The deployment of the FLS with the Johnson Sea-Link 

 involves attaching the flume to the wrist of the sub's robotic 

 arm. The deployment necessarily occurs at a distance of 2-3 

 meters from the cockpit observers; this distance, combined with 

 poor visibility conditions and the reducing lens effect of the 

 Plexiglas sphere, has made it necessary to attach a small video 

 camera to the wrist of the hydraulic arm. The cockpit observers 

 can put the flume into a roughly horizontal position and bring it 

 to within a few decimeters of the sediment-water interface before 

 using the wrist camera. The flume must be emplaced very slowly, 

 with the hydraulics of the arm turned down as far as possible, in 

 order to avoid a bow wave effect from the descending flume. The 

 small height of the flume when emplaced, coupled with the need to 

 position the trip bar exactly on the sediment-water interface, 

 require +/- 1 mm accuracy in positioning in order to obtain the 

 u distribution measured in the laboratory. This fine 

 positioning is at the limit of the capability of the sub, and 

 often many tries are necessary before a good emplacement results. 

 A common problems is a "dust cloud" set up by the sub during the 

 landing process, which is solved by pointing the sub into 

 whatever current is present and slowing inching the sub forward 

 after landing. A second problem is hydraulic creep of the arm 

 during the pumping process, which can lead to several mm of 

 vertical movement of the flume during several minutes, which 

 could occasionally be solved with fine-tuning of the hydraulics 

 by the sub pilot. 



After the flume is satisfactorily emplaced, the operator 

 turns on the pump and monitors the flow meter inside the cockpit. 

 Good stability of flow (+/- 10 - 15%) for many minutes was 

 obtained. 



The Delta system deploys the lander-flume assembly by 

 suspending it from a block on the bow plane; the assembly is 

 lowered by the sub pilot with a manual pulley system under 

 direction from the scientist/operator. Potential dust cloud 

 problems are solved in the same manner as for the JSL, with a 

 soft landing followed by inching into the current. The Delta 

 system allows direct observation of the flume by the scientist/ 

 operator, due to a distance of no more than a meter and no 

 reducing lens effect. The manual lowering allows for a very 

 slow descent, and no bow wave problems are encountered. The 

 weight of the lander interacts with the firmness of the sediment 

 to control the depth to which the lander-flume assembly 

 sinks into the sediments; it is necessary, therefore, to keep the 

 negative buoyancy sufficiently low to avoid too great a 

 penetration of the flume into the sediments. The final insertion 

 into the sediments, then, is accomplished by the scientist, using 

 the mechanical arm to push the assembly down. The magnet with 

 which to trigger the motor is mounted at the end of the same arm, 

 and the magnet is simply held next to the target on the aluminum 

 housing for the desired time. 



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