Performance report of the first deployment of the NGK Automated Elevator System and the Optimare/Sea-Bird Electronics CTD-Logger in the Greenland Sea.

Fig. 1: NGK Automated Elevator System with an added buoyancy slice of syntactic foam and the Optimare/Sea-Bird Electronics CTD-logger on top before deployment in 2007. (Photo: Gereon Budéus AWI) (Photo: Alfred-Wegener-Institut)

The Automated Elevator System by NGK, Japan, consists of a sophisticated combination of an underwater winch, a control unit, multiple parallel power supplies, and a structure of frame and buoyancy. It is intended for the use in the open ocean where it has to reside in a depth smaller than 300 m and enables measurements right into the ocean surface. This important inclusion of the surface layer poses severe problems to mooring designs, and no commercially available operational alternative to the NGK solution is apparent. When the NGK system pays out rope, a buoyant instrument ascends until it reaches the water surface proper. The winch is halted then and reverses it’s rotational direction, thus moving the instrument back to it’s parking position close to the winch. A tension sensor in the elevator system detects the instrument’s arrival at the surface. Our mooring in the Greenland Sea is the premier use of the NGK system in Europe.