My goal in designing the pro tunnel was a hull that generates maximum aerodynamic lift in a boat meeting the gt pro weight requirement of at least 650 lbs. (boat.  8′ puddle duck racer one design racing sailboat based on bolger brick. developmental class, defined hull, unlimited sail rig and underwater fins.. View tunnel hull boat plans for the seabright 21, a shallow draft, atkins style tunnel boat. see our plywood version of this tunnel boat design at bateau!.