Page 501 echo sounding 531S 



5373. Echoscope 



The Echoscope is a visual depth-indicating device designed especially for sounding in shoal 

 water. Like the Echometre, the depth-indicating device operates on the principal of the string 

 galvanometer oscilloscope and, except for minor differences in the optical system, the indicating 

 mechanisms of these instruments are quite similar. The principal features of this instrument are: 



(a) A depth range of 1 to 60 meters. 



(6) The use of high-frequency supersonic signals. 



(c) The instrument is portable, intended for shoal-vs-ater sounding from small boats. 



(rf) Use is made of a single quartz-crystal acoustic unit for both transmitting and receiving. This unit may be supported over 

 the side of the vessel or installed in its hull. 



(n) The depth-indicating device, echo amplifier, and high-frequency generating equipment for energizing the transmitting unit, 

 all in a single cast-metal cabinet. 



(f) An indicating device run by a spring-operated clock motor. 



(<?) All electric energy derived from batteries. 



5314. S.C.A.M.-Touly 



The depth-indicating part of this echo-sounding instrument is quite similar to the visual-indi- 

 cating instruments made in the United States. The indicating mechanism is housed in a metal box 

 in whose face a circular opening is cut, concentric with which is a graduated depth scale. Adjacent 

 to and just behind the scale is a rotating mirror carried on a radial arm. Light from a stationary 

 neon tube falls on the mirror and is reflected to the depth scale in such a way that a band of light 

 indicates the depth. The operation is as follows: As the rotating mirror passes the zero point on 

 the depth scale, a cam-operated switch causes the transmitting unit to be energized. From this 

 time until the echo is received the neon tube is not illuminated, but when the echo returns the neon 

 tube flashes and remains illuminated until it is extinguished at the zero of the depth scale. The 

 beginning of this illuminated arc is the measured depth. Some of the features of the S.C.A.M.- 

 Touly instrument are: 



(a) The use of high-frequency supersonic signals. 

 (6) A depth scale graduated from to 400 meters. 



(c) All operating energy derived from batteries. 



(d) The driving motor speed controlled manually. 



(e) A belt-driven centrifugal tachometer indicates motor speed by means of a needle moving over a scale. 



(/) A manually operated button by means of which transmission is suppressed at will; as, for instance, when it might interfere 

 with the reception of the echo when the depth is near 400, 800, 1,200 meters, etc. 



532. English Instruments 



Henry Hughes & Son, Limited, of London, England, manufactures a large variety of echo- 

 sounding instruments. This company makes both graphic-recording and visual instruments, uti- 

 lizing both sonic and supersonic frequencies. Some of the instruments are portable and some require 

 permanent installation. These instruments may be broadly classified as: 



(a) A graphic-recording instrument that makes use of sonic frequencies, the sound being produced by a hammer or striker. This 

 instrument is intended for use in moderately deep water and is known as the Challenger type. 



(6) The graphic-recording instruments of the MS class that make use of supersonic frequencies, produced and detected by means 

 of magnetostrictive units. A variety of instruments of this class is made, varying in maximum scale range from 70 feet to 4,500 meters. 

 Some of these instruments are portable, but others are for permanent installation. 



(c") A visual-indicating instrument. 



5321. Sonic Recording Instrument: Challenger 



The graphic-recording sonic instrument contains the following features: 



(a) The soimd is produced by a hammer or striker. 

 (6) The echo is recorded on sensitized starch-iodide paper. 



(c) A scale range of 250 fathoms with five phasing positions of 0, 200, 400, 600, and 800 fathoms, which values are added to the 

 recorded soundings. 



(d> The recording mechanism and echo amplifier are housed in a single cast-metal cabinet. 



5322. Graphic-Recording Instrument: MS Class 



All the MS type graphic-recording instruments record on a moist starch-iodide paper. In 

 some models a rotating radial arm carries a stylus that sweeps in an arc across the record paper, 

 while in other models the stylus is moved linearly across the paper at a constant speed, the stylus 



