Does anyone know what is the meaning of four short blasts on a ship's horn?

In: Sailing [Edit categories]

Answer:

Pilot vessel engaged in pilotage duties

Related answers:

What is the meaning of five blasts on a ship's horn? Danger
What is the meaning of 1 short 1 long and 1 short horn blast from a ship? At Anchor, It is used addition to the required rapid ringing of the bell for five seconds (not to...
What is meaning of three long blasts on ship's horn? It means "Man overboard". Note: 1 long blast = 5 or 6 seconds 1 short blast = 1 or 2 seconds...
What do five short blasts of a ships horn mean? Five short blasts means danger !

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