, water droplets gather on the side of the glass.

 

When encountering fog; reduce to a speed to which you can react to any situation in the prevailing visibility and navigate with extreme caution, put a fix on the chart, switch on navigation lights, if you have the crew availability - man the radar and radio and post extra lookouts.  

Consider occasionally stopping and listening for other vessels and sound signals. 

If you are close to shore, consider heading for safe shallow water and anchoring to wait it out.  - using the sound signal for a vessel at anchor.

Whilst not every vessel will carry AIS, if you have the capability, you could look online at marine traffic Marine Traffic and get a good feel for larger vessels around you but be mindful that it is only a guide to what may be there, do not rely on it being the only traffic around. 

Sound signal for a PDV underway 1 long blast not more than 2 mins apart, if stopped, 2 long blasts (with an interval of around 2 second between them)  at an interval of not more than 2 minutes. 

For a sailing vessel it is one long blast followed by 2 short blasts at an interval of not more than 2 minutes. 

For a vessel at anchor you could sound 3 blasts - 1 short, 1 long, 1 short - at intervals of not more than 1 minute.

 

You could argue that your vessel being less than 12m, you do not have to make any sound signals. However, rule 35(j) that states; A vessel of less than 12m in length shall not be obliged to give the above mentioned signals but, if she does not, shall make some other efficient sand signal at intervals of not more than 2 minutes.

COLREGS rules 19 and 35 are the reference.