Noise and vibration, our business for your comfort on board

With more than 50 years of experience, Intersona BV is the noise and vibration consultancy firm for ships worldwide. Drawing on decades of knowledge and extensive experience, our consultants provide shipyards and shipowners with practical solutions to minimise noise and vibration issues. As independent experts, we base our recommendations for noise and vibration reducing measures on physical principles and technical properties of materials. Since 2020, Intersona has been certified by Bureau Veritas to carry out noise and vibration measurements related to the COMF additional class notation (COMF NOISE and COMF VIB).

Design and engineering phase

At Intersona, we proudly support a broad spectrum of maritime projects, working on all types of vessels from the initial design phase through to active
operation. During the design phase, our consultants provide calculations, advice, and drawings related to noise and vibration.

Evaluate noise and vibration sources

Our consultants can assess all relevant noise and vibration sources, including machinery mounting. We provide recommendations to minimise noise and vibration at the source, resulting in improved comfort throughout the entire vessel.

Noise level prediction

Our experts can predict noise levels in work areas and accommodation areas using semi- empirical calculation models. Based on these predictions and the applicable noise requirements, effective noise-reducing measures can be recommended.

Natural frequency calculations

Our consultants can calculate natural frequencies using analytical models and/or FEM (modal analysis). Based on the predicted natural frequency and excitation frequencies of vibration sources, effective measures can be recommended to prevent resonance.

Design and assess insulation & floor plans

Our independent experts can design or assess various drawings such as flooring, insulation and damping plans related to noise and vibration.

Construction phase

During the construction phase, Intersona’s consultants review designs and calculations of suppliers, conduct visual inspections, and perform natural
frequency measurements.

Assessment of designs and calculations of suppliers

Designs and calculations of noise and vibration sources provided by suppliers can be assessed by our experts on behalf of our client. The aim is to verify the starting points of our noise level predictions and to consider interactions between systems.

Visual inspections

During the construction phase, our experts can carry out onboard inspections to verify whether machinery, pipework, damping materials, insulation, flooring, linings, and other components are installed correctly from a noise and vibration perspective.

Natural frequency measurements

Our experts can perform natural frequency measurements by analysing the response to an impulse excitation, commonly known as a bump test. Based on the measured natural frequencies and the excitation frequencies of vibration sources, effective countermeasures can be recommended to prevent resonance.

Commissioning & operation phase

During the commissioning phase, Intersona conducts measurements during sea trials to verify whether the ship meets the previously agreed-upon requirements. These measurements, including analysis and reporting, are carried out following the IMO and ISO requirements. In addition, if damage occurs that may be related to vibrations, Intersona’s experts can carry out measurements to help troubleshoot the issue. These troubleshooting measurements aim to identify the root cause of vibration-related damage by providing insight into the dynamic properties of the relevant systems.

Noise measurements

Noise measurements can be
performed by Intersona using a
calibrated Class 1 sound level meter, including noise spectra analysis with one-third octave bands and fast Fourier transform.

Vibration measurements

Our experts can perform vibration measurements using calibrated sensors and an analyzer, including recording
waveform and vibration spectra analysis (one-third octave bands and fast Fourier transform). We assess vibration levels related to (dis)comfort, and potential damage risks, aiming for
long-term machinery operation.

Shaft power measurements

Intersona experts can perform power measurements on shafts using strain gauges and shaft speed measurements. For propeller shafts, propeller curves can be determined. These measurement results can be used to assess ship speed and for EEDI calculations.

Remaining measurements

In addition to noise, vibration and shaft power measurements, we also perform the following measurements:
  • Torsional vibration measurements (strain gauge, laser)
  • Bollard pull measurements (load cell)
  • Whirling measurements (proximity transducer, laser)
  • Dynamic displacement measurements (laser)
  • Dynamic pressure measurements
  • Multi-channel measurements