Funny you should mention ancestry.com…. I’ve been thinking of subscribing for a spell to research someone on the maternal line (I inherited an item that might have been issued during the Great War). But I’d never thought of using it for the type of research you’re suggesting. Intriguing.
Also funny, in a dark way, but I lived a dozen years within driving distance of College Park, yet never took the time to pursue this. It’s human nature to put things on “the someday list” but like CCR sang, “someday never comes.”
Sounds like the bottom line is to write College Park, helpfully mention Record Group 24 & the correct box, ship name, date range, and ask for the Armed Guard logs for that ship and timeframe. Then stand by for their response. Is asking for the Armed Guard logs sufficient to cover the categories of documents that could be there? I understand it might be a rather large “document dump,” but I’ll sail that sea when I get there.
And for what it’s worth, you should give serious thought to tweaking that essay and posting on the site as a FAQ-style permanent item for anyone else who is looking for instruction. You’ve really laid out a great article there. I won’t be the only person who will ever benefit from it.