INTRODUCTION TO SONAR 



NAVAL MESSAGE 



OPNAV FORM 21 10-28 [REV 3-t,\) S/N 0IO7-705-4OO0 



From: USS Fred T. Berry DD858 

 To: FLEWKAFAC NORVA 

 Info: CANMARCOM HALIFAX 



BATHY 31230 03742 06527 XX686 00647 14647 30694 40676 

 51619 54563 73552 90492 19991 



DISTRIBUTION 

 (Page One Onlv) 



UNCLASSIFIED 



DATE TIME GROUP (GCTi 



181406Z 



Figure 5-21.- 



31.47 

 BT massage. 



SEA SURFACE TEMPERATURE 

 REPORTS 



In connection with the antisubmarine warfare 

 environmental prediction system (ASWEPS), all 

 ships of the U.S. Fleet are required to record 

 the sea surface temperature (CTEM) every odd 

 hovir while at sea, commencing at OlOOZ (or the 

 first odd hour after leaving port) and ending at 

 2300 Z (or the last odd hour before entering 

 port). A radio message, containing the required 

 data, is transmitted daily after the final observa- 

 tion at 2300Z. As with BT messages, the ad- 

 dressee for CTEM messages depends on your 



ship's location. The message is sentimclassified, 

 with a priority precedence. 



Figure 5-22 illustrates the log on which to 

 record the sea surface temperatures. It is 

 filled in to represent the collective readings for 

 a single day. The message format is similar 

 to that used for a BATHY message. 



LOGGING PROCEDURE 



Information contained in the CTEM log is 

 similar to that entered in the BT log. Two 

 major differences are that only surf ace tempera- 

 tures are recorded, and the temperatures must 



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