Hello Graham, I haven't any American mariners, so USA records are totally a foreign country to me, but a quick look says "Yes, they do have Official Numbers and they appear to have started c. 1866." Here's a site to skim re vessel documentation:http://www.archives.gov/research/maritime/vessel-documents.html Annual lists of ships here:http://www.ibiblio.org/hyperwar/AMH/USMM/Annual_List/ Regards,Adi   From: Graham Read via <mariners@rootsweb.com> To: "mariners@rootsweb.com" <mariners@rootsweb.com> Sent: Thursday, October 22, 2015 6:57 AM Subject: Re: [MAR] Packets and Employment of European Seamen - was Re: Migrant ship GARRICK 1853 Since Jefff originally asked about an Official Number for the Garrick, and since 'we' have established pretty well that she was an American ship, this raises the question 'What do we know about American Official Numbers ? Then, are there any? From which dates?  Can you look them up?  Where? On-line? Is there some knowledgable KP out there who could inform us? or at least me.