Maintenance of True Bearing , 



Another most important Improvement to existing sonar gear 

 resulted from the development of the Maintenance of True Bear- 

 ing (MTB) system. This device enabled the sonar operator to 

 maintain his projector automatically on any desired bearing 

 with respect to true North, regardless of the movement of his 

 ship,, With MTB the operator had only to adjust the training 

 hand wheel to correct for gradual changes in the true bearing 

 of the target, instead of having to keep up with rapid changes 

 in relative bearing as the ship maneuvered., 



The work on MTB was carried out at the New London Lab- 

 oratory,, 



Receiver Console . 



These devices together with a number of other still clas- 

 sified improvements were incorporated in an echo-ranging re- 

 ceiver console o The arrangement of components in the old 

 style sonar rack, with the range and bearing indicator widely 

 separated from the most important operating controls , made it 

 difficult for the sound operator to observe and control the 

 equipment „ The new rack, of console type, permitted a con- 

 centration of the most important indicators and operating 

 controls in a location convenient for a seated operator and 

 allowed greater accessibility to all the components for main- 

 tenance and repair c This new arrangement markedly increased 

 the range and bearing information obtainable per unit of time,, 



These developments were carried out by the Columbia Uni- 

 versity Laboratory at New London and by the Harvard Underwater 

 Sound Laboratoryo By the end of the war all the principal 

 manufacturers of sonar equipment were in production on console 

 types of echo-ranging gear c 



Sonar Testing Equipment , 



To design and build improved sonar gear was only part of 

 the task of Division 6, Once the equipment was installed there 

 was the problem of seeing that it worked and that it kept on 

 working at maximum efficiency,, 



82 



