RIGID AIRSHIP 23 X CLASS

During the early days of building the airships of the 23 class,
further information was obtained relating to rigid airship
construction in Germany, which caused our designers to modify
their views. It was considered a wrong policy to continue the
production of a fleet of ships the design of which was becoming
obsolete, and accordingly within ten months of placing the order
for this class a decision was reached that the last four ships
were to be altered to a modified design known as the 23 X class.
As was the case with the ships of the preceding class when
nearing completion, they were realized to be out of date, and
special efforts being required to complete the ships of the 33
class and to release building space for additional larger ships,
the construction of the second pair was abandoned.

The main modification in design was the abolition of the external
keel, and in this the later Zeppelin principles were adopted.
This secured a very considerable reduction in structural weight
with a corresponding large expansion of the effective
capabilities of the ship.

It has been seen that the purpose of the keel in No. 9 was to
provide a structure sufficiently strong to support all the main
vertical bending moments and shearing forces, and that in No. 23
this principle was somewhat different, in that the keel in this
ship was primarily intended to support the distributed weights of
petrol, water, ballast, etc., between the transverse frames.