MARCONI ECHO METER TYPE 429

ABOVE IS THE MARCONI MARINE ECHOMETER ELECTROLYTIC RECORDER, TYPE 429.THIS WAS A DEPTH RECORDING DEVICE WHICH RECORDED ONTO SPECIAL SENSITISED PAPER.THE ROLLS OF PAPER WERE 7 1/2" WIDE.A PULSE WAS SENT FROM A TRANSDUCER ON THE BOTTOM OF THE SHIPS HULL TO THE SEA BED AND THE RESULTANT ECHO WAS TIMED AND DISPLAYED ON THE PAPER IN GRAPH FORM.