logically designed device will work. Somewhere between these two 

 points of view lies the practical answer. The important thing to 

 rennember is that there are well established physical principles, 

 and there are good materials and components, which, if properly 

 used, will permit simple instrument cases to be tight, strong, and 

 economiical. In fact, oceanographer s are as apt to have trouble 

 with low pressures and shallow-water equipment as with deep 

 equipment in deep water. With shallow-water equipment they may 

 get sloppy in design; deep cases are rugged and their design is 

 usually based on fundamentally sound principles. Pressure 

 compensation techniques often solve high pressure problems ex- 

 actly as easily as they solve low pressure problems. There are 

 reasonable descriptions of these techniques scattered through 

 the literature. 



Most of the instruments that are good for small submarines 

 miight work equally well if miounted on deep fish towed by a sur- 

 face craft. If an instrument is well designed, the chances are 

 it will work at great depths as well as at shallow depths. A 

 very practical point for you mianufacturer s to remember is that 

 the more universal you can make your instruments, the more 

 potential buyers you will have for any one model. The balance 

 between a miulti-purpose instrument and a simpler, single-pur- 

 pose instrument is an imiportant one, both to the user and the 

 manufacturer . 



With respect to the desirable recording equipment on a smiall 

 submarine, there should definitely be provision for instantaneous 

 viewing of data and there should also be provision for recording 

 it for further analysis at a later date. It would appear that six 

 to eight recording channels should be available for routine nneas- 

 urements such as temperature, salinity, and depths, and a few 

 more of the recording channels should be reserved for recording 

 variables of particular interest to a particular dive or program. 



It is likely that a deep research vessel would be used much 

 like other research ships. As such, a biologist might use it for 

 three or four trips on his problems and then when his work is 

 finished, or his instruments quit, or his time runs out, he would 

 turn the submarine over to a geologist or someone else with a 

 new set of equipment and interests. 



A research submarine looking for biological specimiens or 



169 



