20120266480 | DEPTH DETERMINATION APPARATUS - A depth determination apparatus is described. The depth determination apparatus includes a rotatable reel for receiving a length of line, a free end of the line being adapted to receive a weight, a hollow elongate leader assembly through which the line is played out and retracted, a measuring arrangement for measuring the length of line played out and/or retracted through the hollow elongate leader; and a drive means for at least retracting the line through the hollow elongate leader. | 10-25-2012 |