ADCP Mooring Deployments
Centre for Earth and Ocean Research
University of Victoria
Click on images for a larger version.
UVic owns two RDI 300 kHz ADCPs and deploys them mounted in gimbled bottom brackets. Shown above is a deployment and the two ADCPs. The center picture is the gimbled standard Workhorse ADCP, while the picture on the right is a special vertical beam 300 kHz ADCP. After trying various configurations, we're converged on a rather simple but functional mooring that has now been deployed over 20 times in water ranging from 50 to 130m deep. The 300 kHz ADCP can "see" about 100m, with up to 128 bins, of 0.5 to 4 m size. We have 170 MB of RAM so, as many as 100000 ensembles can be recorded. Here are some pictures and links to a couple of images and postscript files that show the moorings being deployed and how they sit on the bottom. Click on the pictures to get a large version of the picture.
The latest Aluminum bottom bracket design figure is in this PDF file, and the deployed mooring looks sort of like this PDF figure when it sits on the bottom (we now use large single floats). We deploy it by lowing the "release" mooring part with the ground line (see picture to the left). The 200m ground line sits along the bottom and is a back-up drag line if the accoustic release fails. The instrument and bottom bracket are then deployed from the work winch with an acoustic release (right). The ground line is kept taut and the bracket is lowered to the bottom. The deployment release is triggered when the bracket lands. The single red float brings the release up off the instrument after deployment.
Recovery is basically the reverse. We pop the moored acoustic release, which brings up the yellow float and end of the ground line. We then winch up the ground line and recover the bottom bracket and instrument (below). Deployment takes from 1 to 2 hours, and recovery is about an hour. UVic does not have anchors or mooring acoustic releases, but we do have the deployment release.