Soundac® NGN2000 Anti-drumming fibreglass reinforced constructions Description Soundac® NGN2000 is a special formulated blend of polymers designed to supply a final structure of fibreglass reinforced plastic, fibreglass, plastic and wood with very high damping of structure born noise. The thickness ® ratio between the Soundac NGN2000 and the subsoil is minimal 1 : 3. It should be applied at the stage where the overall structural thickness has been attained and a constraining FRP layer should added in thickness about 1/3 of the main structure thickness. Application The noise problem on a motor yacht can be divided into: Structural born: Structure borne noise radiated from the hull, bulkheads and deckhouse. This is caused by propeller cavitations and vibrations induced at the engine foundation. Airborne noise: Direct transmitted airborne noise from the engine. Sound reduction: Viscoelastic damping Soundac® NGN2000 in the part over propeller and around the engine foundation. Acoustics & NoiseReduction BV - Celsiusstraat 26 - 1704 RW - Heerhugowaard tel. +31 (0)72 57 27 390 - fax +31 (0)72 57 21 256 - e-mail [email protected] - website www.anr.nl Bankrekeningnr. 67.57.82.775 - K.V.K. nr. 37100240 - BTW nr. 8103.71.315.B.01

Stiffening of the deckhouse to avoid low frequency vibrations Before and after treatment measurements in the aft cabin of a 29’ motor yacht. Stern and boat bottom over the propeller area treated with viscoelastic sheet Soundac® NGN2000. Thickness of constraining layer is 30 % of the GRP base thickness. 110 Sound pressure level (dB) Conventional airborne sound insulation of the engine room by means of barrier mats and sound absorption materials. Sound pressure level in dB In case of installation on fibreglass hulls the surface should be grinded with a steel brush. A standard layer of poly-ester...