DISCUSSION AND CONCLUSIONS 



Adverse weather and sea surface conditions affect 

 the motions of all floating platforms, particularly the 

 smaller vessels. Oceanographic ships are usually de- 

 signed to be just large enough to meet general needs, the 

 shape, length, and tonnage all being adjusted to keep down 

 the operating costs. Many such vessels, particularly of 

 United States registry, are less than 200 feet long. 

 Moderate to rough seas are therefore unkind to the people 

 that operate them and to the scientific equipment lowered 

 over their sides. 



Although weather and sea state are given considerable 

 attention in the planning of oceanographic studies, storms 

 can never be completely avoided on long cruises. Man has 

 therefore had to learn to live with and tolerate adverse 

 conditions at sea in order to gather the data he needs. 



The depth regulation equipment described in this re- 

 port makes possible many oceanographic operations without 

 any attempt to control erratic ship motions; instead the 

 latter are sensed and corrected for in the winch operation 

 only. Some examples of applications of the equipment 

 follows . 



Deep-sea cameras can be programmed, before they 

 are lowered and positioned by sonar, for definite periods of 

 hovering time at preselected target distances. Depth can 

 be automatically controlled to 1 or 2 feet, regardless of sea 

 surface state (fig. 6), permitting better bottom photo cover- 

 age with fewer blank frames. Film can thus be utilized 

 more efficiently in the production of continuously recorded 

 data. 



Precise depth control is not limited in its use to 

 underwater cameras. Water bottles, large and small, can 

 be held to constant depth until tripped or activated. Other 

 oceanographic equipments that require depth control are 

 thermistor beads for temperature recording, salinity units, 



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