650'- 

 TEMP, 



1,5 00- 

 TEMP 



DISTANCE H 10 nautical miles *\ 



Figure 9. — Complex temperature structure over a distance of about 45 nautical miles 

 (85 km.) in the western boundary of the California Current. 



FURTHER DEVELOPMENTS 



Subsequent to the shakedown cruise, the 

 Sippican Corporation recalled the XBT system 

 for re-engineering. The model T-4 probe was 

 developed to improve the wire insulation and 

 to assure better response of the thermistor 

 at the time of water- entry. 



The modified XBT system was installed 

 aboard the SS CALIFORNIAN on June 1. By 

 early November 1966 the ship had completed 

 nine round trips. During this period observa- 

 tions were taken for 10 sections; 1 outbound 

 and 8 inbound sections between San Francisco 

 and Honolulu and 1 special outbound section 

 from Los Angeles to Honolulu. The system 



was removed from the ship for one trip to 

 repair the digitizer. 



On the basis of preliminary analyses of 

 these traces, the modified system is more 

 reliable than that used on voyage 105. The 

 defects causing the near-surface irregularities 

 appear to have been remedied, so that the 

 traces in almost every instance show rapid 

 response of the system when the probe enters 

 the water. 



The percentage of total failures has been 

 8 percent as compared with 11 percent on 

 voyage 105. A few of these failures may be 

 attributed to poor insulation on the wire of 

 the T-4 probes. Most failures occurred be- 

 cause the recorder did not trip and go through 



