Analisis Penyebab Kerusakan Poros Pompa Air Tawar Pendingin Mesin Induk: Studi Kasus di KN. Prajapati

Abstract

This study aims to comprehensively analyze the causes of the damage to the main engine's freshwater cooling pump shaft and formulate effective preventive solutions. This study uses a case study design with a mixed method approach that combines qualitative and quantitative methods to analyze the damage to the main engine's freshwater cooling pump shaft. The population in this study is all components of the main engine's freshwater cooling system. The research sample is focused on the main engine's freshwater cooling pump shaft that experienced damage. Data analysis was carried out in stages using the triangulation method to increase the credibility of the research findings. Visual inspection showed that all shaft samples experienced fatigue cracks that originated from the radius fillet area on the bearing seat, namely the diameter transition zone that becomes a stress concentration. The crack pattern is in the form of semi-circular beach marks which are typical for fatigue failure due to repeated cyclic loading. RCA analysis identified three main root causes: (1) Chronic misalignment between the pump and the drive motor that causes non-uniform radial loads and stress concentrations on the shaft; (2) Sub-standard shaft material quality with sub-optimal heat treatment, resulting in low fatigue strength; and (3) Cooling water contamination with acidic pH and high chloride which accelerates corrosion and material degradation. It was concluded that the failure of the KN. Prajapati main engine's freshwater cooling pump shaft was caused by a combination of three interacting root cause factors, namely chronic misalignment between the pump shaft and the drive motor, sub-standard shaft material quality, and cooling water contamination and a high chloride content of 185 PPM which created a corrosive environment.