The wings are swept back to reduce the danger of fouling 

 by seaweed and debris. Provision is made for an instrument 

 capsule with a volume of about one cubic foot, to house equip- 

 ment required at the maximum depth. The volume of the housing 

 was selected arbitrarily and can be increased considerably 

 without significant change in the system characteristics. 

 Since the total weight of the body in water will be less than 

 1000 pounds, the additional static downforce required is pro- 

 vided by ballast weights „ This provision facilitates static 

 trim of the body and also increases the metacentric stability. 



The stability of the body has been treated only for the 

 static case. However, the margin of static stability, deter- 

 mined by past experience, should ensure satisfactory dynamic 

 stability. This and other towing characteristics of the body 

 can best be verified by limited tests in a towing basin. Such 

 tests are usually desirable in any event in order to make 

 final adjustments to ballast, location of tow point, and 

 settings of wings and control surfaces. 



The effect of variation in speed on downforce and drag 

 was calculated. Results, presented in Figure 4, show that 

 the cable angle at the body is about 84 degrees at the 

 design speed, this angle being arctan — , where L^ is the 

 total downforce and D the total drag. With decrease in speed, 

 the angle increases to a maximum of 90 degrees, since the 

 weight is a constant and the hydrodynamic forces vary 



28 



