As the computer aided ship design (CASD) is a way to translate the owner requirements into a feasible project through a methodical treatment of ship design problems oftenly by using spirals, the computer aided ship design economics is a way to help the shipowner himself to optimize his requirements by putting the answers of the questions freauently arise to him before putting his order. From the main economical factors which are concerned by the shipowner the design speed, the economical life, and the maximum permissible price of the proposed ship. This paper gives an approach to the optimum predictions of the above-mentioned factors and attempts an analysing procedure for determining the economical particulars for a newly ordered ship. A closed design model (CDM) is developed which-besides the decisions for speed,life,and price-makes the necessary analyses to investigate the sensitivity of these factors to each other and to other technical and economical factors. The algorithm of procedure is explained, flow charts of computer programs are given, and the results of analyses are presented and discussed through the paper.