What causes the ship to move? Who serves on the crew of the ship on this leg of its journey? What force takes control of the ship at the equator?

1)The ship is moved by the 'spirit' when there is no wind.

2)The dead sailors serve as the crew of the ship.

3) The force of a spirit takes control of the ship at the equator. It is a spirit that certainly loved the albatross, possible kept it as a pet. The spirits goal is to make sure the Mariner is punished for the albatross' death.