The knuckle is an area of the SW Ledge roughly 25nm SW of Destin.. 220 I believe is a close heading. It is an area just where the ledge bends to the north then back around to the south heading out towards the nipple. I dont have mapping software but if u pm me I will dig out some coordinates for the area. There is usually at least one shrimper out there this time of year and its known for blackfin tuna for that reason. Hope this helps.