The periscope of the American submarine USS Dallas cuts through the surface as HMS Illustrious sails past in the morning haze.
HMS Illustrious, RFA Fort Victoria, RFA Fort Austin, USS Bulkeley and the American Los Angeles Class Submarine USS Dallas took part in a joint anti submarine exercise in the Middle East.
The aims of the exercise is to develop maritime interoperability by exercising Anti-Submarine Warfare tactics with US allies in the challenging sonar environment of the warm and shallow waters of the Gulf region.
The exercise was broken down into three phases. The ships and submarines initially tested acoustic and non-acoustics sensor performance against known positions, gaining useful real life data for the region.
The second phase relied on the ships escorting HMS Illustrious as the Mission Essential Unit (MEU) along a passage whilst evading detection and simulated torpedo attacks by USS Dallas.
In the final phase USS Dallas tried to locate and destroy RFA Fort Austin as the MEU, in a holding box which simulated an anchorage, as the UK and US naval ships provided protection. Additional helicopter support to the ships was ably provided by the Anti-Submarine sonar dipping Merlins embarked in HMS Illustrious and USS Bulkeleys Seahawk, with Westminsters Mark 8 Lynx helicopter providing an additional surface search and weapon carrying capability.