1115. Marginal Cost Factors for Surface Combatant Ships

Paper

Abstract

The concept of utilizing marginal cost factors to determine the overall ship impact of design features is examined. The assumption is made that the design parameters for a feature such as the addition of a piece of equipment can be broken down into requirements for weight, space, manning and electrical paper and that these requirements are linearly superimposeable.
Marginal weight factors in terms of changes in ship displacement were generated utilizing a computerized ship synthesis model. The sensitivity of these marginal weight factors to variations in the size of the ship (3000 to 12,000 tons) and the magnitude of the design parameter variation was investigated. It was determined that the marginal weight variation were more a function of the ship geometry than ship displacement. Marginal weight factors varied significantly between volume and freeboard limited ships.
The validity of utilizing marginal weight factors to predict the overall weight impact on a ship is confirmed through a comparison with weight impact predicted directly by the synthesis model. The two methods were found to agree within + or – seven percent for armament systems. However, the marginal weight factored generated in this study provided a low prediction for electronic systems.
The overall conclusion to the study was that the concept of marginal cost factors is valid for predicting the impact of design changes on naval ships. However, a considerable amount of work remains before the technique can be universally implemented through the design community.