I have found online information that SS SAN BRUNO was built by an Irish shipyard, Workman Clark and Co. in Belfast, Northern Ireland about 1919. She was owned and operated by the United Fruit Steamship Company prewar (and postwar?) so very possibly she was a "banana boat." According to
http://www.unitedfruit.org/great-white.htm, SAN BRUNO was part of United Fruit's fleet as early as 1919. She was a refrigerator vessel so during the war she might have carried fresh or frozen food. SAN BRUNO is mentioned in passing at
http://www.shipscribe.com/usnaux/AF/AF24.html, which describes and has a photograph of a sister ship. SAN BRUNO also carried as many as 12 passengers, presumably prewar.
Ron Carlson, Webmaster
Armed Guard / Merchant Marine website
www.armed-guard.com