During foggy conditions what does one prolonged blast every two minutes mean?

Answer 1

Foggy conditions....a case of restricted visibility... according to International Regulations for Preventing Collision at Sea Rule 35... "A Power driven vessel making way through the water shall sound at intervals of not more than 2 minutes one prolonged blast."

So hearing a prolonged blast every 2 mins in restricted visibility we can deduce that its a power driven vessel making way through water.

Answer 2

One prolonged blast of the ships whistle, in restricted visibility, not exceeding intervals of 2 minutes means that the vessel is making way through the water.

Answer 3

One prolonged blast every two minutes means a vessel is underway.