Pipes:
I'll concede "immateriality" to the waterline in more ways than just the lack of correspondance with the Load Water Line of a ship. Only a "line" on paper and still only a 2D plane once you understand that it references a section or slice thru a 3D object. Nothing particularly sacred about waterlines. Anyone who's fiddled with lift models knows you can slice up a model (or carve it out of stacked "lifts") on buttlines (vertical planes represented by lines parallel to the plan centerline) or on stations (vertical planes represented by lines transverse to the plan centerline). I worked on a few dozen "green" aircraft in the 70s and 80s, including a lot of Grumman Gulfstreams, Lockheed Jetstars, couple of old BAC-111s, small Canadian and Israeli jets. Every print I ever saw and every interior installation made just as much use of buttlines and stations as it did of waterlines. Hard to find your way around in one dimension!
jack
