Which implies the tank has mass that is added to the tonnage of the ship while still attached to the ship.A ship’s Thrust must be recalculated when carrying
a drop tank, using the combined tonnage of the ship
and the drop tanks it carries.
As for the jump.
Sounds like the energy dump.To jump, a ship creates
a bubble of hyperspace by means of injecting highenergy
exotic particles into an artificial singularity.
Which sounds like after the energy is used to create the pocket universe the hydrogen is used to expand the bubble by being injected into the pocket.The singularity is driven out of our universe, creating
a tiny parallel universe which is then blown up like a
balloon by injecting hydrogen into it.