Autonomous Recorders - HARP
|Seafloor Instrument Frames
The seafloor instrument frames developed and used by our group are compact arrangements of flotation, data recording electronics, batteries, ballast and release systems which free-fall to the seafloor, record sound for a specified period, and are recalled back to the sea surface for data retrieval and battery replenishment. Seafloor packages are easy to deploy and recover from typical oceanographic ships and mid-sized fishing vessels. In all configurations listed, the hydrophone sensor was designed to be tethered 10m above the seafloor package which provides a quieter acoustic background for better sound recordings than near the sea surface.
Instrumented moorings can be very large with many different components spread vertically along a line, wire rope or chain. Moorings can be configured with large amounts of flotation and ballast providing protection from fishing operations and heavy weather/currents but require vessels with heavy lifting capabilities. They can be minimized so as to make handling of individual components (flotation, data recording electronics, batteries, ballast and release system) possible from a small boat.
|Credit: Sean Wiggins|