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Sound Level Comparisons
Personal Watercraft vs. Open Exhaust Boat - Passby Sound Level Measurement for Various Types of Boats
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Personal Watercraft
One PWC operating 50 feet from an on-shore
observer is heard at 71 dBA, a level below the recommended
75 dBA of SAE J1970*** and the Environmental Protection
Agency. In fact, two PWC operating at 50 feet from shore
are heard at 74 dBA, still below that recommended level.
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Open Exhaust Boat
In contrast, an open exhaust boat operating
50 feet from an on-shore observer is heard at 107 dBA.
(As a comparison, the dance area at a loud rock &
roll concert is between 100-110 dBA.) |
| * dBA: This is a measurement
of sound approximating the sensitivity of the human
ear. It is used to note the intensity or annoyance level
of sounds.
** "Information on Levels of Environmental
Noise Requisite to Protect Public Health and Welfare
With an Adequate Margin of Safety." EPA 550/9-74-004,
U.S. EPA, Washington, D.C. 1974
*** SAE J1970: Shoreline Sound Level
Measurement Procedure. This procedure was developed
by the Society of Automotive Engineers for the specific
purpose of measuring boat noise at the shoreline of
recreational boating areas. |
Two PWC operating 50 feet from an observer on shore are actually
quieter than
1 open exhaust speed boat operating at over one half mile
from the shore.
Four PWC operating 50 feet from an observer on shore are only
77 dBA and are actually quieter than one open exhaust power
boat operating 1,600 feet from the on-shore observer. The
fact is, it would take up to 16 PWC operating at 50 feet from
shore (83 dBA) to equal the intensity of sound emitted from
one open exhaust boat at 1,600 feet (82 dBA).
Passby Sound Level Measurement for Various Types of Boats
Results of sound level measurements performed for the New
Jersey State Police. Personal Watercraft were among the quietest
boats measured in this test. Sound was measured as "dBA",
which approximates the sensitivity of the human ear and is
used to note the intensity or annoyance levels of sound.
| Type of Boat |
Passby Level
decibels* |
Classic Inboard -
1930 Wooden Boat, Inboard Motor, Exhaust Outlet Above
the Water Line |
72 |
Single Outboard Engine -
Police Patrol Boat with single 175 Horse Power (hp), Outboard
Motor |
81 |
| Twin Outboard Engine Police Patrol Boat
with Two 155 hp, Outboard Motors |
82 |
| Personal Watercraft No. 1 -
750 cubic centimeter engine |
81 |
| Personal Watercraft No. 2 - 900 cubic centimeter
Engine, 100 hp, High Performance Model |
76 |
Inboard/Outboard with Exhaust Below Water
Line -
350 cubic inch (ci) Engine with Outboard Drive |
85 |
Inboard/Outboard with Exhaust Above Water
Line -
352 ci Engine with Outboard Drive |
90 |
| Racing Boat No. 1 - Runabout, 283 ci Engine
Exhaust Below Water Line |
105 |
| Racing Boat No. 2 - Hydroplane, 305 ci Engine |
109 |
| * A-Scale Sound level (dBA)
measurements at a distance of 50 feet. A-Scale approximates
the sensitivity of the human ear and is used to note the
intensity or annoyance level of sounds. Data from NUI
Report No. 8077.1, New Jersey State Police-Marine Division.
Nov. 1, 1995. |
See the full study conducted for the New Jersey State Police
by Noise Unlimited, Inc.
Boat
Noise Tests Using Static and Full-Throttle Measurement Methods
(1995).
Please keep in mind that this test was conducted in 1995,
and personal watercraft manufacturers have achieved a 70%
reduction in sound levels since 1998.
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