For the sake of convenience, the different 

 types of submersible instruments are sepa- 

 rated into three categories: Surveying, re- 

 search and engineering. The three are not 

 mutually exclusive and there is much over- 

 lap of tasks and tools. 



SURVEY INSTRUMENTS 



An oceanographic survey may be defined 

 as a mission to determine the spatial and/or 

 temporal variations in one or more environ- 

 mental parameters. It may also include col- 

 lection of samples. Surveys generally estab- 

 lish what, where, how many and what size. 

 Research, on the other hand, answers "why." 

 Engineering missions encompass such tasks 

 as the inspection, repair or salvage of a piece 

 of hardware or other artifact. Inspection of 

 cables, pipelines or recovery of equipment 

 are examples of an engineering mission. The 

 overlapping of instrumentation can easily be 

 seen from the fact that, at one time or an- 

 other, all of these tasks may require the use 

 of tape recorders, cameras, manipulators or 

 samplers. From 1965 through 1970 the U.S. 

 Naval Oceanographic Office conducted sur- 

 veying operations with several different sub- 

 mersibles to provide design and performance 

 specifications and operational techniques for 

 oceanographic surveying instruments. The 

 primary emphasis of this project was toward 

 military oceanographic surveys, the goals of 

 which are sometimes at variance with aca- 

 demic or commercial surveys, but the tech- 

 niques and instruments used are similar. 

 Because this was the only major effort to 

 test and evaluate the use of the manned 

 submersible and contemporary equipment in 

 undersea surveying, the results of this work 

 are taken to represent current instrument 

 capabilities. 



Initially, the Oceanographic Office started 

 with the small PC-3B; thence to the larger 

 ALVIN; STAR III, DEEPSTAR 4000; ALU- 

 MINAUT and finally, BEN FRANKLIN. By 

 the time of the Gulfstream Drift (July 1969), 

 the project had resulted in the design and 

 assembly of an on-board instrument survey- 

 ing capability equal to that of a 280-foot 

 survey ship of the AGS class. The BEN 

 FRANKLIN instrument suite during the 

 Gulfstream Drift (7) is used as the prototype 



description of a manned submersible survey 

 instrument capability. Full details of these 

 instruments are contained in refei-ence (8). 

 Table 11.2 presents the weight and dimen- 

 sional characteristics. 



Water Column 



The attempt to establish the what, where 

 and how of many oceanographic surveys 

 commences at the outset of a dive. Although 

 the survey may be geological in scope, the 

 descent to the bottom is not spent leisurely, 

 because journeys through hydrospace may, 

 at any time, provide some unusual observa- 

 tions through the viewport. A suite of water 

 sensing instruments was developed to supply 

 complementary data for observations and to 

 augment the basic store of oceanographic 

 data. 



a. Water Sensor Pod: (Figs. 11.3 & 11.4) 

 Operation: The salinity, temperature, 



sound velocity, and depth sensors are in an 

 underwater housing functioning continu- 

 ously and are scanned sequentially by a re- 

 corder. A fifth data word is generated by a 

 logic element which is the sequential time 

 word. Eleven other data channels are availa- 

 ble for auxiliary inputs into the recorder. All 

 16 data channels are scanned by the tape 

 recorder every 2 seconds. Any of the four 

 parameters measured by the WASP sensors 

 may be monitored on a Nixie display. 

 Data: (Bisset-Berman Model) 



Salinity 30 to 40 ppt ±0.04 ppt 



Temperature -2° to +35° C ±0.03°C 



Sound Velocity 1.4 to 1.6 km/sec ±0.14 m/sec 



Depth 0-6100 m ±0.25% (full scale) 



Time 6-24 hr ±0.01% (full scale) 



b. Dissolved Oxygen: (Fig. 11.5) 

 Operation: The sensor is a polaro- 



graphic electrode. An oxygen permeable 

 membrane covers the sensor head. Oxygen 

 diffusing through the membrane generates a 

 small electric current. The sensor responds 

 to oxygen partial pressure, but use of tem- 

 perature-compensating circuitry allows cali- 

 bration in parts per million of dissolved oxy- 

 gen by weight. 



Data: (Beckman: Minos DOM PN 

 148250) Sensor output is converted to fre- 

 quency in a format compatible with the re- 

 cording unit of the water sensor pod or other 

 recording and display units. 



544 



