I do hope your spelling in your thesis is better than the title of this thread - The expression is "wet sail"
meaning to struggle in to port with wet canvas sails, little wind and at a slow speed. Not selling something in the rain.
Although reading one of my sons friends draft thesis I worked out after 3 pages that the entire thesis was a mechanical engineering essay expounding on the use of the wrong sized screws, nuts and bolts for antenna installations on domestic houses.
300 pages boiled down to "Use the right fasteners or the antenna will fall down" BTW it was accepted at the first reading.