This is the place. And I am here, the mermaid whose dark hair streams black, the merman in his armored body.
The speaker finally reached the wreck and become part of it. Calling herself both the mermaid and the merman could suggest that she feels connected to different sides of human experience, not limited by gender.
I came to explore the wreck. The words are purposes. The words are maps.
This part might mean that the speaker’s goal is to truly explore and understand the wreck, not just read about it. The “words” could represent stories or explanations that guide her, like maps, but she still needs to see the truth for herself.
I go down. My flippers cripple me, I crawl like an insect down the ladder and there is no one to tell me when the ocean will begin.
This might describe how the she feels awkward and alone while going deeper into the sea. The image of crawling “like an insect” could suggest weakness or discomfort.