I built a 4 gun rack for my boat that mounted the guns vertically along the gunnel, hand grips towards the center of the boat. It should adapt to any size gun. Starboard should work fine and you need a router with a starboard bit. The base is a block about 1 inch thick, routed out to fit the butt ends of the guns you expect to be using. It doesn't have to fit real tight. you make a separate piece, a retaining block, to mount as high on the side of the boat as reasonable, parralell to the base. Route out cut-outs to fit the barrels of the guns, plus about 3/4 inch on the outer edge of the starboard and about 1/2 in. wider than the gun slots. This outer slot is filled with a starboard block that is secured with a screw on one side. It swivels up and out of the way to remove a gun. In the down position it prevents the gun from falling out. When the gates are down, everything is flush across the front of the retaining block. Make sure you leave some material on the retaining block to keep the swivel block from falling below horizontal. For someone skilled with a router, this is dirt simple, for me it took some time, but makes a great rack, best I ever used. My boat at the time was twenty foot and we fished in some pretty rough weather. If you are in a similar situation, make sure the retaining block fits the guns snugly. The only worry on this type of rack depends on placement and the height of the guns, sharp spear tips may get the unwary.