Well I could not really find anything on how best to close the mast gate and did not much like the idea of using a pin to keep them from sliding out so I made my own out of a few pieces of aluminum and some 1/4 bolts. I carefully cut one piece to fit precisely inside the whole using round head bolts with the heads on the inside to avoid them catching the slugs as they pass, and then another larger piece curved to fit the mast and tap two 1/4" bolts to hold it in place. You can take one bolt off and just loosen the other so the door will swing clear, put your sail in and close it up and you are good to go for the day.