Originally Posted by RatickleHere is most of SAE J2500 testing procedures. It actually doesn't say transom, it says vertical projection. Does the NY law say SAE J2500 or 1 meter/1 meter? There is a huge difference when in court or testing under a strict set of rules set up by SAE Engineers.
Excerpt from SAE J2500
(copied and pasted from pdf)
4.1 Measurement Site—A suitable site is a body of water free of large obstructions or reflective surfaces such as
buildings, boats other than those involved in this procedure, large embankments or breakwaters, etc. for a
minimum distance of 8 m (25 ft) from the boat being measured. The boat being tested shall either be moored
to a dock or lashed to another boat. If moored to a dock, the dock shall be of open construction so that it
presents a minimum of reflecting surfaces. If the measurement is made in open water, the boat being
evaluated shall be lashed to the measurement boat to prevent relative motion and to allow positioning of the
microphone in the prescribed location. The measurement boat shall be positioned to minimize reflected
4.2 Boat Operation—The engine shall be operated at low idle speed within the engine manufacturer's
recommended operating range, in neutral gear if so equipped. For motorboats without a neutral gear, the
engine shall be operated at its lowest operational speed. The engine shall be operated for a sufficient amount
of time to allow water to flow through the exhaust system before taking measurements.
4.3.1 The microphone shall be placed at a distance of 1.2 to 1.5 m (4 to 5 ft) above the water and no closer than
1m (3.3 ft) from the vertical projection of any part of the boat in the area adjacent to the exhaust outlet(s).
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 to minimize sound
4.3.4 The applicable reading shall be the average sound level measured during a period when the background
sound level is at least 10 dB lower than the measured sound level. Background sound level includes wind effects, noise from boats other than the one being measured, wave action, boat wakes, and other extraneous
Peak readings of intermittent sound levels created by wave slaps or changes in sound level due to
wave action and/or engine speed variation shall not be included in the applicable reading.
4.3.5 The observer shall record the applicable reading and the background sound levels taken immediately before
and immediately after the applicable reading.
5. General Requirements
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, while the word "should" is to
be understood as advisory.
PREPARED BY THE SAE MARINE SOUND LEVEL SUBCOMMITTEE OF THE SAE MARINE TECHNICAL COMMITTEE AND THE SAE SPECIALIZED VEHICLE AND EQUIPMENT SOUND LEVEL COMMITTEE
Seems to me if you took pictures or video of the LEO conducting one of these tests you'd be able to find enough mistakes to beat the ticket in court. I don't see how they can accurately perform the test with so many procedures and variables.