EMHA investigated the repeated failure of propulsion engine components on an inland vessel. After obtaining a comprehensive recording of vibration data, analysis showed that the cause of the failures was a resonance of the exhaust piping. The natural frequency of the exhaust piping was excited by the combustion frequency of the engine, which resulted in vibration levels up to 304 mm/s RMS, versus a typical allowable level of 50 mm/s RMS.

Our engineers could improve the situation significantly by implementing the following recommendations:

• Improved exhaust piping support,
• The replacement of the exhaust elbow by a lighter alternative