AIS (automatic identification system) transponders put out a signal that describes your boat and what it is doing to other ships. It also receives the same information from any other ship within range. Commercial ships are now required by most flag countries to carry a transceiver—for big ships it is a class A—so most large vessels will show up as well as a good proportion of smaller ones.
To continue reading this article or issue you must be a paid subscriber. Sign in
Subscribe to Practical Sailor
Get full access to Practical Sailor - over 4,000 articles - for just $34.
Subscribe today and save 42% off the annual rate.