the success of HMA No. 9, further ships were ordered by the
Admiralty. Along with the Vickers Company, three new contractors
were required to produce rigid ships. The Vickers Company had
already proven themselves with the design and construction of
No. 9 and were the only company with any experience of building
a large ship.
the trials and design success of HMA No. 9, it was agreed that
the Zeppelin threat had to be tackled head on; the Admiralty required
more ships. There were initial problems at the Admiralty with
regards to change of staff and also general opinion regarding
rigid airships, as the successful non-rigid programme was expanding
rapidly. However in June of 1915, along with the Vickers Company,
three new contractors were selected to produce rigid ships.
three new contractors were Beardmore, Armstrong and Whitworth
and finally Shorts Brothers. All three companies were to become
famous in the world of aviation. By October 1915 the drawings
were approved and three ships were ordered. By December the pace
of design and the requirement for big ships had increased dramatically
and a further sixteen ships had been budgeted for by the Admiralty.
All of these ships were to become known as the 23 Class, which
were in effect stretched versions of the original No. 9.
The designs were seen in essence as modified versions of No.9,
with an extra bay inserted in the middle of the ship. A gun platform
was added to the top of the ship designed to take a two pound
gun and two Lewis machine guns. The platform was surrounded by
18 inch sanctions carrying lifelines. These sanctions could be
extended to double the height in order to carry a canvas windscreen.
Three other Lewis guns were to be fitted at the extreme tail,
in the control car further aft and on the top walking way.
bomb load was to be greater than that of HMA 9 but none was actually
specified. The ships each possessed an external keel, to the same
pattern as the No. 9. The cabin being 45 feet long contain crew
accommodation, a wireless room and a bomb room. From the keel
further aft were three gondolas which were suspended below and
accessible by open ladders. The ship gondolas also contained airtight
buoyancy bags in case the ships had to alight on water. This was
a technical requirement of all ships since HMA 1 - the Mayfly.
With this rapid expansion of the requirement for airship production,
there were a few problems in that so far, only one company had
actually built a ship and hence had all the facilities.
April 1916 the Government approved for a total fleet of 10, 23
class ships, but this was later modified in the light of further
design technology available from Germany. The later ships becoming
the R23X class and the R31 class.
HMA 23 was the first to be completed, and hence the designation
of the class of ships. There were a number of delays in the initial
constructions and the ship was completed on 26th August 1917.
Five weeks later the HMA 25 was completed and her tests gave almost
identical results. Although not unexpected, the figures were disappointing
and 2 weeks later on the 18th October the Admiralty decided that
the design must be altered.
of these modifications had already been carried out on the first
three ships, while others followed in due course. Together they
effected a marked, if not substantial, improvement to the airships'
performance. No 25 was delivered in the same month.
25 had been assembled slightly differently from the other three
ships and always suffered from gasbag surging, which caused instability
by moving the centre of lift unpredictably. In spite of this she
flew 221 hours and 5 minutes in service, covering 5,909 miles.
Stationed for most of her career at Cranwell, she was used mainly
for training before being deleted in September 1919.