Florida Sportsman Magazine
Letter to the Editor
jerry@floridasportsman.com
jeff@floridasportsman.com,
RE: Boating / Airboat article by Chris Christian
VanHorn and Christian have collaborated on articles for quite a number of publications over many years. VanHorn owned a direct drive Cadillac powered 18' Kennedy airboat for several years. It was equipped with flex pipe exhaust and mufflers. He used this boat primarily to scout shallow areas and to fish during winter low tides in the Tarpon Springs and Boca Grande areas.
A DDCadi pushing a big airboat with several adults onboard often has to operate at or near full throttle to get around. All machinery, motor vessels or motorized transportation operated at wide open throttle generates maximum sounds. Most airboats are designed to operate efficiently at half throttle or less.
Allegations that a typical airboat prop breaks the sound barrier is inaccurate. Any time an air prop RPM surpasses 3,000 RPM mark, it is exceeding any air propeller manufacturer's specifications. At propeller rotation speeds of 3,000 or more, the tip approaches the speed of sound and the prop tip creates a sound pitch that is annoying to many folks. Most airboaters keep their prop speed well below the 3,000 rate.
The assertion that a Counter Rotator gear reduction unit is required to significantly reduce airboat sounds is also inaccurate. The use of solid exhaust piping instead of flex pipe offers significant motor sound improvements. Many automotive powered airboats currently run reduction gear units that are ratioed at 2.38 / 1 or deeper, greatly reducing overall sounds by operating with a propeller that spins at notably slower rates.
Airboaters have accepted their craft need to reduce sound levels and many have attacked that challenge with vigor and American ingenuity. Members of Florida Airboat Association volunteered many hours of vessel time for the FFWCC / FAU Airboat Sounds Study and the overwhelming majority of local enthusiast organizations have supported the requirement for all airboats to be equipped with effective engine mufflers.
Hopefully, future FS articles dealing with airboats will more carefully document the steps most enthusiasts are taking to make their vessels more compatible with Florida's unharnessed growth.
Dave Markett
Tampa, FL