The 101 meter long, 5350 ton Deneb was unloading containers at the port at Algeciras, Spain when it developed a strong list to starboard.   The vessel continued listing over until the Deneb was resting on its starboard side with the bow submerged.   Authorities placed booms around the vessel to prevent any oil pollution escaping into the harbour.  The Deneb had 118 tons of bunk oil and 26 tons of diesel fuel on board before the incident.   Reports state salvage will take up to one week to implement.   No reports of injuries.   An investigation into the incident is being conducted.