The speaker begins with a vivid image of the lonely depths of the ocean, with nothing in sight but dark water. But then, in the last three words of the stanza, the speaker suddenly adds, "stilly couches she." ("She" refers to a ship.) It is as if a shipwreck had suddenly loomed up out of the empty darkness. Because the speaker delays introducing the ship, there is an element of surprise in the image (just as there was a great deal of surprise when the ship sank!).
This ship, of course, is the Titanic: the famous ocean liner that stunned the world when it sank on April 15, 1912. The poem was written just a month after the Titanic sank, and Thomas Hardy would have expected his audience to know that the Titanic was the largest and most luxurious ship in operation at the time—and that its makers had designed it to be "unsinkable."
Yet the poem signals immediately that, although it is about "the loss of the 'Titanic,'" it is not simply going to mourn the victims or celebrate the passengers' bravery in their final hour. It will examine the reasons why the Titanic sank and critique the motivations behind its construction.
To that end, the speaker does not refer to the individual engineers or laborers who built the ship. Instead, the speaker says that it was "human vanity" and "the Pride of Life" that "planned" the ship. The speaker suggests that people built the ship out of pride in their own abilities, especially their ability to conquer nature by creating a ship that the ocean couldn't sink. The ship's grand scale pleased the vanity of the builders, while its extravagant luxury appealed to the vanity of the wealthy passengers.
Now, however, the ship has become a symbol of pride and vanity gone too far. It was never "planned" that the ship sink "[d]eep" into the sea, and the poem implies that it was an act of hubris for human beings to think they could conquer the natural world. The poem is thus a critique of such pride and vanity.
The speaker strengthens this critique, and reminds the reader of how widespread these traits are, by using biblical allusions. The word "vanity" would summon to many readers' minds the Book of Ecclesiastes, with its famous line, "Vanity of vanities; all is vanity." The full verse reads, "Vanity of vanities, saith the Preacher, vanity of vanities; all is vanity. What profit hath a man of all his labour which he taketh under the sun?" (Eccl 1:2-3).
This verse insists that all things are, in one sense, useless or profitless. In particular, labor (like the labor of shipbuilding) does not profit humans they way they hope it will do. With the word "vanity," the speaker thus suggests that the Titanic does not represent the bad judgment of a few 20th-century individuals, but rather a universal human failing.
The phrase "Pride of Life" is a biblical allusion as well. It comes from 1 John 2:16: "For all that is in the world, the lust of the flesh, and the lust of the eyes, and the pride of life, is not of the Father, but is of the world." In this context, the "pride of life" refers to a proud, arrogant assumption of greatness, and the desire that others admire and applaud one's greatness.
Biblical commentators have connected this trio of failings to the three reasons why the forbidden apple appealed to Eve in the Book of Genesis: "the woman saw that the tree was good for food, and that it was pleasant to the eyes, and a tree to be desired to make one wise" (Gen 3:6). It was "pride of life" that made Eve desire to be as wise as God Himself, and this was partly responsible for the Fall of humankind into sin.
In connecting the Titanic's sinking to humanity's original fall, the speaker makes the ship a stunning symbol of human failing itself and reminds the reader that humans still destroy themselves through pride.