Boarding enemy ships
 

Can it still be done? I've stopped playing the game for a while and decided to come back again. But when I was traveling the sea, I noticed that there aren't any enemy ships I can board. I remember seeing a flag on top of enemy ships indicating that you can hook the ship and then board it. Was/Is this an Unlimited Access feature?

No the flagships are still here and it wasnt a unlimted acess feature but for some reason they have compeltely disaperred except for a couple around PDF and of course the french and spanish ships.

Look around PDF, Cutthoart, Cangrejos, and Perdida for them

You've been gone a while if you're looking for the Bulwark and Greyhound Flagships at Devil's Anvil :)

Today - they don't exist. There is a EITC Light Gal and Light Frigate to board (the Frigate Starts at arounds KingsHead and heads to Outcast - the Gal starts behind Tormenta and heads to behind Port Royal)... but then everything goes big from there (both the Kingfisther and Baracuda War Sloops are at Perdida, The Man-O-War is at Kingshead, The Colossus is between Outcast and Tormenta and the even newer Undead French and Spanish Flagships are around Canjaros and Cutthroat) :)

If your look for a Navy War Frigate to board check the privateering islands.