It struck me on this read, that when Captain Wentworth takes up the navy list, it is not unlike Sir Walter taking up his Book of Books back in Ch. 1

The girls were now hunting for the Laconia; and Captain Wentworth could not deny himself the pleasure of taking the precious volume into his own hands to save them the trouble, and once more read aloud the little statement of her name and rate, and present non-commissioned class, observing over it, that she too had been one of the best friends man ever had.

...particularly the way it is called 'the precious volume'. He's read it over more than once, obviously, and knows exactly what is to be found in there.