Each car was divided into two parts by a bulkhead, the forward
portion being the control compartment in which were disposed
all instruments, valve and ballast controls, and all the steering
and elevating arrangements. Engine-room telegraphs, voice pipes
and telephones were fitted up for communication from one part
of the ship to the other. The keel could be reached by a ladder
from each car, thus providing with the climbing shaft through the
hull access to all parts of the ship.

The original engine equipment of No. 9 was composed of four
Wolseley-Maybach engines of 180 horse-power each, two being
installed in the forward car and two in the after car. As the
ship was deficient in lift after the initial flight trials had
been carried out, it was decided to remove the two engines from
the after car and replace them with a single engine of 250
horse-power; secondly, to remove the swivelling propeller gear
from the after car and substitute one directly-driven propeller
astern of the car. This as anticipated reduced the weight very
considerably and in no way lessened the speed of the ship.

The forward engines drove two four-bladed swivelling propellers
through gear boxes and transmission shafts, the whole system
being somewhat complicated, and was opposed to the Zeppelin
practice at the time which employed fixed propellers.

The after engine drove a large two-bladed propeller direct off
the main shaft.

The petrol and water ballast were carried in tanks situated in