I'm not familiar with FMS radios.

Maybe you meant FRS ( Family Radio Service). The hot air balloon pilots use
FRS radios to communicate with their ground crews here in the Oregon wine
country. These hand held radios often have scan functions built in, that's
how I heard the balloon pilots.

FRS radios can be used legally in the US to talk ship to shore, wheel to
anchor person, or boat to boat. However, they are line of sight and very low
power and not a substitute for a marine VHF in an emergency.

Rusty O