AIS

Every ship, live

AIS is a radio that every ship broadcasts — position, speed, course, and name. Beacon plots them all on one screen, so you can see the traffic before it sees you.

What you see

vessel    name + type + draft
position  live to the second
cpa       closest point of approach
alarm     if a ship is closing on you

Why they matter

At night, in fog, the AIS screen is the most honest thing on the bridge. A ship is not a dot — it's a decision you'll need to make.