https://peertube.dngr.us/videos/watch/2b66e111-215e-485f-b595-7949eff5fc71 This “unclassified” 1974 US Navy film opens with a German submarine crew silently stalking and then firing upon an Allied vessel. During WW2, the film says, 47 major ships, 52 submarines, and countless lives were lost. The war also taught the Navy that close exposure to an underwater blast can severely damage a ship’s hull or propulsion systems, putting it out of commission. The film’s title, “Close Is Near Enough,” appears on the screen at mark 03:20 as the narrator echoes those same words. For this reason, the Navy established the Underwater Explosions Research Division (UERD) in 1946 to find way to strengthen ships’ hulls. The film shows footage of ships earmarked for the scrapyard being torpedoed as part of the test process before explaining what happens to a vessel during an underwater explosion (mark 04:45). We watch as a highly compressed gas bubble pulsates before creating a series of water plumes above the water line. The bubble causes severe pressure on any nearby object with the shockwave damaging a ship, even lift it into the air and slamming it back into the water. The film shows high-speed cameras being fitted into test ships to film damage (mark 07:30) with the captured footage shown and the details later analyzed (mark 11:00). The information ultimately will be used for new design techniques. There is a look of the UERD’s Submarine Shock Simulation Vehicle to evaluate the strength of submarines (mark 12:00) with additional footage of tests conducted using the vehicle as well as other ship explosions (mark 15:57) and experiments using simulated underwater mines (mark 18:00). 00:00 - 2:13 - Introduction to the impact of WWII on the U.S. Navy, highlighting the loss due to underwater weapons. 2:17 - 3:16 - Effects of underwater explosions, including how even near misses can severely damage ships by causing hull rupture or damaging vital equipment. 3:27 - 3:57 - Establishment of the Underwater Explosions Research Division (UERD) in 1946 to enhance ship and submarine design, using mothballed ships for experiments. 4:04 - 4:43 - Early research focused on improving hull resistance to underwater explosions 4:43 - 5:48 -How underwater explosions work, including the formation of gas bubbles, shock waves, and effects on ship structures. 5:56 - 6:19 - Details on how explosions beneath ships can cause additional damage by lifting and then dropping the ship into a void created by the explosion. 6:19 - 7:29 - Description of how experiments help in understanding weapon effects, identifying weaknesses, and improving future ship designs, emphasizing the need for reliable instrumentation. 7:33 - 8:59 - Use of high-speed photography and various sensors to capture and analyze the effects of explosions, highlighting the development of specialized equipment for these tests. 9:06 - 10:10 - Explains the setup for experiments, including the use of a barge for remote testing with all necessary facilities for prolonged research. 10:17 - 11:17 - Data collection and analysis process from the experiments, showing how this information leads to recommendations for ship design improvements. 11:21 - 11:56 - Focus on testing new hull designs for submarines, using both models and actual surplus submarines. 12:03 - Introduction of the Submarine Shock Simulation Vehicle for testing submarine equipment, allowing for comprehensive shock evaluations. 13:42 - Testing of surface ship equipment using floating shock platforms to simulate underwater explosion effects on various systems. 14:32 - Full-scale trials with ships from the mothball fleet, detailing the setup, execution, and aftermath of such experiments, including the environmental benefit of creating artificial reefs. 16:35 - Research on new materials and hull designs, including tests on high-strength steel and hull penetrations, with experiments on models and full sections. 17:54 - Testing of the Mark 105 hydrofoil minesweeper, showing how UERD evaluates equipment for use in combat scenarios like mine-sweeping in shallow waters. 18:34 - Discussion on the ongoing need for research due to evolving naval technologies and threats, emphasizing the division's role in defending against underwater threats. Motion picture films don't last forever; many have already been lost or destroyed. For almost two decades, we've worked to collect, scan and preserve the world as it was captured on 35mm, 16mm and 8mm movies -- including home movies, industrial films, and other non-fiction. If you have endangered films you'd like to have scanned, or wish to donate celluloid to Periscope Film so that we can share them with the world, we'd love to hear from you. Contact us via the weblink below. This film is part of the Periscope Film LLC archive, one of the largest historic military, transportation, and aviation stock footage collections in the USA. Entirely film backed, this material is available for licensing in 24p HD, 2k and 4k. 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