Light weight trailer walls with smooth surfaces

A trailer having a frame supported by at least one axle assembly;

• a least one bottom rail attached to the frame;
• at least one top rail supported by the frame;
• and a plurality of vertical panels secured to said at least one bottom rail and to said at least one top rail;
• each of said panels comprising an inside wall, an outside wall parallel to and spaced from the inside wall, a first vertical end wall integral with a first side of the inside wall and the outside wall, a second vertical end wall integral with a second side of the inside wall and the outside wall;
• a first outside flange integral with the first vertical end wall and having an outside surface in a common plane with an outside surface of the outside wall, a second inside flange integral with the second vertical end wall and having an inside surface in a common plane with an inside surface of the inside wall, a first inside flange integral with the first end wall and having an inside surface in a vertical plane that is parallel to and spaced from an inside vertical plane containing the inside surface of the inside wall, a second outside flange integral with the second end wall and having an outside surface in a vertical plane that is parallel to and spaced from an outside vertical plane containing the outside surface of the outside wall, and wherein the space between the first outside flange and the first inside flange exceeds the thickness of the first inside flange in a direction transverse to the inside and outside vertical planes, and wherein the space between the second outside flange and the second inside flange exceeds the thickness of the second outside flange in the direction transverse to the inside and outside vertical planes.