It is the "Masters Salute", a salute to the Master of another vessel.
You need to transmit the Morse letter D (-..) with either a fog horn or hitting a bell every 2 minutes. Long blasts need to be 3 times as long as short blasts. The space between blasts is as long as the duration of a short blast. So the sequence goes like this: Blow the horn or hit the bell for 6 seconds, wait for 2, hit it for 2 seconds, wait for 2 seconds, and hit it again for 2 seconds.
I intend to pass you on the starboard(right) side
Sailboat
you better get off that ship!!Two short blasts means that the vessel intends to leave you on it's starboard side. If you are in international waters it means " I am altering my course to port"
Rules of the Road. Rule 35, Sound Signals in Restricted Visibility. (C) A vessel not under command, a vessel restricted in her ability to maneuver, a vessel constrained by her draft, a sailing vessel, a vessel engaged in fishing, and a vessel engaged in towing or pushing another vessel SHALL, sound at intervals of not more than two minutes three blast in succession, namely one prolonged followed by two short blast.
passing on the port side from behind
There are particular sound signals that are to be used when you first get underway. One prolonged blast signifies that you are about to get underway. If you are going to make way in reverse, you need to signal an additional 3 short blasts.
It has several meanings depending on circumstances.A vessel not under command or restricted in its ability to manoeuvre, or constrained by her draught, or engaged in fishing, or towing or pushing, or a sailing vessel.
In the maritime environment, it mean several things: 1. In restricted visibility it means the vessel is making way through the water. 2. A vessel approaching a blind bend in a river can sound one prolonged blast on the ships' whistle to alert any other vessels to its presence, if another vessel is nearby then they will respond with one prolonged blast on the ships' whistle.
4 short blasts are the letter H is morse. On the River Clyde in Scotland a local bye law allows it to be signalled by a vessel going astern from a berth, generally a paddle steamer, indicating that it is going astern, it has difficulty in manoeuvring and warning other vessels to keep clear.
In the maritime environment, it mean several things: 1. In restricted visibility it means the vessel is making way through the water. 2. A vessel approaching a blind bend in a river can sound one prolonged blast on the ships' whistle to alert any other vessels to its presence, if another vessel is nearby then they will respond with one prolonged blast on the ships' whistle.