A buddy of mine converted one of those to a stew pot.
Plumb the jacket with water lines, routed up high, so that you can have an "expansion" tank considerably higher than the level in the jacket.
He used an old water type fire extinguisher for the "expansion" tank, vented to the atmosphere, with a water level sight glass added.
He sold Brunswick Stew, and cooked 60 gallons at the time.
He placed 2 medium sized propane burners under the bottom, firing directly on the outer skin of the water jacket.