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
Following 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.
The 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.
The 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.
In 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
The 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.
Some 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.
No 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.