Design of the Towed Body 



Two methods may be used to produce the downforce required 

 on the bottom end of the cable. One is to attach a stable 

 towed body, with weight in water equal to the required force; 

 the other is to employ the hydrodynamic force produced by 

 depressing wings attached to the body. 



Disadvantages of using weight alone are: 



1. The heavier the body the more difficult the 

 problem of shipboard handling; and 



2. With constant weight and a given cable length, 

 depth of tow decreases with increase-in speed. 



Advantages of using weight alone are: 



1. The towed body is less responsive to disturbances 

 from the flow and from motion of the towing vessel; 



2. Design of the towed body is less critical and less 

 difficult; 



3. The body is less subject to serious damage in handling; 

 and 



4. Accelerative forces during launching and retrieving 

 while under way are less severe than transient hydro- 

 dynamic forces experienced with a winged body. 



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