1. A method of evaluating impact of engine choice during the computer assisted design of waterborne vessels, the method comprising the steps of: defining a plurality of generic equations representative of engine specific fuel consumption as a function of at least one engine performance parameter, each of said plurality of generic equations having associated therewith an equation indicator; providing an engine library containing therein a plurality of engine specifications, each of said plurality of engine specifications defining an engine in terms of a plurality of geometric and performance parameters, said performance parameters including said at least one engine performance parameter and one of said equation indicators; selecting an engine from said engine library, said selecting having associated therewith a predetermined engine application; retrieving said engine specification associated with said selected engine from said engine library; storing said retrieved engine specification in an engine model; retrieving one of said plurality of generic equations based on said equation indicator stored in said engine model; and evaluating an engine performance simulation at predetermined operating conditions of the waterborne vessel, said evaluating being performed in accordance with said retrieved equation and said plurality of geometric and performance parameters stored in said engine model, wherein said evaluation provides geometric and performance characteristics required for designing propulsion and ship service power producing machinery for the waterborne vessel.