Thanks, Jay. Flotec is a partner with Teledyne/RDI and sells a variety of ADCP deployment products including the buoys made for their ADCPs. http://www.flotec.com/flo4.html
Here's another article that sheds some more light on their use: http://www.rdinstruments.com/pdfs/Anderson.pdf I. INTRODUCTION Strong ocean currents can disrupt various deepwater activities and cause downtime for hydrocarbon exploration and production activities. Thus, accurate and timely observations can help with planning and assuring safe operations. Remote sensing cannot always be counted on to provide timely observations of the sea surface and is not a direct measurement of ocean currents. Drifting buoys have proven to be a cost effective means of collecting ocean current observations; however, drifters report only near surface currents and the Lagrangian technique does not provide a means of activity targeting and monitoring a specific site or area. Acoustic Doppler current profilers (ADCP) mounted on moorings and platforms can provide real-time current information but are not always optimally located. ADCPs deployed on ships provide the most viable way to survey ocean current profiles. Only a shipboard ADCP can be used to collect ocean profiles while underway and thus provide surveys of synoptic ocean features. Deepwater current profiling requires a low-frequency ADCP operating at 38 or 75 kHz. Traditionally these large systems have been hull mounted systems mostly deployed on research vessels. When care is taken, the hull mounted system operates in a low-noise, bubble free environment and provides optimal performance. However, the system is tied to a single vessel. In this paper, we report on the development and performance of a towed body with a 75 kHz ADCP. This application provides a system that can be easily relocated and deployed for various vessels, yet provides a very quiet, stable platform for the ADCP.