The law with regard to the contract of affreightment is, of course, a branch of the general law of contract. The rights and obligations of the ship-owner and the freighter depend, as in the case of all parties to contracts, upon the terms of the agreement entered into between them.

The law, however, interferes to some extent in regulating the effect to be given to contracts. Certain contracts are forbidden by the law, and being illegal are therefore incapable of enforcement. The most important example of illegality in the case of contracts of affreightment is when the contract involves trading with an enemy.

The law interferes again with regard to the interpretation of the contract. The meaning to be given to the words of the contract, or, in other words, its construction, when a dispute arises about it, must be determined by a judge or court. The result is, that certain more or less common clauses in contracts of affreightment have come before the courts for construction, and the decisions in these cases are treated practically, though not perhaps quite logically, as rules of law determining the sense to be put upon certain forms of expression in common use in shipping contracts.

A third way in which the law interferes is by laying down certain rules by which the rights of the parties are to be regulated in the absence of any express stipulation with regard to the matter dealt with by such rules. This is done either by statutory enactment, as by that part (Part VIII) of the Merchant Shipping Act 1804 which deals with the liability of ship-owners; or by established rules of the unwritten law, the common law as it is called, as, for instance, the rule that the common carrier is absolutely responsible for the safe delivery of the goods carried, unless it is prevented by an Act of God or enemies of the Queen.

These rules of law, whether common law or statute