Knowledge Base

Noise Emitted by Air Conditioning

As acceptable noise levels underway is important, it is even more important that the noise levels at anchor condition are very acceptable.

Silent Line by van Cappellen received an International Award for Designing the most quiet Yacht ever build so far achieving 26 dB (A) in the Guest cabins forward of the Engine Room while the generator set was running and AC at 50% load.

Press Voice: Showboats International

An Excellent Emissary, 12/01/2006

Aside from the yacht’s scale and execution, the greatest success may be the yacht’s sound engineering, accomplished with the assistance of Sjaak van Cappellen of Silent Line Noise and Vibration Control. Because savvy owners know it can be harder to quiet an aluminum hull than a steel one, Donovan noted that specific sound levels were part of Mirgab V’s contract. The unusual thing for a builder was » that Donovan said that with a smile. While controlling sound is a balancing act of rubber mounts and heavy insulation versus contracted draft and running speeds, reducing noise is a hot-button issue at the yard and has sparked innovations large and small.

So did Burger meet the target numbers? With characteristic Midwestern humility, Donovan replied that Mirgab’s readings were 20 to 25 decibels below contracted limits, depending on area and conditions. "With one generator running and the air conditioning on low, the reading is twenty-eight decibels in the owner’s cabin," said Donovan. "Under way, readings in the Owners cabin are in the forties."

To achieve these remarkable numbers, Donovan said the yard "floated everything, including the ceiling, utilized double glass on all port lights, enclosed the wire chases and added a thrust bearing on each drive unit." And, yes, the semi-displacement hull still delivers performance—a 16-knot cruising speed and 18.5 knots wide open.

"Without question, our number one intent was to design and build a product that would conclusively elevate the Burger brand; to at least get us on par with the northern European yards in fit, finish and performance," said Ross. "I think it is safe to say Mirgab has taken Burger to that level."

Source: www.showboats.com/Articles/Features/An-Excellent-Emissary-4.asp

In order to achieve low noise levels at anchor condition (emitted by Air Conditioning) the following is important:

  • Position of the fan Coil unit
  • Sound reducing box around the Fan Coil unit
  • Low speed at the air intake
  • Special attention to be given to the air outlet box
  • Low speed at the air out let openings
  • Sound reducing tube between the fan coil unit and the air outlet box

From experience (and measurements) we learned that the noise level emitted by fan coil units (at 1 meter from the unit) is approx. 50 – 55 dB (A). This has (and can be) reduced to noise levels lower than 30 dB (A) in Guest / VIP / Owners and Public areas. In Crew cabins (relative) small areas 30 – 35 dB (A) can be achieved and is very comfortable.

For additional information on Silent Line Products (SLP) materials check www.silentlinegroup.com