A more thorough explanation:

NAUTICUM FENUS

Nauticum fenus is a type of loan used to finance the transportation of goods by sea. It is a loan made to a transporter of merchandise by ship, and is subject to an extremely high rate of interest because it does not have to be repaid unless the ship safely reaches its destination. This type of loan is both a loan and marine insurance. The rate, originally unlimited because of the risks of sea travel, was eventually fixed at 12%. The money loaned is pecunia trajecticia (money conveyed overseas).

An example of nauticum fenus would be a loan made to a merchant who is transporting goods by ship. The loan would be used to cover the costs of the voyage, and would be subject to a high rate of interest. If the ship safely reaches its destination, the loan would be repaid with interest. If the ship is lost at sea, the loan would not have to be repaid.

Another example would be a loan made to a ship owner to cover the costs of repairs or maintenance. Again, the loan would be subject to a high rate of interest, and would only have to be repaid if the ship safely completes its voyage.

These examples illustrate how nauticum fenus was used as a way to finance risky sea voyages, while also providing a form of insurance for the lender. The high interest rate reflects the high risk involved in sea travel, and the fact that the loan does not have to be repaid if the ship is lost at sea.