door won't open on large boat

[yulog]

Okay now i'm stuck i'm about half way through the game, i'm at a point where i have 2 guards with me 1 of them is the guy whos girlfriends head was shot off on a boat, we are at a point where we go up stairs to a large boat, after i kill all the thugs the door on the far side of the boat does not open(i have checked you tube for a walkthrough and it shows the door opening) how do you get this door open?


any help would be much appreciated