"The Convergence of the Twain"
by Thomas Hardy

This poem focuses on the vanity of the Titanic. The ship was known for the opulence and extravagance pictured in lines 8 and 10 in the description of the mirror and the jewels. However, after the ship sank, no one but the "dim moon-eyed fishes" and the sea worms are can even see the grandeur. Because no one can even see it anymore, the speaker says that the  vanity of the ship is pointless. No other creatures care about all of the jewels and ornate furniture. The worms just crawl over it and the fishes can't even see it.
This poem is meant as a lesson for us that human vanity is short and transient. It will eventually become old and useless just like the Titanic. The ship's vanity was short-lived because it sunk on its maiden voyage. However, it will spend an eternity under the sea where its vanity is useless. Basically, human vanity is pointless because the opulence and grandeur will fade.