Hardware

The ADRIFT project uses drifting acoustic buoys that are composed of a deep hydrophone array (cable with two hydrophones, recorder, depth sensor, and weight at bottom), a weighted High Flyer pole buoy (containing a satellite geo-locator and a radar reflector), and a floating line/surface float to facilitate retrieval. The hydrophone array and High Flyer are connected by ~ 100m ¼” line with two hard trawl floats (one at the surface, and a subsurface float at depth), a dampener plate with bungees and a drogue (at depth).

Diagram of drifting acoustic buoy

Surface Buoy

The purpose of the surface buoy is to help track, find, and support the drifting recorder. For the Adrift survey, we used a high-flyer style of pole buoy with satellite trackers mounted on the pole and the array is suspended below.

Important

Note: A robust spar buoy developed at PIFSC was implemented as part of the CALCURCEAS survey in 2024.

Satellite Tracking

Satellite trackers are mounted to the surface buoy, and allow for tracking, retrieving, and plotting of movement for analysis.

Subsurface Components

The subsurface components include the ‘backbone’, hydrophone array, recorder, depth sensor, and anchor. The subsurface gear (minus the anchor) are typically stored in a large, red tote.