It would be helpful to know more about your location, nationality, cruising plans, etc.
In general, every country has it's own regulations
and requirements for obtaining amateur and ship licenses. Ship licenses are generally good for operating in countries other than the one where it was issued. However, for ham radio
operation you need to obtain a license
from many countries before you can operate in their waters (e.g., Bahamas
, BVI, and many, many others). Some countries have reciprocal agreements which will allow you to operate a ham station without need for additional permission. For example, U.S.-licensed hams can operate in Canada
using their own callsigns plus a suffix indicating Canada
. Ditto for Canadians in the U.S. Others will grant you a temporary license
for operation in their waters based on your "home" license.
Lists of country requirements for ham licensing can be found on the ARRL website, ARRLWeb: ARRL Home Page
Since the overall picture is quite complex, it would be good to think about what you will need (marine or ham or both) and where you will need to operate (specific countries), THEN do the research
to find out what you'll need to be legal