An add on to cotton screwing. As it turns out, further research has been now leaning towards white sailors (see Doerflinger) did most of the cotton screwing (with Jack Screws) than did the black freeman or slave, during the colder months. If the cotton in the hold got wet & it would then swell, there has been loss of lives & ships due to the swelling causing the seams to open on the planking & decking. Barry