New Knot to the Winch

Every once in a while we’ve had a profiler get stuck at the surface. In seas greater than 2-3 meters, the knot specified in the Thetis manual pulled through the winch spool, setting the profiler adrift. We worked with Sea-Bird on a new knot. It has held in 4.5 m significant wave height 25 knot wind seas.

Upgraded Antenna Cable Connector

The coaxial Fischer connectors from the antenna to the control can are not rated for the depths transited by Thetis profilers. We’ve replaced these with wet mate connectors from SubConn. These new connectors are more robust, and they have enabled our profilers to make faster connectors with our shore server.


To minimize fouling on dissolved oxygen and spectral irradiance sensors, we shine a UV light from AML Oceanographic on the sensor faces of those instruments. We confirmed with our spectral irradiance instrument vendor (Satlantic now Sea-Bird) by deploying a test unit for 6 months and having the vendor examine the sensor before and after for damage.

Anti-fouling paint

After a two-month summer deployment in shallow water, a profiler was so covered in barnacles that it sunk to the seafloor. We recovered it via ROV, and since then we’ve applied anti-fouling paint to our profilers, especially on the foam because it has so much surface area.