Abstract: The automatic diving tending system (ADTS) includes a buoyant sealed torsional apparatus having a plate with a perimeter seal to which is affixed a cover with a perimeter flange forming a dry buoyant cavity. On the plate is mounted a bridge supporting a drive shaft, a locking mechanism, a constant torque spring motor, and an overdrive transmission linkage. A tether spool apparatus is mounted on the exterior bottom side of the plate. It includes a frame with a guide, a spool, and coaxial connecting structure that connects to the drive shaft. A line wound on the spool that is pulled off tightens the spring motor, enabling the full length of the line to be rewound back onto the spool and to be stopped at any time by a diver.