After two major collisions with substantial loss of American lives between US Navy destroyers and merchant ships, many of us went to websites that provide histories of the movements of the ships in the area up to the minute of the collision. Using the AIS transponders that are on all of the commercial vessels, and some of the recreational vessels, you can clearly see the paths of the vessels heading in and out of some of the most constrained and confusing waterways in the world.

AIS, or Automatic Identification System, is one of the most significant marine safety innovations in a decade. Required on much of commercial traffic and available (and highly recommended) for recreational boats and even personal gear, AIS devices can serve to track other boats, alert to risky situations, and even help locate a navigational aid or crew overboard.