Airboat
Airboat means a vessel that is supported by the buoyancy of its hull and powered by a propeller or fan above the waterline. This definition should not be construed to mean a hovercraft, that is supported by a fan-generated air cushion.
Source
36 CFR § 1.4
Scoping language
The following definitions shall apply to this chapter, unless modified by the definitions for a specific part or regulation: