Andrews 



or reinvestigate any contact. Instead, if the contact looked pood 

 on the OBSS trace readout, it was reported by radio to the control 

 ship. Thus the navigation error of detection ship and classification 

 ship were accumulative, possible communication errors could be intro- 

 duced and no opportunity was given to the OBSS operators to learn 

 whether the targets they were reporting were good or bad. As a 

 result there are only 13 OBSS contacts in the OC class. Of this 

 number 9 were rocks. Of the 66 OBSS contacts in the OD category, 39 

 were reported or followed up by units with no DECCA, and 32 were 

 reported in areas later determined to be high density areas (i.e. > 

 5 visual sightings/ 1/4 mile sq.). 



2. The UQS-l was of limited use on independent broad area 

 acoustic search and only in shallow water (i.e. < 300 feet). 



Specifically, the minesweeps with UOS-1 carried out certain 

 mine-hunting tactics in which a contact was regained several times 

 before it was considered a valid detection. Thus the percentage of 

 UQS-l contacts (16/34) in the OC category v/as an improvement over 

 the OBSS. Still the inability to know whether the contacts reported 

 were good or bad preempted any learning process by which the sonar 

 operators could improve their skill. 



A second tabulation Figure 9, shows the performance of visual 

 identifiers. The significant conclusions from this study were: 



1. Cubmarine, and the EOD/UDT divers were the leaders 



in sightings of aircraft debris in All. The relative 

 immobility of hard-hat divers and "dipped" TV, and 

 material problems with DEEP JEEP accounts for the 

 poorer sighting performance of these three elements. 



2. The team combination of a minesweep with UOS-1 and 

 the EOD divers or Cubmarine was a most successful 

 method for searching acoustically and simultaneously 

 identifying a target. Mr. Barringer, Senior Pilot of 

 Cubmarine, indicated that Cubmarine was vectored to 

 75% of the contacts listed in Figure 9. This is a 

 significant fact since it correlates with a report by 

 COMIN DIV 84 that the ability of his UQS-l operators 

 to distinguish rocks from debris increased signifi- 

 cantly when they received back an immediate report 

 from Cubmarine or an EOD diver concerning the nature 

 (rock or debris) of the target which had just been 

 obtained acoustically. A tabulation of sea scanar 

 performance (not given here) showed that this sonar 

 mounted on a small boat and teamed with divers was 

 also relatively effective. 31 acoustic contacts 

 were made of which 24 visual sightings were made in 

 the immediate follow-up. However, over 40% of the 

 contacts sighted were rocks. A major difficulty was 



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