as rapidly as possible „ The operator of the echo sounder -would watch the 

 leadline and as the lead struck bottom, mark a "fix" on the echo-sounder 

 recording and call "fix" over the radio to signal the shore stations to 

 cut in the horizontal position of the DUKW By utilizing this procedure 

 accurate leadline soundings were plotted every 45 to 60 feet and the echo- 

 sounder recordings were used to fill in details between successive lead- 

 line soundings „ 



The characteristics of submarine canyons make this sounding technique 

 practical „ The relatively steep slopes of the canyon are usually firm sand, 

 clay or rock thus eliminating the possible objection of sinkage into the 

 bottom of the 100-pound lead weight,, 



It is believed that the combination of leadline and echo sounder 

 methods described provides a satisfactory means of obtaining relatively 

 accurate depth information on the slopes of submarine canyons or other very 

 steep submarine slope s„ 



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