Electronic Warfare Adaptive Spatial/Spectral Cancellation

Proposed for development is an escape trunk cofferdam that is made of a set of rigid (composite sandwich) cylindrical sectors joined by longitudinal sealing joints. The cofferdam is attached to the escape trunk's bubble skirt by an attachment ring whichallows the sections of the cofferdam to be staged below the hatch before it is opened. When the hatch is opened, the sectors are raised through the hatch. Then activation of a set of pneumatic longitudnal and circumferential seals locks the cofferdam inplace and makes it watertight. For passage of personnel, the composite cofferdam has an inner step and a folding step to reach outside the cofferdam. The proposed cofferdam is expected to be activated more quickly than an inflating-body cofferdam andwill be far more suitable for the rugged and frequently sharp-edged environment of a submarine. The material to be used for the cofferdam is also significantly less flammable than materials used typically for inflatables. The project proposed includesthe design of the sandwich shell, development of both mechanical and pneumatic type seals for comparison, and fabrication of a breadboard suitable for illustrating its fit and function dockside.The cofferdam proposed for development is based on existingcommercial products and offers a low-cost path to a set of long-lived cofferdams for the Fleet. This cofferdam can be applied to a number of applications in the construction industry.