I copied a HAM I know at an audio site, his reply... While VHF FM is inexpensive and great for quality communications on the water with nearby boats or shore based VHF setups, HF SSB is a better choice for the high seas where other boats and the shore might be hundreds of miles away. I'm not a boater but I know how HF and VHF propagation differ.There are HF SSB digital modes (sitor, amtor, packtor, winlink, shipcom, etc) and services that provide email or chat-like communication over the air. The commercial services charge a fee while HAM radio operators will often use Winlink. Winlink is tied to the internet by shore based stations and the system allows email exchanges between a boater on the high seas and family and friends on land.And of course there's always HF SSB voice communications.There are also satellite phone based services via Iridium, Inmarsat, Globalstar, but these can be pricey.