Master's authority to hypothecate ship

The master of the ship is the confidential servant or agent of the owners, and they are bound to the performance of all lawful contracts made by him, relative to the usual employment of the ship, and the repairs and other necessaries furnished for her use. . . . As, therefore, the master may contract for repairs and supplies, and thereby, indirectly, bind the owners to the value of the ship and freight, so, it is held that he may, for the like purposes, expressly pledge and hypothecate the ship and freight, and thereby create a direct lien on the same, for the security of the creditor. But the authority of the master is limited to objects connected with the voyage, and, if he transcend the prescribed limits, his acts become, in legal contemplation, mere nullities.