Abstract: An underwater flow turbine includes a gondola having an interior, a generator in the gondola interior, a rotatable hub connected to the gondola and configured to support a plurality of rotor blades, the rotatable hub being operatively connected to the generator, and an air handling device, such as a fan or an air filtration system, in the gondola and/or in the hub.

Abstract: An assembly includes a fastening screw having an end surface and a substantially cylindrical side surface extending axially away from the end surface and a protective cap covering the free end. The cap has a first end opening from which the fastening screw extends, a second end overlying the end surface of the fastening screw, a side wall surrounding a portion of the cylindrical side surface, an inner surface defining a cap interior, and an outer surface. A cap screw extends through an opening in the second end of the cap and into a threaded opening in the end surface of the fastening screw to secure the protective cap to the fastening screw.