I have been thinking this as well since seeing the story of the Italian ship. Detailed plans of each deck would likely be a) hard to acquire or b) hard to carry around in a format that is compact, readable, and waterproof. However even so, if I was to spend a week on such a boat I would take some time familiarizing myself with the deck plans if I could find them.

I was taught that "time spent in recon is time well spent".