Comunication

For modern mariners, the foundation tool is VHF, perhaps the most dependable means over distances of less than 20 miles. Good for bridge openings, talking to marinas, and summoning help. For communicating with friends, it's been largely replaced with cell phones and internet services, even though those can be less than reliable even in coastal areas. Off-shore we transition to SSB and sat phones.

But there are other ways. These messengers were used by Bernard Moitessier during the first round-the-world singlehanded race, describe very well in A Voyage for Madmen.

Very traditional, rather like his yacht. Dependable and thrifty?

For express service, he chose a multihull design.

 Most of us would judge him a bit mad by this point in the race, but for him, this seemed to be his "normal." He was simply well adapted to life alone, at sea, and less so for life with people ashore.