The prefix is considered part of the ship’s name. HMS is short for His/ Her Majesty’s Ship; HMAS is short for His/ Her Majesty’s Australian Ship; USS is short for United States Ship; ARA is short for Armada de la Republic Argentina; etc. Not all nations use a prefix, Hitler’s Germany being one of them, which is why the German ships are referred to simply as 'Bismarck’ and 'Prinz Eugen.’
A ship’s name (including the prefix where applicable) is a proper noun, same as the name of a city, state, or person. As with all proper nouns, it refers to a specific, unique item, and it is always capitalized. So you so should not write “the HMS Prince of Wales†any more than you would write “the Orlando, Florida†or “the Uncle Billâ€.
However, when using the ship’s name to refer to the whole class, it is no longer a unique proper noun. So you would write “The HMS King George V Class battleships†when referring to the whole class of ships, but “HMS King George V†when referring to just that specific ship.
And if you precede the name of the ship with a common noun being used as an adjective that describes the type of ship, you would use “theâ€. So you would write “the battleship HMS Prince of Wales†or “the cruiser Atlanta,†but never “the battleship the HMS Prince of Wales†or “the cruiser the Atlanta.â€
So, in short, when using the ship’s name as a proper noun don’t use “the.â€
Oh, by the way, Bismarck was not scuttled off Uruguay; it was sunk by British warships and aircraft in the Atlantic. It was the German armored ship (often referred to as a‘pocket battleship’) Graf Spee that was scuttled in Uruguay. I have some pics of us exploring that wreck also, but the underwater shots did not come out due to zero visability in the muddy water.
As for not wanting anyone to mess with the wrecks, particularly HMS Prince of Wales and HMS Repulse, it is because the ships are war graves, filled with human remains and protected by international law. However, many folks like to grab souvenirs or worse yet plunder pieces of the ships for sale on the black market. This is the equivalent of going into Arlington National Cemetery with a shovel looking for things to dig up, take from the graves, and sell on EBAY. But unlike Arlington, there are no guards on undersea war graves, so I refuse to post the GPS coordinates to the wrecks and assist the people who want to loot them.