This is from an earlier posting I wrote:
As for your question about naming of a vessel, the general rule applied by ship registries of the world is that the suggested name cannot be the same as or similar to that of another vessel registered in the ship registry of the intended flag state. This also means that two vessels flying different flags may have the same name. The distinction will be made by different home ports and of course by unique IMO numbers and call signs.
Another rule is that the name of a vessel "cannot be offensive to members of the public" as the expression is. One well-known case is of course Tits (now Samax). This name was obviously considered acceptable to the ship registry. What is "offensive" will be decided case by case by the ship registry in question. I suppose suggested names very rarely fall into this category.
The name is chosen by the owner of course and you cannot expect a world copyright on your name unless the name is protected otherwise as a brand/trademark or company name.
When it comes to renaming of yachts this is also from an earlier posting:
On the other hand I don't think a project name (like Faberg