Adrienne Rich's poem "Diving into the Wreck" is about the poet's quest for freedom from her past, including lies she has been fed from society and history, including relationships with men, and especially including her own self-deception about who she is as a human being.
"First having read the book of myths" is the poet's summarization of all that history and books and experts and authorities have told her about life. She has read it, but she knows it is full of "myths," or interpretations of life which one must explore for oneself to test their authenticity and accuracy.
The loading of the camera refers to her preparation as she dives into the wreck of her life, a life which has been destroyed by others' lies and by her own acceptance of those lies. Now, however, she is setting out courageously and realistically to see what the truth is.
She checks the knife for sharpness, indicating that she is prepared this time, unlike in the past, to fight and kill the lies she faces, and/or to cut herself free from any entanglements which might try to drown her in those lies.
The outfit she dons to dive is black, unwieldy, and grave. She is encumbered by the outfit at the same time that she needs it to survive. In appearance, she is a kind of a monster as she dives, but she does not care any longer how she looks. She cares only about fulfilling her mission, finding her freedom from the past, and assessing what is left of herself and her life as she ventures into a liberated future.
She compares herself to Cousteau and his explorations into unknown and deep territory (the subconscious?), but, unlike Cousteau, she is quite alone. She knows that the kind of exploration she is doing, into one's psyche, one's past, one's very soul, can only be done alone, in fear and loathing, and that nobody can help.
The ladder is the symbol for changing from one level of reality to another, whether in dreams or in "real life" or in the sp...