Condition Monitoring & Vibration Analysis Increases Efficiency and Performance of Yacht Propellers

In today's demanding yachting industry, the expectations placed on propellers for optimal efficiency and performance are higher than ever. To meet these expectations, condition monitoring and vibration analysis have come to the forefront of modern solutions for improving the performance and longevity of yacht propellers. Condition monitoring and vibration analysis can help increase the yacht’s efficiency and prolong its propeller’s performance, allowing for longer and smoother trips.

To maximize a yacht propeller’s longevity and efficiency, there are certain routine maintenance checks that crew can perform, such as monitoring fuel consumption, cleaning the propeller thoroughly of all marine growth, and lubricating the propeller blades with a water-repellent lubricant such as CRC 6-56. It is also important to visually inspect the propeller on a consistent basis for potential signs of damage or wear – this can be performed by crew personnel, or by a third-party diving company. Some tasks are more specialized and require specialist labor and equipment – These include vibration analysis and shaft torque surveys. When conducted correctly, these checks and surveys can result in better fuel efficiency, faster top speeds, and ultimately, a safe return home.

Vibration analysis plays an important role in increasing the performance of yacht propellers. By performing annual vibration analysis surveys, we are able to trend overall operating conditions, up to and including, propeller performance. Potential issues that can reduce performance/efficiency, and can be identified by vibration analysis, include bent shafts, propeller blade damage, and improper fitting of the propeller onto the shaft to name a few. All of these potential issues can have a detrimental effect on the vessel’s propulsion system and fuel efficiency. Identifying the root cause of vibration allows the proper corrective actions to be performed, such as reconditioning and balancing propellers, straightening shafts, performing alignments, etc.

Shaft torque analysis is more rare, but no less important. By measuring the torque being applied to each propeller shaft by their respective engines/propellers, we are able to determine if the propellers are pitched properly to maximize engine horsepower. This reduces unnecessary loading on the engines and thereby maximizes fuel efficiency. This survey is typically performed during the initial builder’s trials; however, it has become a powerful diagnostic tool when yachts are suffering issues that cannot be identified by standard inspections.

AME was called out to diagnose a yacht that was having torsional coupling failures between the engine and transmission. We performed shaft torque analysis, torsional vibration analysis, multi-channel vibration analysis, and standard route-based vibration analysis all in one sea trial. We discovered that the propeller blades had too much pitch in them, which was putting an unnecessary load on the engine. We also saw signs of misalignment which, in combination with the over-pitched propellers, were causing the couplings to absorb more torque than what they were rated for, and consequently fail.

Condition monitoring and maintenance of yacht propellers provide an invaluable tool for optimization. By using shaft torque and vibration analysis, we can monitor and analyze the specific frequencies that indicate a system’s defects or weaknesses, enabling preventive action to be taken before a critical failure can occur. This helps to minimize downtime and maximize the yacht propeller’s life, avoiding costly repairs or replacements.