The Shakespeare.

It happens often. I beg to believe that inadvertently, a ship is referred to as for instance: “The MV Nisshin Maru”, when whaling vessel MV Nisshin Maru sounds just right. There is indeed no need for the definite article “the” before a ship’s name, with the exception of the article being already part of the name itself. For example, if the container ship “Maersk Batur” enters a port, it is better to say “Maersk Batur” entered port, rather than “The Maersk Batur entered port”.
The grammar behind it is that the definite article is not normally used with names. It is very much as writing that the Shakespeare wrote “Hamlet”.