FORE & AFT MARINE
SOUND PROOFING
| NOISE CONTROL ON BOARD | ||||
| Many a yacht skipper and his
crew have to endure a level of noise and vibration which would be
totally unacceptable elsewhere. Yet a noise level of 65 to 70 dB is
easily achieved by the use of proper sound deadening materials. As a
comparison; the noise level of an idling petrol engine equals 70 dB.
Unwanted noises are either structure borne sounds or air transmission
sounds. On board ships, the engine(s) and the propeller(s) are the
prime sources of unwanted noise. The air transmission noises of a
marine engine are chiefly related to the number of revolutions. The
more an engine is "revved-up", the higher the noise level.
These noises may be reduced effectively by application of the
sound-deadening plates, model SDP to the engine room walls and
ceiling. The special construction of these plates, with two layers of
foam and a heavy slab in between (contains no lead), provides very
good insulation from vibration as well as excellent noise absorption. VETUS SOUND DEADENING PLATE, TYPE SDP Fulfils the requirements if the ISO 4589 standard. |
The sound insulation plates
type MISO have a much simpler construction than the SDP type. MISO-plates
only provide noise absorption. The vibrations of the ship's engine are
transmitted to the vessel, through the engine bed. This specific noise
belongs to the category of "structually borne sounds".
Effective countermeasures against such vibrations are the installation
of correct flexible engine mountings and - first and foremost - the
flexible connection of the various metal pipes of the engine. It is
indeed of little use to provide a well-insulated engine installation
if no attention is paid to the noise, produced by the ship's
propeller. Cavitation transmitted to the bottom of the boat through
the water may cause appreciable reverberation, resulting in an
additional amount of unwanted noise. This specific variety of
"noise" may be eliminated in an excellent way by application
of the VETUS "Anti-Reverberation-Material", type ARM. This
material comes as a compound and is to be applied to the inside of the
ship's bottom, where the propeller is located. VETUS SOUND INSULATING PLATES, TYPE MISO Fulfils the requirements of the ISO 4589 standard. |
|||
 |
 |
|||
|
Dimensions of plates: SDP 14 x 10: Perforated vinyl
top layer, 54 21/64" x 39 3/8" x 1 27/64" VETUS SDP plates both absorb the noise and insulate
the vibrations. The structure of this plate is formed by two
polyurethane foam layers, one of 13/64" and the other of 1"
thickness. Between those two layer, an anti-reverberation slab of
5/32" thickness is located. The two layers of foam result in
noise absorption, whereas the anti-reverberation plate eliminates
vibrations. Without this type of construction, it would be impossible
to achieve the optimum sound insulation. |
This material provides sound absorption but does not
eliminate vibrations. The reverse side of the plate is sef-adhesive.
The material consists of a flexible, closed cell top layer (no oil
absorption). Insulating plates with a so-called "egg-box"
profile have definitely no better sound-deadedning capacities than
these flat MISO-plates. |
|||
Insulation detail of a boat hull and deckhead A: VETUS sound-deadening plate type SDP 1: 5/16" perforated vinyl top layer 2: polyurethane foam layer, 1" thickness 3: anti-reverberation slap, 5/32" thickness 4: polyurethane foam layer, 13/64" thickness |
 |
|||
 |
||||
| Insulation detail of the bilge | Insulation detail of a partition | |||
|
||||
