I am frankly AMAAAAZED at the question, and at some of the responses.
There are literally HUNDREDS of hams on cruising boats, hundreds of posts on this Board, CruisersForum, SSCA, and others pertaining to the use of ham radios on boats, and dozens of articles in ham radio magazines and in sailing magazines. There's even a book or two.
Yes. Ham radio on boats is very much alive, and the community is growing. There are ham exams each year at cruiser's gathering spots (like Georgetown in the Bahamas and Marathon, FL) which do license exams for new hams, and dozens of cruisers pass them. We just completed a ham course at the Capital Yacht Club in Washington, DC and signed up a bunch of new hams.
Two of the most active ham nets are:
1. The Maritime Mobile Service Net which operates on 14300 kHz most of the day, followed by the Pacific Seafarers Net; and
2. The Waterway Net on 7268 kHz each morning beginning at 0745 Eastern time (been operating daily for well over 40 years).
A list of ham nets -- as well as marine SSB nets -- can be found here:
Net / SSB Frequencies
As to equipment, antennas, and ground systems there are literally dozens of options. Many of them have been discussed on this and other Boards.
Your setup aboard can be very simple and inexpensive, or as complex and expensive as you want it to be. The only limit is your own ingenuity.
Good luck to you, and by all means go for it!