up to 200 pounds. A radio beacon having a range of 5 to 10 miles 

 has been installed to facilitate location and recovery. The 

 tracking ajid command link is a simplified version of the three- 

 dimensional underwater range tracker, mounted on a ship. The 

 instrumentation to be used in this vehicle remains in large mea- 

 sure to be developed. Initial instrumentation includes a thermis- 

 tor probe mounted forward and a high frequency, narrow beam 

 echo sounder to pick up the details of bottom topography. Work 

 will soon begin on a recording system suitable for general appli- 

 cation and data recording consistent with the space, power, and 

 weight capabilities of the vehicle. 



Ordnance Research Laboratory, Pennsylvania State University, 

 has developed the MICROTHERMAL MEASUREMENT SYSTEM 

 which permits the measurement and recording of horizontal or 

 vertical temperature differentials as small as one thousandth 

 degree centigrade by use of thermistor probes spaced on a bar 

 which can be lowered to any desired depth down to 1, 000 feet. 



And now in the time remaining, I will describe a requirement 

 in an area which I believe is specific to the Bureau: 



UNDERWATER WEAPONS RANGES: The performance of wea- 

 pons cannot be adequately tested and evaluated in the laboratory. 

 This work has to be done on a range. For underwater weapons, 

 such as torpedoes, this must be an underwater range. The rapid 

 development since World War II of sophisticated underwater 

 weapons has called for a parallel de velopment of underwater 

 ranges to test and evaluate these weapons. Several of these ranges 

 already exist and are constantly being innproved, and others are 

 in the planning stage. One of the better known ranges is in 

 Dabob Bay and is operated by the Naval Torpedo Station, Keyport, 

 Washington. The Applied Physics Laboratory, University of 

 Washington, developed the three-dimensional acoustic underwater 

 tracking facility for this range. The range at San Clemente 

 Island, off the California coast, is described by H. R. Talkington 

 in the U. S. Naval Institute Proceedings of June 1960lZ . The ranges 

 in existence, and planned, vary in size from 1 to 10 miles wide, 

 3 to 70 miles in length, and 150 to 5, 000 feet deep. 



In order to analyze and evaluate weapon and equipment perfor- 

 naajice intelligently in an underwater range, it is necessary to know 



j/ Vol. 86. no. 6, p. 93. (ED.) 



149 



