L^^ INTRODUCTION 



Installation of the Oceanic Telescope was completed success- 

 fully on October 9, 1968, and since 2009 hours on that date a 

 continuous record of scientific and engineering data has been 

 obtained. 



The Oceanic Telescope is a very stable array of temperature, 

 pressure, and tension sensors located on a taut, horizontal cable 

 at 700 meters depth pointing toward the deep South Atlantic on a 

 bearing 155° true from St. Davidfe Lighthouse, Bermuda. The 

 purpose of this array is to observe internal waves in the main 

 thermocline and to obtain engineering data required for the design 

 of a larger scale, longer-lived future array. The taut, horizontal 

 cable is nearly two miles long and holds three sensor stations 1000 

 meters apart. The sensor outputs are measured, digitized, and 

 stored on magnetic tape by a shore-based automatic Data Acquisi- 

 tion System connected to the array by a bottom cable. A schematic 

 drawing of the telescope is given in Fig. 1-1. Preliminary analysis 

 of the data indicates thermal fluctuations over a 2 C range and a 

 broad frequency spectrum. Pressure fluctuations indicate vertical 

 movements nominally under 1.5 meters, but occasionally as large 

 as ten meters and constant for many hours. 



Five weeks of intensive effort at Bermuda were required for 

 system assembly and test, ship loading and sea deployment. The 

 MIT group was supported in assembly, test and loading activities 

 by the shop and other facilities at Navy Operating Base, Bermuda 

 under the supervision of the ONR representative. Our vessel load- 

 ing and sea operations were supported by vessels and crew attached 

 to the Navy Sofar Station (Columbia University Geophysical Field 

 Station) and the Bermuda Biological Station. The principal vessels 

 used were the tug boat, T-426; the cable laying barge, YC-1378; 

 the R/V Panulirus; and a pontoon barge. 



The project was initiated in June 1967 with the objective to 

 attempt installation before winter. We succeeded in this effort but 

 were thwarted at the final stage of installation. On 24 November, 

 1967, when the inner mooring was within 90 fathoms of the bottom, 

 a faulty armored cable junction parted at 25% rated ultimate load. 

 The array was immediately recovered and subsequently repaired 

 by the manufacturer at no cost to the government. Project activity 

 remained at a slow pace characterized primarily by hardware testing 

 until June 1968 when the cable repairs were completed. Preparations 



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