water traffic control
A tower, post, or operational center where controllers monitor and direct ships or other waterborne traffic.
A water traffic control center is a tower, post, or other space where waterborne traffic is monitored and controlled. This includes maritime traffic, river traffic, harbor traffic, etc., and all vehicles involved including ships, boats, hovercraft, jetfoils, rafts, barges, etc. Controllers in these locations optimize the flow of waterborne traffic and prevent accidents and misroutings.
This usage does not apply to lighthouses, buoys, or automated or unmanned objects which serve as ship guidance markers rather than traffic control centers.
The controlled traffic can use rivers, harbors, or open maritime routes. The type includes boats and other waterborne vehicles rather than only large seagoing ships.