One of the difficulties of taking CTD measurements from a sailboat is the need for stops for profiling. This time we practiced a stop under sail and also perform CTD casts when possible underway at slow speed. In sailing, heaving to is a way of slowing a sailing vessel’s forward progress, as well as fixing the helm and sail positions so that the vessel does not have to be steered. We practiced this technique with obvious success and performed profiling at a slow speed with RBRbrevioCTD.
Here is the Ruskin plot of the “free-fall” RBRbrevioCTD profiling under a speed of 2 knots with the release of 20m of the line: