Mode 3 



This mode is used to determine wave heights by measuring the time required 

 for sound pulses to reach the water surface and return to the submarine; however, roll 

 angle or heave measurements can be made also. 



Figure 1 is a block diagram of the operational system, showing the transducer and 

 recording relationship. Also shown are Modes 1 and 3 with their options. 



II. SYSTEM DESCRIPTION 



A. General 



The System consists of sensors for measuring the appropriate variables, dig- 

 itizing components to convert sensor outputs to digital form where required, displays 

 for all recorded information, a scanner to feed the information alternately from each 

 sensor to the recorder or tape punch, a digital recorder for optional use in lieu of 

 the tape punch, and a tape punch to make a permanent record of the recorded vari- 

 ables for direct input to the Hydrographic Office digital computer. A Flexowriter 

 can be added, for verification of tape punch data In the field. The oceanographic 

 console is shown in Plate 1 and Figure 2. Plate 2 shows the individual components 

 of the system . 



B . Transducers (shown on Plate 2) 



The vibrotron, sound velocity, thermister, and fathometer transducers are 

 all mounted in a single transducer housing as shown in Figure 3. This housing 

 requires a single foundation and can be mounted anywhere on topside of the subma- 

 rine in the free flow of water. On the ARCHERFISH,the transducer housing is 

 mounted on the forward gun mount deck near the number 48 frame . 



Pressure (depth) is sensed by a vibrating wire transducer (vibrotron) in the sensor 

 housing. Its output is a frequency inversely proportional to depth. This instrument 

 has undergone repeated tests aboard the REDFIN without a single failure. 



Sound velocity is obtained from a Bureau of Standards velocimeter located In the 

 sensor housing. This instrument was found to be quite reliable during shipboard oper- 

 ations. The output of this transducer Is a frequency which is directly proportional to 

 sound velocity in meters per second. 



Temperature is measured with a temperature probe consisting of dual thermister 

 elements. Output of the bridge is a voltage which is directly proportional to tem- 

 perature. The thermisters were tested both in the laboratory and aboard the REDFIN 

 and yield accuracies better than - 0.1*C. 



