TOWED SEA TEMPERATURE STRUCTURE PROFILER 



E. C. LaFOND 



U. S. Navy Electronics Laboratory 

 San Diego, California 



ABSTRACT 



Vertical strings of temperature transducers 

 have been deployed by the U. S Wavy Electronics 

 Laboratory from fixed platforms buoyed from 

 floats or the sea floor and towed horizontally. 

 The technique of towing from surface ships has 

 proved most valuable in the study of internal 

 waves, fronts and other thermal structures in 

 the program to achieve vertical profiles of the 

 sea. 



The USNEL thermistor chain is a string of 3^ 

 temperature sensors that operates in essentially 

 a subsurface vertical line as the ship moves oh 

 the surface. The signals from the sensors are 

 scanned electronically and interpolated for all 

 whole degree Centigrade isotherms, which are 

 printed on a continuous chart. In addition to 

 the analog presentation of 2 dimensional tempera- 

 ture structure (depth and distance) the water 

 temperatures at the 3^ levels are planned to be 

 punched on computer tape for later machine 

 analysis. The depth of the array is monitored 

 by means of a pressure transducer at its sub- 

 merged end. The thermistor chain has been used 

 for a year and a half in the Pacific Ocean from 

 Canada to Central Mexico and as far afield as 

 Honolulu. The main difficulty experienced, now 

 eliminated, was lack of watertight integrity in 

 the underwater temperature sensors, electrical 

 harness and cable connectors. 



The advantages and disadvantages of the equip- 

 ment for oceanographic research as well as some 

 of the results are discussed. 



INTRODUCTION 



The USNEL towed sea temperature structure pro- 

 filer is essentially a string of thermal sensors 

 held suspended in a near vertical attitude in 

 the sea while the ship is moving forward. The 

 sensing elements are located at selected inter- 

 vals along the faired link chain from the sur- 

 face to a depth of 800 feet and cause associated 

 electronic recording equipment to provide iso- 

 therm profiles that are recorded wi uh reference 

 to depth and distance while the ship cruises 

 ahead . 1 



The USNEL thermistor chain thus makes feasible 

 a worldwide acquisition of data on the vertical 

 temperature structure of sea water since the ocean- 

 ographic research vessel USS MARYSVILLE (Fig. l), 

 which deploys the chain, is capable of sailing 

 anywhere in the oceans. 



The hardware, consisting of hoist and chain, 

 was designed and manufactured by the Commercial 

 Engineering Corporation of Houston, Texas. The 

 contouring temperature recorder was manufactured 

 by the Scientific Services Laboratory, Inc. of 

 Dallas, Texas, and is based on a design by 

 Dr. W. S. Richardson of the Woods Hole Oceano- 

 graphic Institution. 2 Three previous units have 

 been constructed. The thermistor beads were pro- 

 duced by S. P. Fenwal Electronics, Inc. of Framing- 

 ham, Massachusetts, from specifications by the 

 Scientific Services Laboratory, who encapsulated 

 the beads. The harness (underwater electrical 

 leads) were manufactured by Spectra Strip Wire 

 and Cable Corporation of Garden Grove, California. 



DECK AND SEA UNITS 



Oceanographic Chain Hoist 



The oceanographic chain hoist3 is a self- 

 powered winch designed for oceanographic work 

 requiring measurements to depths as great as 

 8^0 feet when the ship is underway at very slow 

 speed and to depths of approximately 5^0 feet at 

 a speed of 13 knots. The hoist that raises and 

 lowers the chain is powered by a diesel motor and 

 controlled by a hydraulic drive, all on a single 

 foundation measuring 11.5 by 18 feet. The drum 

 is 7 feet in diameter and its total height with 

 chain is 9-5 feet from the deck. The drum stores 

 900 feet of articulated chain. The 900-foot 

 chain, the drum on which it is wound and the hoist 

 weighs a total of 37>500 pounds. 



The towing device connecting the surface vessel 

 to the weight, or "fish, " is a special articulated 

 tow chain (Fig. 2) which is composed of fairly 

 flat streamlined links about a foot long. 9 inches 

 wide and 1 inch thick. 



Between the two steel fairing cheeks on each 

 link is a channel to house the electric cable 



Superior numbers refer to similarly numbered references at the end of this paper. 



53 



