A. Merchant mariners (aka merchant seamen) work on commercial cargo ships to and from US ports. During wartime, they’ve also served as auxiliaries to military and naval forces. To find information about your grandfather; begin by gathering clues from family and local sources, including hometown newspapers, and from the 1900 and 1910 federal censuses.
Next, request a search of Merchant Marine records at the National Personnel Records Center in St. Louis (314-801-9250, <archives.gov/st-louis>; click on Civilian Personnel Records, then Request Access to Records). Give your grandfather’s full name, his birth date and approximate employment dates. Since he was born more than 100 years ago, you don’t have to provide proof of his death. The Coast Guard’s National Maritime Center (202-493-1050, <www.uscg.mil/hq/g-m/nmc/web>) in Arlington, Va., holds merchant seamen records dating from the late 1930s, but isn’t likely to have records from your grandfather’s era.
You can find some Merchant Marine crew lists on microfilm at the National Archives and Records Administration (NARA) <archives.gov> in Washington, DC. Also look for these lists at the Family History Library <www.familysearch.org > and other research facilities. Before using these lists, try to identify US ports your grandfather might have sailed into. For names of ports with microfilmed crew lists, as well as information on other Merchant Marine records, see chapter 13 of the Guide to Genealogical Research in the National Archives of the United States, 3rd edition, edited by Anne Bruner Eales and Robert M. Kvasnicka (NARA).