Ships can navigate several months on sea. Maintenance and supply are the base for ship successful navigation and mission. Every type of equipment should have a maintenance plan. If it is a corrective maintenance plan, some risks are inherent. This study pursues a Management Maintenance System considering minimal costs, where the best equipment availability and performance is the objective. For this work, an air compressor was chosen as study case from a ship and considered three study stages. The first stage consisted of the definition of evaluation criteria and its meaningfulness. The data treatment from the first stage can provide enough information to define the second stage’s maintenance methodology decision. Also, the decision-making itself based on the process is the third stage. The development of decision-making methodology for maintenance management was based on a Fuzzy method considering a Risk-Based Maintenance on ship equipment.