This paper describes the capabilities and technical specifications of
a pair of high-frequency acoustics platforms, known as Susy and SeaSca
n, designed to probe oceanic near-surface processes. These self-contai
ned drifters employ six upward-looking conical beam sonars (29-397 kHz
), two 360-degrees steerable sidescans (103 kHz), and several hydropho
nes. Both backscattered intensity and Doppler velocity are measured wi
th the sonars and sidescans. A detailed description of the mechanical
and electronic components is provided. Examples of sonar and sidescan
data products from these platforms are shown, including near-surface v
ertical and horizontal micro-bubble distributions, and Doppler velocit
ies due to waves.