DMO - Model Wirewalker -Vertically Profiling Instrumentation-Platform

The surface buoy’s primary function is to harvest the energy from the surface wave field. The surface buoy also acts as a platform for real-time satellite GPS tracking of the Wirewalker’s position and can be equipped with a real-time telemetry system via Iridium or GSM. The surface buoy has been designed for optimal handling and efficient operation in a wide range of wave conditions. It comes equipped with a flasher (aka strobe) for deployment and recovery operations. The use of a positioning beacon is strongly recommended. 

The Wirewalker profiler travels along a jacketed profiling wire that links the surface buoy above, to the downweight below. This wire transmits surface wave energy deep into the sea through its mechanical motion. The length of the wire, along with turnaround bumpers attached near each end, define the upper and lower limits of the profiling range. In addition to providing motive power, the jacketed profiling wire also enables use of an inductive communications link between the moving profiler and the surface float.

The profiling vehicle (the “Wirewalker”) consists of the instrument platform itself, including the cam mechanism that selectively engages the profiling wire when descending. The cam mechanism drives the profiler downward, using wave action, to the end of the profiling wire, at which point the cam releases, allowing the profiler to float freely up to the surface. The profiler houses a configurable set of oceanographic sensors as well as a configurable set of depth rated foam to set the positive buoyancy. Various foam densities are available and define the depth rating of the profiler (300m-1000m). The profiler is outfitted with asymmetric cowlings that give it a leading and trailing edge as they align the profiler body into the current. 

The downweight is suspended at the bottom of the jacketed profiling wire, just below the profiler’s lower turnaround point. Typically, two steel downweight plates totalling 40 kg (90 lbs), is sufficient to ensure that the profiling wire maintains the tautness needed for proper profiling of the water column. There are four mounting holes in the plates; these allow the plates to be linked in series or the holes can be staggered and the plates bolted together. In areas of high shear and/or currents, additional weight may be added.