I was able to obtain ship rosters and Armed Guard voyage reports a few years ago through the National Archives. Send a letter (no email was available)to :

Modern Military Records
8601 Adelphi Road (Room - 2400)
College Park MD. 20740-6001

Give them as much information as you can. They'll write back a tell you what they have. At the time, it costs .50 per page.

Good luck