the vertical distance measured amidships from the keel line to the top of the freeboard deck beam at side. In wood and composite ships the distance is measured from the lower edge of the keel rabbet. Where the form at the lower part of the midship section is of a hollow character, or where thick garboards are fitted, the distance is measured from the point where the line of the flat of the bottom continued inwards cuts the side of the keel., the depth of a ship from the top of the keel to the top of the beam at side, measured at midlength; referred to as Lloyd's D