The image below is centered on the New York harbor area. The small colored markers are ships. The image is a capture from a website which tracks the movements of over 50,000 vessels worldwide. I live in Iowa. We have barge traffic on the Mississippi River. But, it is seasonal and stops in the winter or dry weather.
If you live near a major world port, this web site will allow you to see hundreds of vessels. Click on the image to go to the site. Zoom in anywhere. Hover your mouse over a colored marker. Click on it to see more details and often a picture of the vessel. This is an excellent use of Google Maps and how it is linked to other databases such as the AIS system.
AIS is initially intended to help ships avoid collisions, as well as assisting port authorities to better control sea traffic. AIS transponders on board vessels include a GPS (Global Positioning System) receiver, which collects position and movement details. It includes also a VHF transmitter, which transmits periodically this information on two VHF channels (…) and make this data available to the public domain.
Because I am a land-lubber, I can’t offer any expertise about ships, navigation, harbors, etc. The site was very interesting, though. It is a good diversion from the usual negative news of the day.
There is a good FAQ section explaining the site and the methods used to track ships.
Click on the map and full steam ahead.