Last winter I was looking for a way to add a rear casting brace to my Wood River Boat Works 17x54. I came up with this using left over meranti I bought to add a storage box under the front seat. It's essentially a 4 inch deep rectangular box that fastens down over the original (Tatman style, is that correct??) rear seat. This moves the rear angler/passenger's weight forward 9 inches which may improve handling. The box is open storage behind the seat back. The front portion of the actual seat surface lifts up to offer a little covered storage. I used a pair of classic wooden "horns" patterned on the front brace. This configuration avoids a pedestal or an arch that would separate the rear passenger from the rest of the boat. The mandatory beverage holder is a shelf on the back side of the brace so a container is less likely, I hope, to interfere with line. It's fairly stable simply screwed down to the frame under the existing seat planks, but to distribute weight a bolt at each gunnel clamps each end of the plank that the knee braces are mounted to. It's rock solid that way but I figure if the boat has to flex, it will slip or give if the bolts are not over tightened. It will end up scuffing the gunnels, and there are 8 new screw holes hidden between the various existing seat planks. Otherwise, I did not have to modify the existing boat at all. Standing in the boat, I can brace the shin and knee against the horn if I step forward with my aft leg. Alternately, I brace my upper calf against the horn behind me if I step backwards with my aft leg. All it needs now are several coats of spar varnish. Looking forward to seeing how this works out this spring.