Page 499 echo sounding 529 



The magnetostrictive transmitting and receiving units are similar in design to those of 

 the Veslekari graphic-recording instrument (see fig. 109), except that they are of less- 

 cylindrical length and the reflectors are smaller. All required power is furnished from 

 a storage battery of about 200 ampere-hour capacity. 



529. Blud WORTH Depthometer 



The echo-sounding equipment manufactured by Bludworth Incorporated of New 

 York was designed specifically to meet the requirements of the United States Corps 

 of Engineers in their surveys of inland waterways, dredged channels, and other areas 

 of comparatively shallow depths. This is a recording type of instrument, model- 

 ES-1000. It is not portable. 



Separate magnetostrictive transmitting and receiving units are used, similar to 

 those of the Hughes MS 12 D (see 528 and 5273). These units may be installed inside 

 a steel hull in a waterfilled compartment, their signals penetrating the hull plates, or a 

 streamlined housing containing the units may be supported outboard. The inside 

 installation cannot be used with a wooden hull, unless a hole, closed by a metal plate or 

 diaphragm, is cut in the hull. The transmitting unit is shock-excited by condenser 

 discharge, a gas-filled trigger tube furnishing the relay action for discharge. 



The echo amplifier uses three thermionic tubes with adequate filtering to permit 

 the passage of the frequency at which the magnetostrictive transmitting and receiving 

 units are tuned. 



The fathogram is made on a facsimile type of paper with a piinted scale, by means 

 of a stylus carried on a rotating disk. Four different paper speeds are provided, 1%, 

 2}^, 3%, and 5 inches per minute. The speed of the synchronous driving motor is con- 

 trolled by a governor that operates on the d-c motor of a d-c to a-c motor-generator 

 set, thus controlling the frequency of the a-c power that runs the synchronous driving 

 motor. The motor speed is registered on a frequency meter that is calibrated in cor- 

 responding revolutions per minute. 



A phasing control is arranged to permit extending the depth range of the fathogram. 

 The initial phase is to 60 feet, which is the limit of the printed scale. Thi-ee addi- 

 tional phase positions add 50, 100, and 150 feet respectively to the initial position. 



The recording mechanism, eclio amplifier, and numerous controls are all located 

 in a cast-metal cabinet. 



This echo-sounding instrument possesses several unique features, as follows: (l)^ 

 Variable control and indication of driving motor speed, so that adjustments may be 

 made to compensate for the variation in the velocity of sound in water, thus eliminating 

 the necessity for subsequent corrections due to velocity deviations (see 561 and 5616). 

 (2) Control to correct soundings for height of tide. (3) Control to correct soundings 

 for draft, and squat and settlement (see 551 and 553). (4) A clock on the face of the 

 recorder cabinet by which the time is recorded on the fathogram at minute and hourly 

 intervals. (5) The travel of the paper is stopped while the stylus is passing over it, 

 thus reducing distortion of the record due to the motion of the paper. 



53. FOREIGN ECHO-SOUNDING INSTRUMENTS 



The fundamental principles of operation of echo-sounding instruments of Europeans 

 manufacture are the same as for those made in the United States, the principal differ- 

 ences being the manufacturing methods peculiar to each country and the types of the. 



