From the contractual context, it sounds like it is an entity rather than the personal contractual liability of the Captain or Shipmaster, this is why I have chosen Shipmasters. But you will have to evince this from the other contractual provisions or by looking at the parties to the agreement and how they have been named.
This is what I found in wikipedia:
A sea captain, ship's captain, captain, master, or shipmaster, is a high-grade licensed mariner who holds ultimate command and responsibility of a merchant vessel.[1] The captain is responsible for the safe and efficient operation of the ship‍—‌including its seaworthiness, safety and security, cargo operations, navigation, crew management, and legal compliance‍—‌and for the persons and cargo on board
Howver the Capital or Shipmaster is liable for legal compliance. So, the choice is yours.