AS above, most marine radios are good. But the main thing to know is the signal is line of sight. A typical deep v boat may have an antenna about 5 ft off the water. That would give you a transmission of about 3-4 miles to a typically equipped boat. A taller boat with a taller antenna would transmit and receive at a further distance. If you are concerned more about safety recognition by the Coast Guard, then a radio that accepts a MMSI number is required. This is just a little information. I would suggest that you do research for what use you want it for.