February 2021 Airboat Demonstration

On February 8th, 2020 three airboats made runs in the Harraseeket River and noise levels were measured at pre-specified sites on the shorefront. The maps below, provided by Maine DIFW, show the GPS routes and calibrated noise measurements at each site. Two of three boats would have been in full compliance at all times with a 75 dbA shoreline limit, supporting the notion that such a limit is readily achievable in routine operation.

The following graph was constructed by one of our members from the IFW data and shows the relationship between distance and noise levels. The results from this demonstration are consistent with theoretical attenuation of 5-6 dbA per doubling of distance. It also clearly shows how boats 1 and 3 were in compliance with a 75 dbA shoreline limit throughout the demonstration.