The selection of appropriate propulsion system is one of the most critical decisions in the design and development of a successful ship production environment. During such decision making process which essentially involves qualitative and quantitative multi-criteria selection, a tradeoff between tangible and intangible factors is essential to select the best amongst the equals. In this case study, the design team was tasked to select suitable propulsion system for a ship under design. The team uses analytical decision making tool, such as Analytic Hierarchy Process (AHP) in this case, to arrive at a informed decision. The team could compare many non-comparable but interlinked parameters like technical parameters, cost, time, vulnerability etc using AHP. The team could also harness the expertise of team within the arrived consensus decision. This study illustrates that the decision arrived through analytical methods tend to be accurate and practical than an intuitive decision. Keywords: Analytic Hierarchy Process (AHP), Propulsion system selection, Multi criteria decision making. I. Introduction The process of ship design begins with an amalgamation of a numerous ideas from all the stakeholders. While the ship designer plays a vital role to translate these into an engineering possibility keeping in mind the compliance to parameters like safety, environment and the role, most of the times, various requirements and characteristics conflict with each other. It is desirable, initially, to place a few rigid constraints on the design as possible. However, there can be incompatibilities because some characteristics have a variety of interdependencies with other characteristics and so only by careful analysis it is possible to determine the full implications of setting a requirement i.e. essential condition. This paper explores the variety of interactions that occur between elements of propulsion system and outlines few of the consequences of trade off. In this case study, an attempt is also made to highlight major imponderables that could arise during the design process, selection process and the possible implications of certain actions using a broadly defined model. The case of Multi Criteria Decision Making (MCDM) of 'selection of propulsion plant' is unique in nature and a suitable analytic method is required to facilitate the designer to select the best option which can meet all the Staff Requirements (SR). The Analytic Hierarchy Process (AHP) 1 is one such tool which suits this MCDM process involving several decision makers with different conflicting objectives to arrive at a consensus decision. In this case study, a design team has been tasked to select an appropriate propulsion system for a medium cargo ship of following key SR :- (a) Principal particulars: - Length Overall: 150-160m, Beam Max: 14-15m, Mean Draft: 5.0m, Standard Displacement: around 8000 Ton, Nominal Speed : 25 knots, Endurance: 5500 Nautical Miles(minimum). Helicopter capability : Capability for landing only of weight of 11 T (Max). (b) All machinery and systems selections to meet Safety of Life at Sea (SOLAS) conventions and regulations issued by International Maritime Organisation(IMO). (c) Use of 'all electrical system' (electric ship) has been ruled out due to various constraints. Ship propulsion system criteria The performance requirements of a ship during the design phase guides the type and combination of the propulsion arrangement selected. There will be certain criteria/characteristics associated with a particular propulsion system which helps refining the available choices for the associated systems and to an extent also the type of hull. The important criteria/characteristics considered for the ship under design table are:-