Changes

= Acoustical Isolation =

Acoustical isolation is extremely important in a live-aboard boat to keep noise within a comfortable range. We experience sound in terms of a frequency range measured in Hertz (Hz) and air pressure measured in decibels (dB). The ear has a very wide non-linear response to the intensity of sound, so each 10 dB increase is ten times louder. Thus a 20 dB increase is 100 times more intense. Duration is also important. Constant noise over 85 dB will damage hearing.

For reference, the ambient noise level in most homes is 30-35 dB. Car interiors are around 40 dB. A normal conversation is around 60 dB. A diesel engine room is around 125 dB (wear ear protectors!}. A jet plane taking off is around 140 dB. For bedrooms, the [http://www.who.int/ World Health Organization] recommends 30 dB with no single noise event exceeding 45 dB.

A good strategy is to eliminate sound at its source, especially in the engine room. This reduces the cost of acoustical insulation elsewhere. Noise attenuation of 100 dB is feasible. Some areas for consideration are: