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water to cavitate, thus forming a bulk cavitations zone. The water refraction near the surface wave has a vertical velocity. The midget submarine is with- in the cavitation zone and was buffeted by a vertical motion, exposing the con- ning tower and its contra-rotating pro- pellers. The magnitude of the vertical velocity by explosive gas pulsation will lift an object vertically in the cavitation region. Extrapolations of the bulk cavitation zone calculated from selected charge size and attack geometry indicated that the midget submarine was within the cavitation region causing the submarine to be launched upward by the explosion. As the submarine broached near the surface and headed into the oncoming waves caused by the concussion. Water crashed into the propeller disk, forming three distinct rooster-tail sprays syn- chronous with each passing wave. The third smallest rooster tail had dissipated somewhat by the time the photo was taken. This underwater explosion analysis has substantiated the action the midget took and strengthened photo- imagery evidence of the existence of a (Continued on page 83) elapsed time intervals were computed to be 174 seconds (approximately three minutes) after the HELENA was hit. This substantiated that the combat photo was taken at approximately 0801. (Rudimentary shadow analysis indicat- ed the time was 0801-0803). As the concussion waves approached the advancing midget, they crashed passed its conning tower onto the con- tra-rotating propellers. Generating three distinct rooster tail sprays, various pro- gressively increase in size from the ear- liest spray, the farthest and smallest. The distance between each of the roost- er tails was computed and found to coin- cide with the pattern of the propagating waves. Thus enabling to compute the distance between the observed vertical edges of the rooster tail to the midget conning tower and found to be 38 ft., match half of the midget's overall length of 80 ft. The thinner tracks were a typical char- acteristic of the Japanese Type-97 sub- marine torpedo. Test reports of U.S. conducted torpedo run trials after the war indicated only minimal wake was visible to the overhead flying observa- tion aircraft during the test runs. The thinner tracks characteristically are also indicative that they were more recent with older track defused in time. Thus their convergence in the absence of water splashes and the thinner tracks characteristic lend evidence that a sub- marine was present and fired two torpe- does at the targets. During an underwater explosion event, the chemical reaction of the solid explosive yields gaseous products and exerts high explosive pressure on the surrounding water. The disturbance (compression shock wave) near the charge propagates radially at three to five times the speed of sound. The sur- rounding water is compressed and attains an extremely high radial velocity. The compression shock wave reflecting from the free surface results in a tensile reflected wave, causing a region of April, 2000 BALLAST Seven Seas gives you the choice satellite telephone service - where you want it, when you want it. Communications. Inc. Ft. Lauderdale: 954.761.7671, 800.566.9600 Seattle: 206.633.5888, 800.250.8962 Houston: 409.271.1177 Washington, DC: 301.987.2213 Internet: www.sevenseascom.com Call 800-566-9600 ...you make the call IRIDIUM Ooeanoeii Wmose Now... Seven Seas Satellite Phones start at $1099 Plus... join our Tag Phone Dispatch Group for only $24/month INMARSAT • IRIDIUM • OCEANCELL • GLOBALSTAR A Seven Seas Circle 293 on Reader Service Card Smart Strain Gauge Level Sensor with Generic 4-20mA Output Use one sensor for all shipboard liquid levels This technology has been designed specifically for surviving the rigors of ballast tank continuous monitoring. It weighs less than 2 oz. and is con- structed from 100% pure titanium. • It's the size of your thumb • Accuracy .25% of full scale • 100% Titanium • Weighs less than 2 oz. • ABS/USCG/Uoyds approved • FM Class 1, Div. 1 Intrinsically Safe • Removal without tank entry • No mercury or other contaminants • Interfaces to your existing monitoring system • One sensor for all shipboard liquids: fuel oil, lube oil, fresh water, black water, etc. • Generic 4-20 mA output • Used in 15,000 tanks worldwide Many Options S ELECTRONIC MARINE SYSTEMS, INC. 800 Ferndale Place Rahway, NJ 07065 Use Your Technical Skills ith Mercy Snips Circle 231 on Reader Service Card • Call today for more information! 732.382.4344 732.388.5111 fax emsmarcon@aol.com e-mail http ://www.emsmarcon .com THEY COME: From Thunder Bay to Galveston, From [ Seattle to New York, they come and make a difference to the poor and needy You can Too! COME, and make your mark with us! FMTA96 Join the crew for 2 nonths. ir> lay: Mercy Ships EO. Box 2020 Garden 75771-2020 Ph. (908) 968-8841 903 met www.mercy8hlps.org Thwart; info@mercyship8.org Mercy Ships, Circle 271 on Reader Service Card
