The Patino auxiliary oiler and multiproduct replenishment ship entered service with the Spanish Navy in June 1995. The 17,045t Patino (AOR), the 13,600t Marques de la Ensenada fleet tanker (AORL) and the 2,272t Contramaestre Casado transport ship (AP) are the three major auxiliaries, i.e. tanker and supply ships, in the Armada Espanola.
Replenishment ship was the first thought in my head upon seeing the photo. Still a warship.