Arctic Winch

The Arctic Winch is a small buoyant float (white) attached to the mooring’s red top-float. It carries instruments to measure temperature, pressure, and salinity of waters near the ice-infested surface. On regular intervals, the winch is released and allowed to rise on a tether either to the ocean surface (when no ice is present) or to the underside of the ice. The float’s pressure sensor detects the rising motion, so if the float bumps against the underside of an ice floe, the sensor triggers a winch on the mooring’s top-float, and the small float is immediately reeled back down to the subsurface mooring, where it can remain out of harm’s way of ice until the next cycle. Meanwhile, another instrument called a moored profiler (yellow) moves up and down the mooring line, collecting data on waters at deeper depths. (Animation by Jack Cook, Woods Hole Oceanographic Institution)