French hospital ships often part of escorted convoys according to the Kriegsnachrichten of the Chef des Admiralstabes der Marine dated Berlin 18 August 1917

An item reported that according to German officers French hospital ships in the Mediterranean often steamed with merchant ships as part of convoys escorted by torpedo boats. In the night were the distinctive emblems of the hospital ships not illuminated.

Source

Bundesarchiv RM-40-622