Recently had two stanchions repaired. There is a stud in the center of the stanchion that is bolted through the deck. The nut can be seen from inside. Depending on which stanchion , you may have to remove some covers to find it. Warren & Pattie Updike C320, #62, 1994, "Warr De Mar" Frog Mortar Creek, Middle River Chesapeake Bay