Fully agree with RVDT
Coasts with many islands and rocks can be real challenge to any locator from standard
old 121,5 and on.
Sea environment and high waves is another problem.
On land GSM location from another aircraft can be useful technology.
On sea only sort of permanent tracking network can gain some time to rescue services.
Technologies like FR24, FLARM, OGN in some kind of voluntary networks can bring
some benefits, hopefully.