0 Under way using engine

A vessel is considered to be underway when it meets the following criteria:

  • It is not aground
  • It is not at anchor
  • It was not attached to a dock, the shore, or any other stationary object.

This navigational status message refers to machinery vessels in motion.

1 At anchor

A vessel is at anchor when it is held in position by an anchor on the bottom of a body of water, thus preventing a vessel from drifting away from the desired position (e.g. waiting for a berth, heavy weather, receiving fuel oil, loading, and unloading cargo, for maintenance purposes). The "at anchor" state begins when the anchor hatches firmly hit the seabed and the ship is held in a certain position. While the vessel is considered to be "underway" as soon as the anchor is weighed or towed on the seabed. The vessel is not fixed at a dock, which is called moored.

2 Not under command

The term “not under command” means a vessel which through some exceptional circumstance is unable to manoeuvre and is therefore unable to keep out of the way of another vessel.

3 Restricted Manoeuvrability

Manoeuvring characteristics include turning, yaw-checking, course-keeping and stopping abilities of the vessel. The term "restricted manoeuvrability" means the vessel is unable to keep out of the way of another vessel. It also includes:

  • A vessel engaged in laying, servicing, or picking up a navigational mark, submarine cable or pipeline.
  • A vessel engaged in dredging, surveying or underwater operations.
  • A vessel engaged in replenishment or transferring persons, provisions or cargo while underway.
  • A vessel engaged in the launching or recovery of aircraft.
  • A vessel engaged in mine clearance operations.
  • A vessel engaged in a towing operation such as severely restricts the towing vessel and her tow in their ability to deviate from their course.

4 Constrained by draught

A power-driven vessel which is severely restricted in the ability to deviate from the course it is following because of the draught in relation to the available depth and width of the navigable water.

5 Moored

Securing a vessel at a pier or elsewhere by several lines or cables to limit the movement.

  • Multi-Buoy Moorings (MBM), conventional buoy moorings – A facility whereby a tanker is usually moored by a combination of the ship anchors forward and mooring buoys aft and held on a fixed heading.
  • Single Point Mooring (SPM) – A facility whereby the tanker is secured by the bow to a single buoy or structure and is free to swing with the prevailing wind and current. Three types are common: Catenary Anchor Leg Mooring, Single Anchor Leg Mooring and Turret Mooring.

6 Aground

A vessel that ran aground onto or on a shore, reef, or the bottom of a body of water.

7 Engaged in Fishing

The term ”engaged in fishing” means any vessel fishing with nets, lines, trawls or other fishing apparatus.

8 Under way sailing

A vessel is considered to be underway when it meets the following criteria:

  • It is not aground
  • It is not at anchor
  • It was not attached to a dock, the shore, or any other stationary object.

This navigational status message refers to all ships using wind power.

9 Reserved for future amendment of Navigational Status for HSC (high-speed craft)

10 Reserved for future amendment of Navigational Status for WIG (Wing-in-ground craft)

11 - 13 Reserved for future use

The AIS standard describes the navigational status as a number. This number is transmitted using 4 bits. With 4 bits numbers from 0 to 15 can be displayed (2^4 possibilities). Because not all 15 statuses are assigned at the moment, there are areas which can be reserved for the future and can be reassigned if necessary.

14 AIS-SART is active

An AIS-SART (Automatic Identification System - Search And Rescue Transmitter) is a device that sends a position-based emergency message based on the Automatic Identification System (AIS) protocol. The position and time synchronisation of the AIS-SART is done by a built-in GPS module.

The position of the lifeboat in distress or of a person with an AIS-SART in their life jacket is transmitted via the AIS receiver or AIS transmitter/receiver to the PC or to the chart plotter as a serial protocol and is then visible on the plotter or on the PC. This allows any ship with AIS on board to initiate an immediate rescue operation, which significantly increases the chances of survival.

15 Undefined = default (also used by AIS-SART, MOB-AIS and EPIRB-AIS under test)

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