A portable retractable ADCP boom-mount for small boats

This paper describes the design, testing, and application of a portable and retractable shipboard acoustic Doppler current profiler (ADCP) boom-mount. The boom is specifically adapted for small fiberglass boats working with a minimal crew. The design permits the rapid collection of ADCP data on disc ontinuous transects which would be difficult or impossible using a large di splacement hull vessel or with a towed vehicle. This capability is particul arly useful in shallow wind-driven estuaries and in tidal channels where fl ow time scales are often on the order of several hours. Tests of the boom s how that high quality ADCP data (as measured by percent good) can be obtain ed at boat speeds up to 4.0 m s(-1) and that data quality depends on transd ucer depth. The utility of the retractable design is demonstrated with an 8 m boat on two nearly synoptic ADCP surveys of a shallow estuary. With mino r modifications to accommodate different vessel geometries, the design coul d be readily adapted for use on similar vessels.