You will definitely have to register, document or some way as specified by the country of your choise, get some sort of legal
paperwork for your boat. Otherwise you will encounter major problems in almost every country in the world.
Just like you have to have a passport for yourself you also have to have some sort of legal paperwork for the boat. Mainly I think to show that you own or have legal right to be aboard that boat.
So, unless you plan to go to sea and never enter a country, then yes.