High-speed photography and precision instrumentation are vital to examining the highly transient loading and response of structures to underwater explosion (UNDEX) phenomena. This paper presents a description of the photographic equipment and technology that have been specifically developed for examining large-scale UNDEX events in open water. Open water blast photography imposes several challenges over laboratory settings, not the least of which is the extremely hostile shock environment that very expensive camera equipment must be exposed to, plus the additional difficulty as a result of working on the water. Successful underwater photography has three primary prerequisites: 1) protection of the photographic equipment from the severe shock; 2) adequate lighting; and 3) clear water. The special design features for shock-hardening the separate enclosures for the camera and flash-bulb lighting units are detailed, and shock qualification tests results are presented. The chemical treatment employed to clarify the water to permit successful U/W photography is also described. In many cases, large bodies of water cannot be treated in their entirety and a method for isolating a more manageable volume of water is required. The approach to this problem as adopted by DSTO, Australia is presented.
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