EQUIPMENT AT MOUNTAIN LAKES 



85 



Figure 20. Typical hydrophone mountings: (A) 1 A li\- 

 drophone, (B) 3A hydrophone, (C) XMX hydrophone. 



three-piece extension rods. The tipper section may 

 be adjusted over some 2 feet by means of a crank- 

 operated screw. The lower section is also adjustable, 

 but only in steps. Center sections of various lengths 

 may be inserted between these two ends. The upper 

 section has a square mounting plate set in gimbals 

 which permits the rod to hang vertically, if symme- 

 trically loaded. This plate rests on a shock-absorbing 

 receptacle and allows an assembly to face in any one 

 of the four directions. The lower section terminates 

 in a short crossbar that will accommodate various 

 coupling fixtures. Figure 20 shows a typical mount- 

 ing. 



Devices up to 1,500 pounds are suspended from 1- 

 inch extra-heavy pipe available in convenient lengths. 

 One end has a heavy-duty eye for the hoist hooks and 

 the other has standard pipe thread for attachments 

 such as flanges, yokes, T bars, and brackets. Figure 

 21 shows the more common fittings. Pipe is the usual 

 support for standard projectors rigged for semiper- 

 manent service and for those which are not rotated 

 for pattern studies. It is necessary to keep lengths that 

 are not in use hung vertically to avoid bending. 



Clamping block assemblies, designed for securing 

 the pipes at the required positions, are shown in Fig- 

 ure 22. Convenient features include: rapid locking 

 and release without separate wrenches, free angular 

 motion of 40 degrees between the block and its base 



Figure 21. Transducer suspension pipes. 



to orient the transducers, interchangeable antishock 

 mountings to suit the transducer loading, leveling 

 screws and built-in levels for trimming the entire 

 assembly to the vertical. 



Rotator. All test devices which require continuous 

 rotation for observation of beam patterns are sus- 

 pended from a rotator mechanism. The assembly may 

 be seen in Figures 23 and 24. The rotator has two con- 

 centric drive shafts that rotate either individually or 

 jointly in synchronism with the polar recorder turn- 

 table previously described in this section. Independ- 

 ent rotation of the concentric shafts is required for 

 studies of transducer-dome assemblies. For other 

 tests, a single shaft is sufficient. 



The housing of the rotator contains the driving 

 gears, radial and end-thrust bearings, and the me- 

 chanical clutch assembly. Each shaft has a clutch to 



Fk.ure '22. Special clamping blocks for holding suspen- 

 sion pipes on turret type carriage. 



