our engineering outlays) we would end up with an acceptable cost of around 

 $20 to $25. Within this cost there would have to be what we know as "G & A" 

 and some sales costs. Although we squirm at their presence and their 

 amounts, these costs seldom run below 20 to 25%, which would point to a 

 manufacturing cost of $15 to $20. Examination of the costs of any instru- 

 ment system shows that labor costs including manufacturing overhead run 

 in the neighborhood of 50% with a range of 40 to 60%. Since our expendable 

 BT is going to have to be a simple device we shoot for 40% labor and 60% 

 material which tells us that our material will cost around $9 to $12 and our 

 labor $6 to $8. Proceeding backwards through the jungle of costing, we 

 know that labor will involve overhead. In this case, it probably will be 

 high because we know that this device will demand extensive Quality 

 Control. This would finally say that our labor cost must be in the order of 

 $3 to $4 or somewhere in the line of one manhour all the way from raw 

 materials to accepted, packed, and shipped finished products. 



We know now more and more about our design. We know that it 

 must be small, it must be brutally simple, and that we are not going to 

 dance unless our raw materials are in total around $10 with downward 

 revision possible. Since we know we are dealing with a ballast weight to 

 sink the device and a group of molded parts and electrical connections, we 

 begin to see that our budget for temperature sensor and our transmission 

 link to the ship are in total something like $6. We also know that our elec- 

 trical design should concentrate the electronics in the shipboard gear, 

 keeping the expendable sensor simple. 



We are now ready to examine the constraints which accuracy places 

 upon our economics and here we find a favorable effect. When we say the 

 word accuracy, it is important that we know what we are saying; and in 

 the case of expendable BT, our meaning is clearly the classic QC meaning: 

 lack of unintentional deviation between different units. (Under this defini- 

 tion a Chevrolet is a higher quality automobile than a Rolls Royce. ) If our 

 BT is to be as cheap as we want it to be, it will not permit skilled hand 

 operations; it will demand highly automated machined processes. Automated 

 machined processes tend to produce identical units; dispersions are typcially 

 narrow. These are the logical results of die casting, injection molding and 

 automatic screw machine, and mechanized chemical processes especially 

 continuous ones. 



A further constraint which emerged early in the design was one which 

 said that the manufacturing technologies should be processes which lent 

 themselves to thorough process control and easy acceptance testing. It is 



365 



