Dockrocker here is SAE J1970
J1970
ISSUED
DEC91
1991-12 Issued
400 Commonwealth Drive, Warrendale, PA 15096-0001
SURFACE
VEHICLE
RECOMMENDED
PRACTICE
Submitted for recognition as an American National Standard
SHORELINE SOUND LEVEL MEASUREMENT PROCEDURE
Foreword—This Document has not changed other than to put it into the new SAE Technical Standards Board
Format.
1. Scope—This SAE Recommended Practice establishes the procedure for measuring the sound level of
pleasure motorboats at a position on the shore under conditions other than stationary mode operation. It is
intended as a guide toward standard practice and is subject to change to keep pace with experience and
technical advances.
1.1 Purpose—This document specifies guidelines for sound level measurements made from the shoreline of
recreational boating areas and is intended for pleasure motorboats only.
References 2.
2.1 Applicable Publications—The following publications form a part of the specification to the extent specified
herein. Unless otherwise indicated the latest revision of SAE publications shall apply.
2.1.1 ANSI PUBLICATIONS—Available from ANSI, 11 West 42nd Street, New York, NY 10036-8002.
ANSI S1.4-1983 and S1.4A-1985—Specifications for Sound Level Meters
2.2 Related Publications—The following publications are provided for information purposes only and are not a
required part of this document.
2.2.1 SAE PUBLICATIONS—Available from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001.
SAE J34—Exterior Sound Level Measurement Procedure for Pleasure Motorboats
SAE J2005—Stationary Sound Level Measurement Procedure for Pleasure Motorboats
2.2.2 ANSI PUBLICATIONS—Available from ANSI, 11 West 42nd Street, New York, NY 10036-8002.
ANSI S1.1-1960(1976)—Acoustical Terminology
ANSI S1.13-1971(R1986)—Methods for the Measurement of Sound Pressure Levels
SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely
voluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefrom, is the sole responsibility of the user.”
SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions.
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Copyright 1991 Society of Automotive Engineers, Inc.
All rights reserved.
SAE J1970 Issued DEC91
Instrumentation—The following instrumentation shall be used for the measurement required. 3.
3.1 A sound level meter which meets ANSI Standard S1.4-1983 Type 1 or Type 2 specification for Sound Level
Meters.
3.2 A microphone windscreen that does not affect the overall reading by more than ± 0.5 dB(A).
3.3 A sound level calibrator.
Procedure 4.
4.1 Measurement Site—A suitable site is the shore of a body of water or dock projecting out from the shore into
the body of water, or a raft or a boat moored to a dock or anchored so that the sound level meter or microphone
is not more than 6 m (20 ft) from shore. If the measurement is made from a dock, the dock shall be of open
construction so that it presents a minimum of reflecting surfaces. The area around the microphone and boat
being measured shall be free of large obstructions or reflective surfaces, such as buildings, high
embankments, sea walls, hills, large piers, or breakwaters, etc., for a minimum distance of 30 m (100 ft).
4.2 Boat Operation
4.2.1 The applicable reading does not require that the boat be at any specific distance from the shoreline or
microphone.
4.2.2 This measurement procedure shall not be used during the 30 s time period following engine start-up and/or
preceding engine shutdown.
4.3 Measurements
4.3.1 The microphone shall be placed 1.2 to 1.5 m (4 to 5 ft) above the water, and no less than 0.6 m (2 ft) above
the curve of the shore, dock, or platform. If on a dock or platform, the microphone shall be placed near or
beyond the end of the dock or platform. If the measurement is made from a boat, the microphone shall be
held at a height of not less than 0.6 m (2 ft) above the surface of the water. A suitable boat for this purpose is
of open hull construction.
4.3.2 The meter shall be set for slow response and the A-weighting network.
4.3.3 The observer reading the meter shall not be closer than arm's length from the microphone. Only one other
person may be within 15 m (50 ft) of the microphone when measuring from the dock or shoreline, and that
person shall be directly behind the observer reading the meter.
4.3.4 The applicable reading shall be the highest sound level measured during a period when the background
sound level is at least 10 dB lower than the maximum allowable sound level. Background sound level
includes wind effects, noise from boats other than the one being measured, wave action, boat wakes, and
other extraneous noises. Readings due to hull slaps which create intermittent sound levels shall be
disregarded.
4.3.5 The observer shall record the applicable reading and the background sound levels taken immediately before
and immediately after the applicable reading.
4.3.6 When sound level readings are taken from inside a boat, 3 dB shall be subtracted from the reading to better
correlate with shoreline readings.
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SAE J1970 Issued DEC91
General Requirements 5.
5.1 The measurements shall be conducted only by persons qualified by training to perform these measurements.
5.2 Proper use of all test instrumentation is essential to obtain valid measurements. Operating manuals or other
literature furnished by the instrument manufacturer should be consulted for both recommended operation of
the instrument, and precautions to be observed.
5.3 Proper acoustical calibration shall comprise the complete measurement system including extension cables,
etc. Field calibration shall be performed immediately before and after each test sequence.
5.4 A measurement shall be invalid if changes in the background sound level affect the applicable reading.
5.5 The use of the word "shall" in the procedure is to be understood to be mandatory. The use of the word "should"
is to be understood as advisory. The use of the word "may" is to be understood as permissive.
PREPARED BY THE SAE MARINE SOUND LEVEL SUBCOMMITTEE
OF THE SAE MARINE TECHNICAL COMMITTEE AND THE SAE SPECIALIZED VEHICLE
AND EQUIPMENT SOUND LEVEL COMMITTEE
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SAE J1970 Issued DEC91
APPENDIX A—
This procedure may be used for the measurement of sound emitted by pleasure motorboats in use on
waterways where sound level restrictions apply. Sound level is a function of the exhaust system, the boat hull,
the manner of boat operation, e.g., distance from shore, engine speed and trim angle, and other factors.
Background information is included in the SAE J1970 Rationale Statement.
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SAE J1970 Issued DEC91
Rationale—SAE J1970 has been developed for the specific purpose of measuring boat noise at the shoreline
of recreational boating areas. This procedure is intended for sound level measurements for all types of
pleasure motorboats. Since most complaints about boat noise originate from people situated on or near
the shores surrounding boating areas, sound level measurement at the shoreline is a key ingredient in
reducing complaints about the noise. SAE J1970 describes the necessary steps in making valid
measurements of the sound level generated by individual boats, so as to identify those boats which are
operated in such a manner to cause complaints about excessive noise.
Boat noise legislation as it is currently being enforced in more than 20 states throughout the U.S. is
based on SAE J34, Exterior Sound Level Measurement Procedure for Pleasure Motorboats. SAE J34
was originally developed by marine engineers for the purpose of evaluating the effect of engine/boat
design configurations on maximum noise, and was not intended for use as a procedure for enforcement
of boat noise legislation. It is not surprising, therefore, that SAE J34 is unsuited for enforcement
purposes. SAE J1970, on the other hand, was originated for the specific intent of providing enforcement
officials with a sound level measurement procedure by which shoreline noise levels can be accurately
measured.
Shoreline noise measurements can be performed by positioning the sound level meter on the shore at
the edge of the water, or on a dock, or from a boat which is anchored not more than 6 m (20 ft) from the
shore. Readings taken from a boat are subject to a - 3 dB correction: - 2 dB for acoustical conditions
within the boat and - 1 dB for reduced distance between the boat being measured and the microphone.
The actual sound level measurement specified by SAE J1970 is similar in many respects to SAE J34.
Because of the greater measurement distance from shore to boat in most situations, care must be
exercised in making certain that background sound levels do not influence readings. Consequently, the
background level shall be at least 10 dB lower than the maximum allowable sound level.
Since moored boats are usually located in the proximity of the shoreline, a 30 s time period is allowed the
operator in leaving from and returning to the shoreline area in which the noise limit will not be enforced.
The objective in providing the operator this time interval is to allow adequate time to leave from and
return to the mooring without being cited for noisy operation because of the short distance from shore.
Operators who generate noise complaints while in the vicinity of the mooring may likely be cited for
excessive exhaust noise which can be determined by applying the Stationary Sound Level Measurement
Procedure, SAE J2005.
Allowable sound level limits in residential neighborhoods have been addressed by past research done by
the United States Environmental Protection Agency and various European governmental agencies. This
research suggests that maximum rms levels of 75 dB(A) are acceptable in residential areas such as
those found on lake shores. Sound level surveys conducted by the SAE Marine Sound Level
Subcommittee indicate that a maximum (rms level) of 75 dB(A) provides an adequate margin above the
typical ambient so as to establish confidence in the measured level. Accordingly, it is recommended that
75 dB(A) shoreline limits be established in residential neighborhoods adjoining recreational boating
waters.
The SAE J1970 measurement procedure provides enforcement personnel with the means to identify
those boats/operators which generate noise complaints. Realization on the part of the operator that it is
his individual responsibility to control and maintain the noise at the shoreline is an important step in the
control of recreational boat noise.
Relationship of SAE Standard to ISO Standard—Not applicable.
Application—This SAE Recommended Practice establishes the procedure for measuring the sound level of
pleasure motorboats at a position on the shore under conditions other than stationary mode operation. It
is intended as a guide toward standard practice and is subject to change to keep pace with experience
and technical advances.
SAE J1970 Issued DEC91
Reference Section
SAE J34—Exterior Sound Level Measurement Procedure for Pleasure Motorboats
SAE J2005—Stationary Sound Level Measurement Procedure for Pleasure Motorboats
ANSI S1.1-1960(1976)—Acoustical Terminology
ANSI S1.13-1971(R1986)—Methods for the Measurement of Sound Pressure Levels
ANSI S1.4-1983 and S1.4A-1985—Specifications for Sound Level Meters
Developed by the SAE Marine Sound Level Subcommittee
Sponsored by the SAE Marine Technical Committee and the SAE Specialized Vehicle and Equipment
Sound Level Committee
Charter Member
or i could just fill the bilge with water until the exhaust go under the water 
Platinum Member
