Each applicant for an original ``Tankerman-Assistant'' endorsement who has not presented the required service on tankships or self-propelled tank vessels shall present a certificate of completion from a course for Familiarization with DL or LG Tankships or from a tanker-familiarization course appropriate to the endorsement applied for, and approved by the Commandant. The date of the certificate may not be more than 5 years earlier than the date of application.