Abstract: A submersible buoy adapted to be attached to a submersible object via a line is disclosed with a central body having a first end and a second end axially spaced apart, the central body adapted to have the line wound therearound. A first and a second floater units are connected to the ends of the central body and have a first buoyancy and a second buoyancy being of a value relative to the first buoyancy such that a total buoyancy force exerted on the submersible buoy, at equilibrium when submerged, is substantially perpendicular to a central axis of the buoy. A line release mechanism includes a line retention device operable between a closed position and a released position, retaining the line to prevent unwinding of the line, and releasing the line to allow the line to unwind, the line release mechanism being operatively linked to a controller unit controllable remotely for remote actuation of the line release mechanism.