Telemetering environmental monitoring buoy and mooring

A buoy/mooring designed to measure waves with a surface-following buoy was instrumented with an ADCP and water property sensors. Compliant elastic elements at the top of the mooring allow the buoy to move freely with the waves without having to accelerate the mooring and heavy instrumentation. About 710 N (160 lbf.) of midwater flotation at the bottom of the elastic elements help keep the lower part of the mooring taut. The elastic elements provided about 1.3 kN (300 lbf.) of mooring pretension, and, depending on the horizontal current and the wave activity, the tension at the buoy could rise to about 3.5 kN (800 lbf.). Computer modeling of the mooring showed no vertical and minimal horizontal motion in the lower part of the mooring and reasonable tensions that would allow the buoy to follow the waves. Data from the accelerometer in the buoy (telemetered to shore in real-time), the SeaCats in-line and ADCP near the bottom were of high quality. The mooring was recovered by releasing a float from mid-depth that brought a line to the surface from below the elastic elements to allow the mooring (with sensors) and anchor to be retrieved. Validation of the accelerometer wave observations with a near-surface moored waves ADCP showed good agreement and indicates that the waves ADCP technology may be used for deeper water waves observations from subsurface moorings.