Process Analysis Via Accuracy Control

Prepared in cooperation with Todd Shipyards Corporation, Seattle, WA.

Accuracy impacts on productivity. Thus, accuracy is a prime and continuing concern among professional shipbuilding engineers. They regard Accuracy Control (A/c.), i.e., abilities to regulate accuracy, fust and foremost as a management tool for continuously improving productivity. Statistics is the branch of mathematics dealing with collection, analysis, interpretation and presentation of masses of numerical data. The methods of statistics are methods of applied mathematics. Shipbuilding engineers who manage A/C programs must at least understand college-level elementary statistics. Other prerequisites pertain to the data needed. An A/C data base is a major investment. At first it requires systematic recording of thousands of measurements. Such efforts are expensive. They will deter traditional managers having shortterm goals. These people are more likely to apply what they believe to be A/C as sporadic and unsophisticated preventive steps in response to one particular customer's requirement for a specific degree of accuracy. Lack of long-term application negates the central importance of statistically-valid data which describes a shipyard s normal accuracy performances. Such data is the basis for continuing the collection of measurements by mathematically determined sampling and for continued analysis and interpretation. Competitive shipbuilders regard their A/C data base as a capital investment and means of production every bit as indispensable as a crane or a building dock. The significant cost for starting an A/C program makes sense only when it is amortized over future projects just as any other large capital investment. Costs for continuing the collection of data as a normal part of a production process, are nominal because of the sampling techniques employed.