The best thing to do would be to get a nice large crew of people that you trust, and pick who's going to do what. If your friend wants to sail he can, or if he thinks someone else should sail that can work, too. The more people the better for the boss battle. You can always ask for help in
this thread.
Also, one thing that helps is to always have the boat parallel to the bridges. Of course you'll have to sail perpendicular to them to get to them, but being parallel allows a whole set of gunners to focus on the bridges.