AIS

Question 1

What is Ais

Answer 1

Automatic identification system

Maritime mobile VHF broadcast system that can send both static and dynamic ship information, such as MMSI, call sign, Position, Course and speed to other AIS transponders and base stations.

It is a additional navigation aid and supplements primary means of navigation.

Question 2

Which vessels does AIS apply

Answer 2

All passenger vessels
All vessels over 300gt on international voyage
All cargo ships over 500gt

Question 3

What are the primary uses of Ais

Answer 3

VTS
Aid to navigation
Search and rescue
Assist in Collision avoidance but always adhere to COLREGS

Question 4

What is class A Ais

Answer 4

Required on vessels over 300gt
Typical sytem has; 1 vhf antenna, 3 vhf receivers, Gnss input, additional shipboard data inputs and output of info to ship displays and a user input.

Minimum mandatory requirements are an manual keyboard display (MKD)
Approved by IMO

Question 5

Type of info inputted and sent on AIS

Answer 5

Static: information entered on installation. Info can only be changed with approval from master. Type of ship, length and beam, MMSI,
Call sign, IMO number, Location of GPS antenna.

Dynamic: info that is provided by the ships instruments, Position with accuracy indication, Position time stamp, course over ground, speed over ground, heading, Navigational status, Rate of turn

Voyage: info inputted by operator regarding voyage. I.e. type of cargo, Destination and ETA draft, Route plan, Short safety related messages.

Question 6

Errors of Ais

Answer 6

Not provide full picture of situation, some vessels are not fitted with Ais and others i.e. Warships might not have them on

Only as accurate as the info inputted

Question 7

What are the two types of AIS AIDS to navigation

Answer 7

Physical bouy, beacon with an Ais transpomder which send information regarding that beacon.

Virtual navigation mark. Authorities will send out a vhf Ais signal that will display on an Ecdis or radar display which will provide additional information regarding tides, weather NAV hazards, with out having an actual fixed bouy.

Question 8

Advantages of AIS

Answer 8

1. Small vessels which may not be picked up on radar if fitted will be displayed.
2. Not effected by bad weather and heavy seas.
3. If coming around an island or blind bend it can provide advanced notice of oncoming vessels
4. Very fast updated information of the other vessel.