Originally Posted by Baby Lee
Have you researched Sonosub?
They make them professionally manufacture them now, but the starters of the company made Subs with Sonotube [the form for concrete footings] and wood endcaps, sub on one end and port at the other, then feet facing down one the sub endcap.
Can be sized however you want, gussied up howe3ver you want, and tube design ameliorates need for bracing.
Is that a sub bigger than a water heater or just perspective?...