copper wiring, insulation, and copper grounding coupled with the other 

 cited defects were responsible for the operation of some sets at about 

 fifty percent of their theoretical output. 



Radio Direction Finding Equipment 



Radio direction finding equipment is considered to be of little 

 value in the shrimp fleet at the present time. In the past, many of the 

 larger vessels crossing the Gulf on the Campeche run had this equipment 

 installed. It was found, however, that radio bearings were of limited 

 accuracy at a distance, especially if the loop was an inside installation. 

 Many captains would not turn the vessel to a position where the bearing 

 could be taken without interference from the rigging. Few captains have 

 been trained to make proper bearings and fewer still have been trained 

 in tne more advanced principles of navigation; information obtained from 

 the direction finding equipment, therefore, is seldom used. 



Depth Sounder with Cathode Ray Tube 



A depth sounder with a cathode ray tube designed to function 

 as a fish or shrimp finder is sometimes installed in the larger vessels. 

 Supersonic signals transmitted downward are reflected back from the bot- 

 tom schools of fish, and a clear visual indication is obtained on the 

 cathode ray tube. Normal maximum range is 320 fathoms. 



The practical value of this type of sounder from the standpoint 

 of tne shrimp fishemian has not as yet been clearly established. Research 

 workers associated with the northeastern trawl fishery report that it 

 takes captains from three to four months to get the feel of the instru- 

 ment. So far shrimp vessels have not given the sounder this type of trial. 



There is a possibility that the sounder might come into use 

 once deep water fishing for Royal Red shrimp becomes more common. In 

 deep water operations the instrument would view the bottom far enough 

 in advance of the trawl to permit the skirting of major obstructions. 



Loran 



Loran is an electronic device which gives an accurate long 

 range fix (750 miles by day, 1,500 miles by night, under ideal conditions). 



The equipment operates satisfactorily, although in the Texas 

 Area its use is limited by low signal strength from the master and slave 

 stations in the eastern Gulf. 



As with all electronic equipment, it is important that the 

 firms installing loran provide the fisherman with adequate instruction 

 in the use and maintenance of the device. The effective utilization of 

 the device depends on the availability of competent repair service and 

 trained crews. 



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