In the war the Entente Allies defensively armed their merchant ships, generally with a single naval gun on the stern. The USA was neutral until April 1917, but from September 1914 its Department of State allowed an armed merchant ship of a belligerent country to use US ports on condition that she was armed with no more than two guns, they were not more than calibre, no guns were mounted on the forward part of the ship, her cargo excluded war materiél, and her passengers as a whole were not suitable for military service.
