All submarine movement is to written orders, this will enable simutaneous movement of all submarines. These orders have been purposely kept simple, to ensure that more time is spent playing the game, rather than writing orders.
Submarines can change speed, either be accelerating, allowing the submarine to slow itself down, or reversing engines.
Submarines with two screws will have an advantage if they lose one, but the additional noise that two screws make will make it easier to detect.
A submarine which has acquired a target, or is maintaining acquistion, can move after the target submarine has moved if the target submarine is in their 90º frontal arc.
Optional Rule: Rather than just allow following submarine to move, the commander can see where the enemy submarine moves to, and then must still write orders for movement.
As might be expected there will be situtations, when playing with a lot of submarines, where submarines following one submarine, will be followed by another, who will be followed by another, etc... in these situations use common sense, and where applicable, roll a dice to see who moves first.
Submarine movement does not require the use of command points.