built into the interior of the pyramid. The positively buoyant 

 platform was connected with a Benthos acoustic release to 300 m 

 of 3/8" wire and a 1000 kg anchor of scrap steel. A 

 polypropylene line ran from the platform to a surface float for 

 location of the mooring by the submersible. 



Two sets of 12 V lights were mounted on two top corners of 

 the pyramid, a low power pair of 20 watt lamps, and a high power 

 pair of 100 watt lamps. These were powered from a battery box 

 containing 6 12-volt deep-cycle batteries immersed in mineral 

 oil. Each pair of lights could be switched on and off from the 

 surface ship through acoustically controlled auxiliary circuits 

 in the Benthos acoustic release. The low power lights were 

 intended to be turned on from the surface before a dive to 

 attract zooplankton and micronekton to the platform. Once 

 activated, they would remain on for 4 hours, but could be turned 

 off from the submersible via a switch mounted on the platform. 

 The high power lights were intended to illuminate organisms when 

 the submersible was at the platform. They were turned on and off 

 acoustically from the surface, with visual confirmation by the 

 submersible. 



A hook on the platform was provided to hang baited traps. 

 One trap was deployed on dive 1422, but nothing was found in it 

 when the platform was recovered. 



The submersible was launched on July 12 from the Twin Drill 

 at 32°23'N adjacent to the bottom station established by 

 Grassle. When first visited on Dive 1420, it was found to be 

 moored at exactly 1000 ft (330 m), with the anchor secure on a 

 small patch of level bottom. Efforts to turn on the low power 

 lights from the ship were unsuccessful, evidently because of a 

 relay malfunction at the platform. The high power lights were 

 turned on and found to provide excellent illumination of small, 

 transparent zooplankton. On dive 1421, we were unable to locate 

 the platform at night. The platform was located again on dive 

 1423, when the high power lights were found still burning after 

 an earlier attempt to find the mooring. After 60 hours of 

 continuous operation the batteries were nearly exhausted. A 

 change in the weather forced us to move to the south side of 

 Bermuda after dive 1423, and we were unable to make any further 

 dives at the platform. It was recovered on July 21 by the 

 Twin Drill , disassembled in Bermuda and shipped back to Woods 

 Hole. 



Despite these problems, we felt that the concept of a 

 station moored in midwater was adequately tested, and with 

 improvements, it will be a useful tool for future programs. 



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