±0.5 fathom (3 feet) or better over the entire operating range. 



c. Power Supply: 



(1) Should be capable of both a. c. and d. c. operation. 

 (Z) Should be equipped with a frequency meter and voltage 

 regulator . 



d. Transducer (s): 



To include two (2) transducers of different frequency ranges, 

 for the purpose of obtaining fine resolution of bottom detail as well 

 as reliable performance under severe environnnental conditions. 

 These transducers are to be enclosed within the same streamlined 

 housing. 



e. This system should include a streamlined housing for the 

 dual transducer plus a streamlined sword-arm for supporting the 

 transducer housing assembly. The transducer housing, the sword- 

 arm, and associated support arms should be streannlined, light 

 weight, of simple design, rugged, and easy to rig and unrig. Addi- 

 tionally, the entire assembly should be designed to permit installa- 

 tion on either side of the small craft/launch, at the bow or stern, 

 and with a capability of positioning the transducer housing at any 

 depth between Z-10 feet below the surface of the water. 



f. Rec ording : 



(1) To provide a graphic recording of the bottom, in feet 

 and in fathoms. 



(2) Scales: 



(a) 0-100 feet. 



(b) 0-600 feet. 



(c) 0-1, 500 feet. 



(3) Recorder design should emphasize ruggedness, simpli- 

 city, compactness, ease of maintenance, and ease of annotating the 

 recording trace. 



g. The transducer housing and sword-arm should be designed 

 so that they can readily and easily be shipped and unshipped by two 

 men. The same applies to the power pack-recording unit. 



370 



