Check out all the ways that things change in "Diving into the Wreck." First we watch the speaker put on fins, change into a diver. Then we enter the water, a whole new world, with new rules. Petty soon, we don't even know who our speaker is. Is our speaker a man or a woman? Is it even human? How do we deal with changes in our lives? When things change, when our environment shifts, do we become different people? These are tough questions, but important ones too, and Rich is partly using this poem to sort them out.
By the end of this poem, the speaker is not just a person who went scuba diving. In fact, he or she has become many people, a man, a woman, a sea creature, a representative of all people who have ever experienced disaster.