Steve,

Eloby had a gun (or guns, probably just one though) for protection in case a U-boat attacked her with its deck guns. This was a quite common tactic in 1915-1917, and the majority of British merchant ships were defensively armed by mid-1917.

The standard source for cargos and routes is "Lloyd's War Losses: The First World War." It does not list a cargo.

Best wishes,
Michael