My father was a merchant seaman througout WWII. Here's a link to the Sailor's Union of the Pacific photo album. There are several nice pictures of preWWII and WWII merchant ships.
http://www.sailors.org
From here click on the history link and then the photo album link. You might also search for the webpages of the following US maritime unions:
Seafarer's International Union
National Maritime Union
Masters Mates and Pilots Union
Firemen Oilers and Wipers Union