The Admiralty Law covers “masters and members of a crew,” or a.k.a. “Seaman.” An employee will be classified as a seaman if his duties contribute to the function or mission of a vessel (or fleet of vessels under common ownership or control) in navigation and he has a connection to the vessel (or fleet of vessels) that is substantial in terms of both its nature and duration. As a general rule of thumb, an employee who spends less than 30 percent of his time in the service of a vessel in navigation will generally not qualify as a seaman. Contract employees who work back and forth between vessels not under common ownership are usually covered under the Longshore Act, not Admiralty Law. Employers should note that the terms “duration” and “nature” have been liberally construed by courts in favor of a finding for Admiralty Law coverage, and the 30 percent has not been defined in time so one full day could be enough.