The old saying, “Be able to stop in half the distance of your visibility,” is a very good nautical yardstick to use when boating, because travelling through thick fog and mist needs to be done with the utmost care and caution. Slower is always better when visibility is compromised.
FOG SIGNALS SOUNDED
Power-driven vessels, that are making way, need to give one prolonged blast every two minutes to alert nearby vessels of their presence. Power-driven vessels
that are stationary need to give off two prolonged blasts every two minutes with a one second interval between them. Sailing boats, vessels restricted in their ability to manoeuvre, vessels constrained by draft, vessels engaged in fishing, towing or pushing another vessel need to give off one prolonged blast followed by two short blasts every two minutes.