Abstract: A small motor powered boat guidance system is disclosed and includes an arrangement for sensing the vertical distance between the boat and the bottom of a body of water in which the boat is floating and for providing a visual indication of the sensed vertical distance. A first series of visible pulses and a second series of visible pulses of the same frequency as the first series of pulses are generated with the pulses of the first and second series being interleaved and with the phase difference therebetween being indicative of the vertical distance. The visual indicator also generates, simultaneous with the visual indications, electromagnetic radiation in a region of the electromagnetic spectrum remote from the visible portion of the spectrum.

Abstract: Automated constant depth steering and automated yaw correcting techniques for fishing boats or similar craft usable in concert or separately are disclosed. The constant depth steering arrangement controls a relative constant thrust electric trolling motor by varying the orientation of this trolling motor which propels the boat relative to the boat. The constant depth steering arrangement includes operator entry switches and potentiometers for receiving an operator selected water depth and an indication of the direction and sense in which water depth changes. The automatic yaw correcting arrangement includes a rudder-like structure for sensing the lateral component of craft motion relative to the water, and is responsive to the sensed lateral motion to imparting a lateral thrust to the craft in opposition to the sensed lateral component of craft motion.