So, for example, in the famous case of Suisse Atlantique Societe d'Armament Maritime v Rotterdamsche Kolen Centrale [1967] 1 AC 361 (see also 11.3.2), where the charterparty contained no such express provision, the owners were fighting a lost cause in arguing that the spirit of the deal was that the charterers should make so many regular and punctual voyages across the Atlantic. According to the charter, the charterers were required to pay agreed damages (demurrage) if they exceeded the specified (lay) days allowed in port for loading and unloading the vessel; and this is precisely what the charterers did. The fact that they did this rather than pay the freight rates that the owners expected to earn on the contract, and the fact that they did this in self-serving response to the market conditions did not amount to a breach of contract. Certainly, this was a self-interested performance of the contract; it was not co-operative; but it could not be corrected by an implied term.