Shipbuilding Industry

Safety and comfort on ships are highly influenced by noise and vibration. National and international regulations limit airborne noise as well as the tolerance level for vibrations. When exceeding these limits, unrestricted operation permits will not be issued for newly built ships or for ships that have been substantially reconditioned.
Noise reduction on ships - different to stationary installations - is mainly a matter of sufficient structure-borne noise and vibration control. Neighbouring noisy and quiet rooms demand high isolation efficiency. Helical steel spring elements are able to provide the required properties. Besides good structure-borne noise control due to high load capacities and low natural frequencies, these spring isolators have other properties that are important for the safety on board:

  • Resistant to both extreme high and low ambient temperatures

  • Nonflammable,

  • Non-ageing,

  • Corrosion resistant,

  • Maintenance free,

  • Easily installed.

To get an optimal insertion loss, the design of ship foundations has to consider both, static and dynamic aspects. High impedance of a foundation also improves the insertion loss of the elastic support system.

Fig. 1 - Double Elastic Support System


High noise and vibration control is required for passenger and naval ships – although for different reasons. A double elastic support system – see Fig.1 - achieves insertion losses of more than 50 dB, as shown in test results of the Batelle Institute – see Fig. 2.

 

Fig. 2 - Test results for a double elastic support system (MWM/320kW) on a passenger boat “Brienz”

Fig. 2 - Test results for a double elastic support system (MWM/320kW) on a passenger boat “Brienz”


Typical applications are elastically supported decks, bridges, machine control rooms, hydraulic aggregates, or elastically suspended containers used as berths in motor-coasters. The installation of various equipment on a common elastically supported base frame offers additional advantages in maintenance and structure-borne noise control compared to installing single units separately.
The high temperature stability of the spring units permits elastic support of hot equipment, such as exhaust gas systems and piping, without additional measures. Naturally also prestressable elements can be used, they simplify the installation and enable the exchange of elements without the necessity to lift the complete elastically supported system.