Marine safety?
Marine VHF.
Just to talk to each other any old FRS type thing will do well over water.
I use a couple of Uniden marine VHF radios. When alone I leave the non water proof one in the car so should my wife or anyone with keys be looking for me they have a shot at getting me.
With the Marine VHF. I also get Harbour Traffic updates when crossing water ways, weather updates, sea going advisories, can call the harbour master and ask silly questions and can call for help or report an issue. You need a license in Canada, (I have one but god knows where, they are good for life and mine is dated about 1977) . If you are sensible the license thing will never come up.
For talking about a group in line of site up to say 2 miles and FRS radio in a zip lock bag or a condom will work well.
Alex