(12) This velocimeter was originally designed for use on submarines and 

 a large number has been delivered to the Navy. Its oceanographic 

 version, "Depth-sound Speed Measuring Set," including a pressure 

 gauge, is described here. 



(13) On a 20 cm path, 3 MHZ pulses at crystal controlled 32.4 KHZ repeti- 

 tion rate travel from transmitter to receiver. The phase of their 

 arrival determines the duty-cycle of a flip flop, thus providing an 

 analog DC output. 



(14) In transit case. 



(15) Made by Plessey, England; sold in the US by Hytech Marine products, 

 the Bisset Berman Corp., G-Street Pier, San Diego, California 92101, 

 Tel: 714-234-6755. 



(16) Hytech supplies two different models, one to produce an output fre- 

 quency directly proportional to the speed of sound in ft/sec (M030) 

 and the other in m/sec (M031) . 



(17) As measured at 25 knots, according to Hytech, this is a particularly 

 small value due to the use of one transducer with folded path, thus 

 letting the pulse travel around an exactly closed path. 



(18) Recent company-issue sales literature should be consulted. The 

 quoted open-literature references are necessarily somewhat dated. 



(19) Only 2" diameter. 



(20) Approximate price, including power-supply on deck. 



(21) According to "Informal Manuscript Report" 1-04-65 (unpublished) , 

 Naval Oceanographic Office. 



(22) According to private communication from Dyna-Empire (1966) . 



32 



3rtbur ZD.lUttlc.Knr. 



