Knowledge Base
Water Flow Noise
The above shown Yacht (Millennium 140’, Mulder Design) reached 67 knots. As Silent Line by van Cappellen was involved related to Noise and Vibration Control we were confronted with water flow noise (see photo above).
From experience we learned that the influence of water flow noise (flat sea condition) is in between 5 – 10 dB (A) pending on the ship speed. This means that in case the ambient noise level is 60 dB (A), caused by the main engines etc, the overall noise level will end up between 65 – 70 dB (A) due to water flow noise.
In case the hull structure is “hitting” wave tops, causing low frequency noise with a relative high level of impact, the overall noise level will even become higher.
Sound deadening treatments: (to be applied in local areas)
As weight is an extremely important factor onboard fast motor Yachts “high mass materials” can not be used. The alternative solution is lightweight sandwich sound deadening materials as shown below.
SLP – SONIC ultra LIGHT
SLP – COMP (2 COMPONENT)
For additional information on Silent Line Products (SLP) materials check www.silentlinegroup.com
Another example (mainly onboard high speed, lightweight Yachts) is noise emitted by waves against the hull (chine) at anchor condition.
In case weight is extremely important (in most of the cases onboard high speed Yachts) the same lightweight sandwich anti drumming materials. In case weight is less important a high mass rubber sheet (as shown below) can be installed above and below chine level.
SLP – MASS (Jute on one side)
For additional information on Silent Line Products (SLP) materials check www.silentlinegroup.com