The proper choices of analytical methods, design specifications, machinery selection and their layout during the ship equipment design stage, are generally made of a number of possible alternatives. The problem of reaching at a final decision that is balanced in an overall perspective is extremely vital, especially when the decision is to be taken based upon multi-criteria objectives which may be mutually exclusive, and again, when there are alternate approaches to various decision making methods. In such problems, which are extremely subjective to personal likes and dislikes, and highly dependent upon conceptual variations, the fundamental nature of alternate objectives attain an amount of fuzziness, leading to discretionary difficulties. As a result of which, instances of making use of the experience and ingenuity of engineers and specialists, are common. The analytical process of this evaluation problem is broken down here into a hierarchy model, an impact model and an evaluation decision model. In order to postulate the conceptual, qualitative and fuzzy-quantitative elements, an analytical evaluation method based upon these models, is proposed through a multi-criteria analysis using the fuzzy theory. The choosing problem of liquid level measuring instruments for oil/ballast tanks, and the problem of proper selection of a comfortability index and then the evaluation of thermally comfortable room environments in accommodation spaces, are presented here as two typical applications of the proposed method.