of the flow of water around the bow they 

 were not fully effective and subsequently 

 were moved aft where they provided better 

 control. While this trial-and-error approach 

 may appear somewhat unsophisticated, 

 there are no better guidelines available and 

 Mr. Cunningham's concluding statement 

 fairly well sums up the pragmatic approach 

 private builders have taken in an area void 

 of precedent: "It works!" 



The shape and location of rudders and 

 planes, and combinations thereof, vary from 

 vehicle-to-vehicle, but a sampling of the dif- 

 ferent approaches can be obtained from the 

 following examples: 



PC-3B (Fig. 8.9) is equipped with a rectan- 

 gular rudder which is manually turned left 

 or right. Plexiglass bow planes, similar to 

 those on DEEP DIVER (Fig. 8.10), control 

 pitch. 



Martine's SUBMANAUT (Fig. 8.11) com- 

 bines both rudder and planes into a stern- 

 mounted arrangement whereby yaw and 

 pitch are obtained. 



SEA OTTER (Fig. 8.12) had a rudder ar- 

 rangement similar to Perry's PC-3B, but 

 both rudder and propeller were shielded for 



protection. This is now replaced by a Kort 

 nozzle. 



DEEP QUEST (Fig. 8.13) obtains yaw and 

 pitch motion with hydraulically actuated 

 rudder and stern planes. An automatic pilot 

 system with integrated controls (discussed in 

 Chap. 2) can "fly" the vehicle on a predeter- 

 mined course, pitch angle and altitude. 



The DSRV submersibles (Fig. 8.14) employ 

 a unique pitch and yaw system. In this sys- 

 tem a stern-mounted shroud encircles the 

 main propeller which may be tilted fore and 

 aft from the vertical and left and right, thus, 

 combining a rudder/plane system in one unit. 

 The shroud is not designed to redirect the 

 propeller's thrust, but to orient lines to flow 

 as does a rudder. Figure 8.15 shows the 

 variation of shroud lift conditions with angle 

 of attack for various aspect ratios as calcu- 

 lated by Lockheed during design of the 

 DSRV 8. 



There is another system of pitch control 

 which many vehicles with cylindrically- 

 shaped hulls obtain by virtue of their small 

 metacentric height. This consists merely of 

 the occupants leaning or moving fore or aft 

 within the vehicle. While such tenderness 



Fig, 8.9 The PC-3B is provided yaw motion by its stern rudder and pilch by plexiglass bow planes not visible here. (NAVOCEANO) 



378 



