Due diligence. Article III of the Hague Visby Rules and Hague Rules require the carrier to exercise "due diligence" before and at the beginning of the voyage to make the vessel seaworthy. "Seaworthy" means that the vessel must be physically sound, she must have proper equipment and supplies and efficient and sufficient manpower. The vessel must also be "cargoworthy", that is completely fit and safe to receive, carry and protect the cargo. Before the advent of the Rules, the common law obligation on the carrier was very strict and heavy. "Due diligence" was insufficient.