An abandoned anchor punctured the tanker Athos I and spilled roughly two hundred sixty-four thousand gallons of crude oil into the Delaware River. The ship’s owner and the United States sought cleanup costs from the charterer under a safe-berth clause requiring the charterer to select a berth where the vessel would remain safely afloat. The Supreme Court held that the clause was an express warranty of the berth’s safety, not merely a promise to exercise due diligence. The charterer therefore could be liable even without negligence in selecting the berth. The Court affirmed the judgment interpreting the clause, while explaining that the contractual text controlled the allocation of risk. Justice Thomas dissented, arguing that maritime trade usage created a factual question about whether the parties intended a due-diligence obligation rather than an absolute warranty.