Apparatus and methods for mixing the contents of manure storage lagoons. Remotely controlled floating agitation vessels are provided. Some have one or more propellers which are located on the ends of agitator arms where the propellers are driven by motors located at the opposite ends of the arms and having a drive shaft extending through the agitator arms. The agitator arms can be lowered and raised varying degrees and have the propeller speeds varied both under remote control. Some apparatus are steered using a steering arm coupled to a land secured cable where the orientation of the boat is changed by pivoting the steering arm angle with respect to the cable. Some apparatus are remotely steered by remotely and individually controlling the speed of the propellers. Propeller motors and actuators can be hydraulically driven with the hydraulic fluid and driving engine air cooled using a radiator.
