Two short blasts mean that one intends to overtake the other on the port side. One short blast, on the other hand, means that one intends to overtake the other on the starboard side.
Passing on your right side.Signals are (number of blasts):1. Passing you on your left (port) side2. Passing you on your right (starboard) side3. I am moving backwards (astern)4. Danger, don't do that (answer to the other three if dangerous)One short blast means 'I am changing course to starboard.'Two short blasts mean 'I am changing course to port.'Three short blasts mean 'I am operating astern.'Two prolonged blasts followed by one short blast to mean 'I intend to overtake you on your starboard side';Two prolonged blasts followed by two short blasts to mean 'I intend to over-take you on your port side.'A long blast every two minutes is used when operating in fog.
Means it's about to turn to port.
Passing on your starboard (right) side.
I intend to pass you on my starboard (right) side.
Two short blast shows the intention to direct the course of their vessel to their own port (left).
It is the "Masters Salute", a salute to the Master of another vessel.
They intend to pass starboard to starboard side.
The sound signals that it is a sailing vessel underway when you hear one prolonged blast plus two short blasts every two minutes.
It is called a short salute and is how ships greet each other.
5 short blasts is a signal warning of imminent danger (or disagreement).
They intend to pass starboard side to starboard side.
They intend to pass starboard side to starboard side.