When vibrations create operational risk – not clear answers
32-channel vibration measurements in real operating conditions
Recurring vibration issues represent a real operational risk.
This case study shows how multichannel vibration measurements supported the superintendent’s decision-making process and led to a permanent resolution of the problem – without unnecessary component replacements.
The challenge and the objective
The vessel experienced recurring vibration issues which persisted despite previous service actions.
The key challenge was not the vibration levels themselves, but the lack of reliable data needed to assess real operational risk and make informed technical decisions.
The objective of the measurement campaign was to understand vibration behaviour across the entire propulsion system and ship structure, and to provide objective, decision-grade data for the superintendent.
Measurement scope and methodology
Measurements were performed during sea trials under varying engine speeds and load conditions, with 32 vibration channels recorded simultaneously.
The scope included:
- auxiliary engines Himsen 5H21/32 with generators,
- main engine Hyundai-MAN B&W 6G70ME,
- main engine foundation and bracing,
- shaft line components,
- selected areas of the ship’s structure.
Vibrations were measured in three directions (V / H / A), and the results were evaluated with reference to ISO 10816-6, ISO 20283-4, and applicable classification society guidelines.
Example of a vibration sensor mounted on the main engine foot to measure vibration levels in the vertical direction during a multichannel vibration measurement campaign.
What the data revealed
The analysis showed that vibration levels changed with the operating conditions of the propulsion system, and that similar frequency characteristics appeared in different areas of the vessel.
Not every location with elevated vibration levels was the actual source of the problem.
The behaviour of the Hyundai-MAN B&W 6G70ME main engine and the structural response of the vessel demonstrated that the observed vibrations were not random, but were closely related to the operating conditions of the propulsion system.
Measurements on the shaft line showed stable behaviour across the entire operating range, providing an important reference point for evaluating the overall system response.
Conclusions and operational outcome
- Vibration issues must be analysed at the system level, not on individual machines in isolation.
- Conclusions based on sea trial data proved critical for making the right technical decisions.
- Multichannel vibration measurements significantly reduced the uncertainty associated with point-based diagnostics.
- Following the implementation of actions derived from the measurement analysis, vibration levels stabilised and previous operational issues ceased to recur.
- The problem was permanently resolved, without costly and unjustified component replacements.
Call to action
Facing a similar vibration issue?
Before making a costly decision, it is worth measuring and understanding the behaviour of the entire system.