Haselton 



DISCUSSION 



LCdr A. Skolnick 



Deep Submergence Systems Project Office 



Chevy Chase, Maryland 



The author has stated privately that the historical event to which his first 

 sentence refers is Moses in the Red Sea. One can think of at least one other 

 biblical instance, i.e., Jonah, where the doubly aggravating circumstance of be- 

 ing in the depths of a whale in the depths of the sea was the case. The prospect 

 of mating a deep-diving manned submersible on the hatch of a distressed sub- 

 marine is in a sense an aggravation of the third power. The rendezvous and 

 docking of two vehicles in outer space is less difficult; the visibility is good 

 there, but this is hardly the case for the submersible; the space docking occurs 

 unbuffeted by winds, whereas underseas chaotic flow conditions can take place 

 as a result of water currents and the effect of local protuberances; finally, 

 space vehicles are smartly responsive, whereas submersibles are well noted 

 for their sluggishness. The requirement of mating upon an underway or hover- 

 ing mother submarine (present in support of the operation) portends no lesser 

 task than the requirement of mating upon the distressed ship. 



The author is correct in underscoring the necessity for developing large 

 control forces rapidly; no amount of control system sophistication or human op- 

 erator unburdening can compensate for a lack of performance upon demand. 

 Without proper power available, control augmentation devices merely become 

 additional "cargo" and their purpose is severely compromised. Members of the 

 audience familiar with the effects of transportation lag (pure time delay) upon 

 automatic control systems can well imagine the situation when a human pilot is 

 introduced into the loop. Any action taken to alleviate long response times is 

 sure to contribute to success in operation. Finally, one wonders about the whole 

 business of analytical description and electronic analog simulations vis-a-vis 

 the accuracy of the hydrodynamics model for near -zero velocity operation. The 

 controls engineer has made great strides in the last 15 years and stands at the 

 ready — it is past time for the hydrodynamicist to develop valid zero-velocity- 

 regime -describing functions so steady team progress can be made in this rap- 

 idly developing field. 



312 



