What must a captain do before departing if they have not used the full borrowed amount?

The correct response indicates that if a captain has not utilized the full amount of borrowed funds, they must return the excess amount of money. This requirement stems from the obligations of managing funds responsibly in maritime commerce. When a captain borrows money, it is often tied to specific purposes, such as covering operational costs or fulfilling contractual obligations during a voyage.

Returning any unspent funds demonstrates fiscal responsibility and adherence to contractual terms. It helps to maintain trust with financial backers and ensures compliance with laws or agreements governing maritime finance. Maintaining good standing is crucial in maritime operations, as it influences future borrowing capabilities and partnerships.

The other options do not directly address this essential aspect of managing borrowed funds. Filing a report with the shipping authority or notifying other owners lacks relevance to the direct financial responsibility of returning unused funds. Preparing to repay in full at the next port may imply a future obligation, but it does not address the immediate requirement to return the excess funds. Thus, the focus on returning the unspent amount aligns with best practices in maritime commerce management.