McGrath, I don't think that your suggested line about the captain can be correct.

"The captain of the Mexico, as you may understand" is fine as far as it goes, as an introduction to some description, perhaps, but what is it about to tell about him? That he was tall? That he was aboard? That he couldn't swim?

The verse then would abandon the good captain as the subject of a sentence, but without a verb, and would go on to deal with the crew instead.

Dave Oesterreich