Aids to Navigation Boat

The United States Coast Guard maintains roughly 145 Aids to Navigation Boats. These boats were designed primarily to serve within the inland waters of the United States. These vessels include TANB/BUSL/ATON/ANB ranging from 16 to 55 feet in length.
Most Aids to Navigation Boats of the United States Coast Guard are stationed with Aids to Navigation Teams (ANT). These are teams of boatswain's mates, machinery technicians, electrician's mates, and non-rated personnel that service small buoys, jetty lights and lighthouses.
Boats.
The AB-SKF and CB-ATON-M were apparently procured to replace the UTL (Utility Boat Light), which was a variety of non-standard small boat types.