Mooring
Mast Technical Information
Testing, Construction and Designs
The design concept
for mooring airships without the need for a ground crew
came from the original concept of the "three wire
system". Experiments were carried out by the ability
to moor airships from three wires from the bow of the
ship, then the ship "flown"with the wires taught.
This proved that airships need not be housed in the hangers,
of which the Germans had proved was the time when the
ships were most vaunrable.
The first high mast was developed in Pulham where a mast
erected and an airship was able to dock, the crew could
alight the ship, and also be refuelled and ballasted at
the same time. The advantages of a high mast was that
an airship could be moored both day and night, along with
the fact that a craft could take up moorings in windspeeds
of up to 35 knots.
The first mast was
a lattice mast constructed by Vickers, with the intention
that it should be erected at Barrow-in-Furness, but in
May 1918, the decision was made to errect it at Pulham.
The Vickers mast was a comparatively short tower, 120ft
high, was capped by a mooring attachment which allowed
the moored craft to swing through a full 360 degrees so
that it would face the wind at all times. A fundamental
advantage of the new system was that only a dozen or so
men were needed to secure the craft, instead of the large
ground handling party required earlier. This was of particular
importance during a period of austerity and financial
restrictions.
Vickers
Prototype Mast
As the new mast was
deemed a prototype, it had no lift to enable the ship's
crew or passengers to reach the top in comfort. Insread
they had to climb the many steps up the outside of the
tower to reach the rotating cap at the top. Entry to the
ship was gained by means of a circular platform encircling
the cap, from which one clambered up through a hatch in
the nose of the ship
HMA No.24, the second
ship of the 23 Class, was flown from Howden to Pulham
on 31st May, 1918, with the intention that she would be
used for mast mooring trials, but is was not until March
1919, that the mast was setup at Pulham. No. 24 was fittted
with a modified nose cone, a bow coupling which and additional
ballast tanks, and her midship gondola was removed before
trials could begin.
The No.24 was moored at the mast for the first time on
11th June, remaining on the mast until 30th June. The
ship was taken from the mast for inspection and minor
modifications, but was back on the mast from 1st September
to 15th October, and again from 7th November until mid
December. In these experiments the mooring cable was attached
to the mast whist the ship was on the gound, and no "yaw
guys" were used to steady the ships nose, as she
approached the masthead. Two men remained on duty in the
control car and one below during her sojourn on the mast,
so that water ballast could be taken aboard by hose if
she became light, and began to ride up. Gas could be fed
in if she became to heavy for a discharge of ballast to
be beneficial. During the ships total of sixty-two days
on the mast, in all weathers the ship coped with wind
speeds of 45mph without trouble.
Whilst at Pulham,
No.24 tested a system involving the use of ropes to guide
the ship down; this was not found to be satisfactory,
though it did lead to the development of a more functional
system some time later. H.M.A No.24 was deleted before
the end of the year, and it was left to the R.33 and R.36
to carry on the mooring trials at Pulham.
The revolving masthead was later fitted with an attachment
designed at Cardington. Named the Bedford-Pulham mooring
attachment, it comprised an elaborate arrangement of cables
intended to facilitate the linking of an airship to the
tower. One ran from a winch at the base of the tower,
through an attachment at the top and then out at a downward
angle to another attachment set in a large concrete square
on the airfield some distance from the tower. At this
end was a quick-coupling device.
Airships equipped to user this morring arrangement carried
a similar cable and coupling attachment in their bow section.
To moor, the airship slowly approached the concrete square
at a low altitude and in line with the cable running up
to the top of the tower. The airships's cable and coupling
attachment was lowered and a member of the gound crew,
positioned adjacent to the concrete square and lower attachment,
prepared to receive the cable. Great caution had to be
exercised at this juncture as the airships passage through
the air had generated considerable static electricity,
which would earth itself as soon as the cable was close
to the ground. To save himself from a almost fatal shock,
the ground crew member had to ensure that hte cable had
touched the ground before he attempted to retrieve it.
When all was safe, the airships cable was attached to
the ground cable and the cable would be gradually wound
up towards the top of the tower. Eventually the nose of
the airship reached the mooring attachement on the tower
to and fastened securely to the tower. As the top of the
tower revolved, it allowed the airship to ride into the
wind, or weathercock, in airship terminology. Advanages
of this system was that a craft could thake up moorings
in wind speeds up to 35 knots.
The new mast was used a great deal and over serveral months
some fifty successful moorings were made by the R.33 under
the supervision of Captain Williams, this involved some
171 hours of flying. On surprising fact which emerged
from these trials was that the craft could be brought
up to the mast and attached in very bad weather conditions.
One report stated that the R.33 was successfully moored
when the wind was gusting at 80mph. The R.33's stint on
the Pulham mast proved that the design was sound and efficient,
and that a great step forward had been taken in ground
handling of airships. Many local residents recall the
impressive sight of the R.33 siding the mast at night,
with floodlights shining on her silver-coated hull; the
lights on board gave the impression of an ociean linder
lying in dock.
During her many days
on the mast, the R.33 proved neither rain nor dry snow
posed a problem, but following the destruction of R.26,
it was recognised that wet snow certainly did. Captain
F.M Thomas at Pulham devised a snow clearing gear which
consisted of an endless wire atop the ship between frames
7 and 34, which dragged lenghts of 2.5 inch hemp rope
fore and aft along the ships cover, to clear the snow
which had accumilated on the top of the hull.
On 3rd June, 1921, a heavy rain squall forced the tail
of the ship to the ground, despite a release of ballast.
It was thought to be the dynamic pressure of the raindrops
rather than the their actual weight that did this. Fortunately,
the tail fin was submerged in a pond, and on that occassion,
the airship escaped damage.
The Pulham mast was
used for a number of years by many of the ships stationed
there. All British rigid airships were fitted with bow
mooring gear and crew/ passenger access. Later development
of the mast lead to a higher mast of some 200ft, which
also contained a lift for easier access for crews, passengers
and goods.
The nose entrance
design was incorporated in to the R33, R36 as well as
the standard moring design of the R100 and R101. With
the later loss of the R101, the Government proposed the
use of or leasing of the masts and sheds to the Zeppelin
company. It was noted that the Graf Zeppelin and later
Hindengburg designs would have had to be altered to incorporate
the access via the nose of the ship.
Mast
Specifications
Height
202ft
Diameter
at base
70ft
View
the mast in operation - click on the movie clip above
Photo
Gallery
R33
on the first high mast design for an airship
Close
up of the nose of the R.33 attached to the Vickers Mooring
mast at Pulham, and crew entering the ship 24th March 1921..
The 360 degree platform can be seen, and small nose hatch
for the crew.
A
view from the R33 towards the Pulham Mast
The
Mast plans for the Standard High Mast
A
plan of the masthead and entry to the Airship
The
mooring schematic for the proposal of mooring large airships
against high masts.
Artist
impression showing the masthead and connection machinery
in place.
Mooring
an Airship
The following is a description
of how the mooring of an airship would be undertaken, this
was from an article written in the Times from August 1920
when a ship would be moored to the Pulham mast, which was
a smaller mast with no elevator
Every time an airship sets
out on a voyage an army of men has to be employed to help
get her away, with the aid of guide ropes. The voyage over,
the berthing of the vessel again involves guide-rope control
from the ground. Before long, however, these primitive methods
may be replaced.
The problem has been tackled by Messrs Vickers, Limited,
at their Barrow Works. Steel towers are being constructed
there from which it will be possible to supply airships
moored to them with fuel, water, gas, and goods; and crew
and passengers also will be able to go aboard from the towers.
The
completed mooring tower will be about 150ft high, built
of steel lattice-work and furnished with a revolving head.
To this the airship will be closely moored, bow on, and
floating clear of the ground the vessel will be able to
swing round with the direction of the wind, the necessary
protection from which is provided by the stream-line shape
of the body. A winch and cable will bring the airship to
the tower-head, and a lift working inside the tower will
carry crew and passengers, fuel, stores, cargo, and so forth,
to the airship.
At
the top of the tower a small compartment will serve as an
ante-room to the airship, connected by a flexible enclosed
gangway. An airship making for the tower will send out a
wireless message announcing her intention. From the tower
head a wire cable will be dropped to the ground and there
picked up by a man who will enter a small car and drive
away some 300 yards. A second cable, weighted with sandbags,
will be dropped from the airship when a ground signal has
indicated the point at which it will be picked up, and the
two cables will be coupled.
The airship will then be hauled in, assisting where necessary
with her own power, and when she has been moored it will
be possible to uncouple the cables and re-wind them. The
airship will be released automatically from the mooring
tower by a mechanism controlled by one man, so that from
first to last, apart from those on board, not more than
three men will be needed to bring a dirigible to port and
send her out again. Some of these towers will be completed
shortly and supplied to aerodromes without delay. At the
foot of the tower waiting-rooms will be built, which in
the future might be developed into hotels.
Construction
The
huge airship mast was constructed for the civil programme
in 1926, built by the Cleveland Bridge and Engineering Company
under the direction of Major General Sir William Liddell,
Director of Works and and Buildings at the Air Ministry.
The Cardington Mast was completed in 1926. The Cardington
and Ismalia masts were both up to the level of the searchlight
gallery to the tower were an open work structure made up
of eight main legs set in concrete bases and cross braced
on all eight faces to horizontal frames arranged at intervals
of 28ft 4 inches.
From
the searchlight gallery upwards the surmounting tapered
circular turret was framed in steel, endoused with corrugated
sheeting and lt by sixteen windows. The top platform, at
a height of 170ft, from wich the passengers embarked and
disembarked in to the airships, was 40 ft in diameter and
encircled by a heavy parapet. The top rail of this parapet
formed a track on whic a gangway, left down from the ship,
ran on wheels to give freedom for the airship to move around
the top of the tower as it swung in the wind.
A lift shaft, 9ft 6inches, ran up the centre of the tower
in a separate block, with a stairway around the outside.
The electric passenger lift, with capacity for 12 persons
at a time, ascended to a height of 156ft from the ground
at which level there was a steel platform with stairs up
the remaining 14 ft to the passenger platform.
The
very first stages of the Cardington Mast construction early
1924
The
basde of the mast under construction at Cardington,1924.
Part of the mooring head machinery is about to be winched
up the central stairwell.
The
mast nearing completion, here without the mast head housing
The
mast almost completed and winch buildings being added.
The
mast head constructed showing the nose docking arm fully
extended
Inside
the mast head, showing the suspension mechanism for the
docking arm and the extendible arm retracted. It was maneouvered
on the pulleys attached to it's lower end.
In
this photo of a visit by MP's, the mast head controls can
be clearly seen.
The
Missing Masthead
Babcock and Wilcox Ltd
were the main contractors for the mast head machinery. They
had already produced the mooring machinery for the Cardington,
Ismaila and Karachi masts . The second sets of orders were
already being placed and the Montreal and South Africa masts
were ordered at the same time and it is noted that Babcock
and Wilcox gave a 2% discount on the mast head prices due
the "bulk" order. The Montreal mast was completed first as
it was the Montreal trip was which deemed to be one of the
primary trips for the demonstration flights of the new airships.
This was delivered to Montreal in August 1928 and so it is
expected that, at that time, the South African mast heard
would have been completed after this date, maybe early 1929.
Whatever happened to the South African masthead was unknown
but however years later a comment was made to a member of
the AHT stating that when posted in Aden during the second
world war, a "airship masthead was seen in storage". How true
this is, we cannot confirm, however it would tie in with the
fact that the Canadian mast had to be constructed first as
it was always agreed as part of the "demonstration" flights
of the 1924 Airship Programme. Therefore if the first masthead
was constructed and delivered in 1928 then the second mast
head would have been constructed and also forwarded for onward
delivery to South Africa. Aden is a key port for trade on
the west coast of Africa. On the 1926 proposal map, both Cape
Town and Durban are noted, however on a later edition map,
presumed to be end of 1930 shows both Durban and Cape Town
to be proposed Airship bases with masts and sheds facilities.
Testing
the Mast
Once
the mast had been completed, the testing of the design was
needed. A strain test to 30 tons was ordered and undertaken
by a pulley system to test the strength of the mast tower
and mooring machinery
The
wires were connected from the top of the mast to a steam
winch and pulley system on the ground
The
team assembled on the ground
The
pulley connection to the steam winch.
The
connection at the top of the mast, and with no health and
safety, the technician is checking the loading guages at
the top of the mast.
A
member of the team measuring the tension on the wire
Mast
Variations
This later design became the template for all masts constructed
for the Imperial Airship scheme and masts were constructed
of the type in Cardington, Ismailia in Egypt, Montreal in
Canada and Karachi in India, each one adding to the success
of the desing. Interestingly each mast design was altered
for example buildings added in to the base of the mast in
Montreal and Karachi designs.
The
Ismalia mast was a virtual copy of the Cardington mast layout
The
Karachi mast had buildings incorporated in to the base of
the mast, but an exposed lift shaft
The
Montreal mast had buildings in a classical "Regency"
influenced design at the base and enclosed lift shaft. The
mast top was painted orange and silver to make spotting
the mooring easier to the pilots
The
R100 was the only airship to use the Monreal mast.
Mooring
Masts In Use
The success of the
earlier mooring trials with the R 33, meant that the new high
mast and mooring gear would be used for future airships. The
R33, R34, R36 were fitted with a boarding "hatch"
in the nose, whilst later ships incorporated the design during
construction and the R38, R100, and R101 were all fitted with
a retractable doorway for easier access. This meant that the
masts could be used by multiple ships, and became a standard
feature in British airship design.
The
first ship to use the newly completed mast was the R 33,
which can be seen here moored to the mast.
The
R101 soon followed in 1929
The
R100 also moored to the Cardington mast, here showing her
original configuration just after her first flight from
Howden construction facility, to Cardington.
The
close up on the nose and the access to the ship.
Close
up of the mast head. Also can be seen are the searchlight
emplacements and the gas hoses for topping up the gas in
the ship via the nose.
Decomissioning
of the Mast
A remaining
strut of the Cardington Mooring mast - part of the AHT collection
The Cardington mast
remained a prominent feature of the local area some 13
years after the last airship docked to it, and was decomissioned
in 1943 and sold for scrap. The original concrete base
still remains to this day, along with the power house.
As late as 1983 the pile of clapboard buildings could
still be seen, which had once performed the historic role
of Customs Office for passengers travelling abroad by
airship. The Customs House was only used on three occasions,
for the R100's out and return flight, and the R101's departure
to Karachi, in 1930.
As part of the AHT
Collection and Archive, a girder piece was presented to
the Trust by Mr John Benson, who as a child from the age
of 2, lived in one of the wooden buildings which was designed
as originally been provided as accommodation for the Airship
crew. He live on the mooring mast site for 11 years with
is mother and father. His father was employed as a cowman
by Mr Alex Simpson, farmer at Manor Farm, Cotten End,
on which land the mast site stood, who offered him and
his family the use of the buildings. Mr Benson decribes
life on the site as interesting, as they had the luxury
of a flushing toilet, coke boiler and bathroom, the power
supply had been disconnected. He remebers the building
being backing hot in the summer, and freezing in the hard
winters of the late 40's and 50's.
The mast had been
demolished before he moved in, however as a connection
to the past, the address was "The Bungalow, Mast
Road, Cotton End". One of the larger buildings which
is still standing on the site, was spruced up and decorated
by the Cotton End villagers in June 1953, and used as
a venue for a tea party to celebrate the Coronation, as
that time there was no village hall. An electric cable
was run across the fields from the farm so that the Coronation
could be watched on television.
At that times there
were many items of the removed mast laying around the
site, when the family evenutally moved from the site,
they took this girder as a souvenir.
The girder was a bracing
member of one of two in the form of a cross, and they
can be clearly seen in photo's of the mast. The girder
is exactly 6ft in length, two inches wide, and has a stamp
of JC&S Ltd.clearly marked twice on the side, with
three fastening holes drilled in to it. To our knowledge,
apart from the wooden boxes made out of the the lift carriage
for sale to benefit the Red Cross, this is the only other
surviving peice of the mooring mast.