What do you think the role of a master is

The master is the person responsible for determinating the route and the speed of the ship.

Explanation:

He is the one who should always be aware of the situation, if the ship is getting to its destination on time or not. The route he is going shouldn't be changed. He is also responsible for the protection of documents and information. He is the one who tells when the ship should be sailed giving the right instructions. He leads the sailing and changes the route only if the law determines it.