In a nonrigid airship this is accomplished by incorporating separate, smaller envelopes called ballonets within the main envelope.
An airship that is going to take off at sea level and climb to 10,000 feet en route must have approximately 30 percent of its total envelope volume taken by air in the ballonets at take off to allow room for the expansion of helium during the climb.
Eaton has been selected to design, develop and integrate the hydraulic power generation system to power the blowers for the ballonets
of the lighter-than-air gas management system, the winches for the cargo loading system and the flight controls.
The rigger climbs about in the framework, testing his ballonets and making sure that the ventilators are working properly and letting out the gas forced from the ship in its continual ride.
The observation officer climbs into the interior of the ship, there the rigger is diligently searching all over the ballonets, looking to see whether or not gas is escaping anywhere as a result of damage done by shots.
Hydrogen gas fills internal ballonets
, providing the lift necessary to keep the massive craft airborne.