Assassin's Creed 4's open world takes half an hour to sail across

It will take around half an hour to sail across the naval open world of Assassin's Creed 4: Black Flag, Ubisoft has told Eurogamer.

Game director Ashraf Ismail refused to say exactly how big the map was in relation to other Assassin's Creed games, however, since a lot of it is open water.

"We don't talk about it in terms of size, that would be a little bit unfair - there is a lot of ocean in the Caribbean. But it is the biggest game we've ever made," Ismail said.

"The story and narrative itself will last 15-20 hours, but we're hoping that people got lost in the Caribbean world, in the toybox we've created.

"It will take - [to sail] across the whole game world - maybe half an hour."

Large swathes of the map will be open ocean, but Ubisoft has stressed that you'll be able to spot multiple activities and side-missions on the horizon wherever you sail.

The game's fast-travel system has also been simplified to help with the larger map. You can now jump to any sync-point you've uncovered anywhere in the game world.

One casualty of Black Flag's size may be the series' expansion onto PlayStation Vita - begun last year with Assassin's Creed 3 spin-off Liberation.

Ubisoft decided not to develop a similar spin-off for Black Flag, despite decent sales of Liberation on the fledgling handheld. Ubisoft Sofia, the team that made Liberation, was instead put to work on the main Assassin's Creed 4.

"Liberation actually did very well - we're very proud of it," Ishmail explained. "Sales were fairly decent. But the focus for us was Assassin's Creed 4, for current-gen consoles and next-gen consoles.

"From a resource standpoint, the team that worked on Liberation is actually working with us on AC4. They're developing a specific part of the game for us. The amount of people working on AC4, Watch Dogs - that's a massive game - the focus within Ubisoft right now is on these two games, and then you have The Crew and The Division as well."