DEEP SEA FREE INSTRUMENT PACKAGE 



by 



Philip P. Bedard 

 Narragansett Marine Laboratory, University of Rhode Island, Kingston, R.I. 



INTRODUCTION 



The buoy that will be described in this presentation was conceived as 

 a solution to the problem of obtaining oceanographic data from very near 

 the ocean bottom. The specific aim of the project is to obtain current 

 readings from the bottom of the Gulf Stream. As of this date, four current 

 meter installations, totaling 75.8 hours, have been made on the ocean floor, 

 one of these installations being in the Gulf Stream. 



THE SYSTEM 



Available Methods 



There are a number of alternatives that can be considered when one 

 desires to make measurements very near the ocean floor. One method would be 

 by the means of instruments attached to an anchor line that extends upward 

 to a surfafce buoy (Richardson, et al, 1963). In an area such as the Gulf 

 Stream, the maintaining of such a mooring can be a difficult proposition. 

 Another method is the use of a current meter suspended from a drifting ship 

 (Pratt, 1963). Current meters have been mounted on manned deep submersibles 

 (LaFond, 1962). Information regarding bottom currents has also been in- 

 ferred from photographs of bottom ripple marks (Hurley and Fink, 1963). 



Ftfee Falling Buoy 



Our instrument package uses a method described by Isaacs and Schick 

 (1960), where a free falling vehicle falls to the bottom and spends a de- 

 sired amount of time there collecting and storing data. At the end of this 

 time the ballast holding the instrument package on the ocean floor is re- 

 leased, and the package rises to the surface under the force of its self- 

 contained flotation material. 



Instruments Used 



The oceanographic sensor selected for such an instrument package 

 must be capable of self-contained operation for the length of time over 

 which it is desirpd to make observations. Due to the limited amount of 

 flotation available in our particular configuration, equipment weight in 



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