Depth measuring apparatus for a dredger

A depth measuring apparatus for a dredger having an arm and an attached scoop, comprising an inclination sensor mounted on the dredger arm for generating an inclination signal indicative of the inclination of the dredger arm,

• a receiver, fixedly secured to the dredger arm, for a radiation transmitter establishing a reference level and said receiver comprising a plurality of receiving units disposed at different levels one above another each to generate an output level signal when impinged by a radiation, and an evaluation circuit connected to said receiver and said inclination sensor, wherein said receiver is operative by its receiving units to determine the relative vertical position of the radiation establishing said reference level with respect to said receiver, and to generate said output level signal indicative of said relative position, and
• wherein said evaluation circuit is operative to generate a signal indicative of the depth of the dredger scoop relative to said reference level from said inclination signal and said level signal.