User blog comment:Master Sima Yi/Assassinews 19-07-'13 — Assassin's Creed: Brahman announced/@comment-5174994-20130901184045/@comment-1888015-20130901202436

You could access Brotherhood's contracts and Revelations' Mediterranean Defense from your main hideout and any other Towers/Dens you'd captured.

As I see it, I bet Edward could access a map or some plans aboard the Jackdaw to organize his fleet, while his cove hideout would have that function and be filled with other additional uses too.