As a former Machinist Model Maker in the AeroSpace industry we normally worked from a "WaterLine" when building fuselages. The fact that our models were designed to go through the "Air" rather than "Water" was of no consequence.
As has been shown the term Water Table has been in use for well over a century & will likely be around as long as Break Open double guns exist, so again I say it is utterly useless to raise a Fuss every time the term is used. As to whether or not it is correct may be like a lot of other terms, "Depends" are you talking to a "Limey" or a "Yank".
