keep sailing the yacht, pictured above, within J-class racing limits,
J&A Enterprises designed noise controls optimized for lightweight.
To reduce exhaust system noise, custom exhaust silencers were designed
and built by J&A's affiliate, Soundown. Special silencers were
developed for the engine room ducts, designed to meet fire protection
requirements and meet noise attenuation goals with a single treatment.
Then the engine room insulation was optimized for good noise reduction
with minimum space and weight, while still complying with MCA and
Lloyds safety requirements. The final construction of this Danish
built yacht, realized additional weight savings compared to design
estimates, while still meeting the objectives for quality of finish
and noise reduction. This allowed for the weight saved from the
interior to be added as ballast in the keel, further improving the
sailing performance of this beautiful yacht.
This is a 175 foot aluminum sailing yacht built by Alloy Yachts.
During sea trials, the J&A engineer was assured that the pitch
at which the propeller was operating was the design pitch. J&A
suggested that the pitch be increased which was found to be a more
optimum setting for noise mitigation. Also, J&A recommended
grinding the anti-singing edges along the entire trailing edge of
the blade to reduce noise. J&A's experience with propellers
is that an effective anti-singing edge should be executed by chamfering
the suction face of the trailing edge, not the pressure face.