Connor has more training to go through. Achilles is now putting him in charge of the vessel: The Aquila. Here Connor will learn about the sea and how to handle a ship. This is the final mission of Sequence 5
Take no damage before reaching Martha's Vineyard
Use the swivel guns to destroy two ships
Successfully brace during an attack on three occasions.
Head over to the marked cabin nearby the bay in the Davenport Homestead. There you not only encounter a ranting old man but the captain of the The Aquila. Talk with Mr. Faulkner after the cutscene on the dock to start things off properly and on the way toward the next mission.