In May 1792, American merchant sea captain Robert Gray sailed into the Columbia River, becoming the first recorded American to navigate into it. The voyage, conducted on the privately owned Columbia Rediviva, was eventually used as a basis for the United States' claim on the Pacific Northwest, although its relevance to the claim was disputed by the British. As a result of the outcome the river was afterwards named after the ship. Gray spent nine days on the river trading fur pelts before sailing out of the river.