This one long blast serves as a warning to other craft that there is an unseen vessel in the area. Be on alert!
The sound signal short-long-short is an optional, additional signal made by a vessel at anchor in restricted visibility. The signal may be made by such a vessel in addition to her required sound signal to give warning of her position and of the possibility of collision to an approaching vessel.Collision Regulations 35(g)
Two short horn blast from a vessel means that she is turning port and one short horn blast that she is turning starboard
The Vessel is turning to Starboard .
You are operating a motorboat. You hear one prolonged blast from the horn of another vessel. What should you do?
On seagoing vessels in restricted visibility a prolonged blast on the ships whistle means the vessel is making way through the water.
In fog, a pilot vessel is required to sound one long blast followed by two short blasts on its whistle at intervals of not more than two minutes. The long blast indicates the vessel's presence, while the two short blasts signal its role as a pilot vessel. This sound signal helps other vessels in the vicinity to identify the pilot vessel's location and intentions in reduced visibility conditions.
B
one prolonged blast
One prolonged blast followed by one short blast signals to a river lock attendant that a vessel is requesting to enter the lock. This sound pattern is a standard communication method used in maritime navigation to convey a specific intention. The prolonged blast indicates the vessel's approach, while the short blast serves to confirm the request for lock entry.
Vessel operators can alert the lock attendant of their request to transit through the lock by sounding one prolonged blast followed by one short blast
A vessel of more than 100 meters in length that is at anchor must sound a fog signal consisting of one long blast followed by two short blasts at intervals of not more than one minute. This signal alerts nearby vessels of its presence in reduced visibility conditions. The long blast lasts for about four to six seconds, while each short blast lasts for about one second.