There is also AIS that shows ships around you. Recreational boaters use it all the time. However, military ships don’t use AIS . I have been boating in the Puget Sound, and all of a sudden a military ship or sub comes out of nowhere because they are cloaked. If the military is not going to use AIS, they also need to take precautions to avoid collisions.
believe that Naval vessels are exempt from the requirement to have AIS transponders.
Military vessels have AIS (They don’t turn it on because it drains the batteries)