ECONOMIC CONSTRAINTS ON THE DESIGN OF AN 

 EXPENDABLE INSTRUMENT SYSTEM 



by 



W. V. A. Clark, Jr. 

 Francis Associates, Inc. , Marion, Massachusetts 



The purpose of this paper is to explain a few of the economic 

 constraints which have influenced the development of an expendable 

 oceanographic instrument. Economics control almost any engineering 

 development; an expendable device causes the cost per unit to be multi- 

 plied by large numbers and therefore is an interesting problem. 



The particular instrument involved in this development is an 

 expendable electronic BT developed by Francis Associates, Inc. The 

 device in its final form consists of a weighted thermistor probe which falls 

 freely through the water paying out wire from a spool contained in a tear- 

 drop shaped after-body. Wire is also payed out from a shipboard spool so 

 that no strains are placed on the wire link between the probe and the ship. 

 The device weighs about 2 pounds, is useful up to I, 500 feet, may be 

 deployed at ship speeds up to 30 knots, and in its present form has an 

 accuracy plus or minus . 2°C. and a depth accuracy of plus or minus 2% 

 or 15 feet, whichever is greater. 



The first exercise in this development was that of determining the 

 nature of the demand curve, that is, the amounts likely to be used at 

 varying prices. Indeed it was an early assumption that expendable BT's 

 might be procured in large volume which led Francis Associates to initiate 

 the development. The exploration of a demand curve is an old and, I must 

 confess, a disorderly process. Depending upon the industry we are in, it 

 is called economic analysis, merchandising, market research, or perhaps 

 just hustling. In its best form it consists of analyzing a market before 

 entering it, so that various levels of pricing can be traced through to their 

 ultimate effects. Perhaps the application of orderly demand curve explor- 

 ation which touches our lives most closely is that of large merchandising 

 establishments such as Sears Roebuck. In the olden days manufacturers 

 would present products to buyers; buyers, from these available products, 



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