OCEANOGRAPHIC INVESTIGATIONS 



351 



stake near the current meter, were unsuccessful. A concerted search of the nearby area was 

 made, but the instrument was not found. The failure to recover this instrument resulted in a 

 serious loss of valuable data, since it contained the only data made away from Sealab suitable 

 for correlating with thermograph data made at Sealab. 



Temperature variation as a function of depth were provided by a standard shallow -water 

 bathythermograph (BT). During occupancy of Sealab by Teams 1 and 3, the writers made BY 

 lowerings from the surface-support vessel. During Team 2's occupancy the writers obtained 

 BT data by operating the instrument in an "upside-down" manner from the bottom. This was 

 done by attaching a flotation bag to the BT, which provided sufficient buoyancy to raise it to the 

 surface. Also attached was a nylon line, which with the aid of a small hand winch, allowed just 

 as easily as from the surface. Additionally, BT's taken from the bottom yielded somewhat bet- 

 ter traces in general than those taken from the surface. This was due to the fact that "upside- 

 down BT's" did not exhibit the scratches typical of BT's taken from the surface. Fig. 131 shows 

 a comparison of BT's taken from the bottom and surface. In all, 45 BT observations were made, 

 six of which were made from Sealab. 



II Up' 



Fig. 131. A comparison of surface and 

 bottom-taken bathythermographs. Upper 

 slide was nnade from the Surface Support 

 Vessel; lower slide was taken from Sea- 

 lab II 



During Sealab's occupancy, the surface temperature varied from 18° to 21°C (65 to 70-F) 

 with temperatures in the range of 19° to 21 °C (67° to 69 °F) predominating. Bottom tempera- 

 tures varied from 11° to 14°C(52 to 58°F) with temperatures in the range of 12° to 13°C (53° 



