I have a 16' Invader I/O runabout with wrap around seat backs for the rear seats on both sides of the I/O motor cover. My problem is how to remove them. The bolt and screw on the back of the seatback is available by reaching in to a rear cavity and unscrewing the nut. However, I can find no access to remove the seatback where it wraps around and is against the gunnel side of the boat. <br /><br />I'm sure that I'm not the only one who has run into this so Please Help. How do I remove the seatbacks so that I can reupholster them