engine bearers in place amidships, but the design was recast to provide better aviation facilities, with the result that a number of changes were made on the slipway. The engines and boilers were moved right aft into what would have been the after hold, and the bridge structure moved as far aft as possible. The original sheer on the upper deck was removed to give a level 130ft-long flying-off deck at the bow. The forecastle with its facilities for working anchors and cables was placed under the flight deck with low headroom to minimise the space used for it.
The aircraft, spare parts and fuel carried would be considerably lighter than the original cargo in the holds, so the vessel was extensively ballasted, both to make it a steady platform in high seas and to reduce the freeboard to simplify the operation of lowering and raising seaplanes to and from the water. The forward hold and the space that would have contained the machinery amidships were transformed into a single hangar 150ft long, 45ft wide and 15ft high that was expected to be able to accommodate ten seaplanes. Two steam cranes were installed, one either side amidships, to hoist aircraft out of the hangar on to the deck for preparation, to lift them on to the water, and for the reverse processes. Each was capable of lifting 6,000lb, but Admiralty admitted that their selection was due to ready availability and electric alternatives would have been preferred. The hangar was surrounded by large cellular water tanks both to add the amount of ballast and to serve as protection against fire, since the petrol which fuelled the aircraft and especially the vapour it gave off had a low flashpoint and were known to be extremely dangerous, especially in confined spaces.
The bottom of the hangar rested on number 5 deck, the lowest continuous deck in the hull. Above the hangar, airframe, engine and component workshops were built on to number 2 deck, just below the upper deck. Access to them was through a hatches in the upper and number 2 decks, which were 42ft long and 30ft wide. Aircraft, engines or bulky stores could be lowered in or hoisted out by either steam crane or a five-ton derrick attached to a kingpost on the port side, just forward of the bridge.
Petrol was stowed in 2gal cans in a compartment forward of the workshops that was inside the water- tank barrier. Accommodation for the ship’s company and the embarked air group was better than in other contemporary warships, partly because of the hull’s mercantile origins but mainly due to the lack of guns, with their high demands for manpower to operate them and handle ammunition from the magazines. Air ordnance arrangements were well thought out, in advance of those considered in any other navy and coped well with rapid advances in the ability of naval aircraft to carry weapons. They included a bomb room, a torpedo warhead magazine, a separate torpedo body room and stowage for small-arms ammunition and grenades. There was an open area under the bridge, aft of the access hatch, in which an aircraft could be placed clear of other working areas to run up its engine or undergo maintenance.
A view forward from Ark Royal’s bridge, showing the open hangar hatch with men visible in the workshop area. Two Short seaplanes are being maintained on the forward deck. (AUTHOR’S COLLECTION)
The flight deck was the largest yet fitted in any warship when the vessel completed and, to help aircraft accelerate along it, it could be given a pronounced downward slope by flooding ballast tanks built into the bow. Unfortunately the low ship’s speed of only 11 knots meant that unless there was a considerable natural wind, which would have made ranging and spreading extremely difficult, take- off from the deck was impractical. Instead, the area was used to prepare seaplanes, which were then craned on to the sea for take-off and the subsequent landing. The higher part of the water barrier around the hangar had the effect of reducing the ship’s excessive metacentric height, with the result that rolling was less severe and aircraft swung less when being moved through the hatch and over the side. A unique feature was a mizzen mast aft, on which a sail could be hoisted to help keep the ship head to wind when operating seaplanes while it was at anchor.
Ark Royal’s well equipped workshops gave her an important capability as a mobile naval air base and she was retained in service after 1918. In 1930 she was fitted with a catapult and used initially for trials and then for training seaplane crews destined for catapult flights in battleships and cruisers. Maintained at a low state of readiness, she was used for sea trials of equipment intended to improve the operation of seaplanes, including the unsuccessful Hein Mat towed astern, intended the lessen the effect of waves.
Ark Royal seen from the air, with her steam cranes working. A canvas screen has been rigged across the hangar opening to provide shade, and the flying-off deck forward, which was never used for its intended purpose, is cluttered with boats and washing. (AUTHOR’S COLLECTION)
Re name d Pegasus, the former Ark Royal is seen here in use as a fighter catapult ship during the Second World War.
(AUTHOR’S COLLECTION)
Ark Royal technical details
Displacement: 7,450 tons deep load
Dimensions: length 366ft
beam 50ft 6in draught 18ft 6in
Machinery: 1 shaft triple-expansion
reciprocating steam engine 3 x single-ended tank boilers
3,000ihp delivering 11 knots maximum
Armament: 4 x single 12pdr; 2 single
Maxim
Protection: None
Fuel: 500 tons FFO
Endurance: 3,030 miles at 10 knots
Complement: 180
Aircraft operating data:
Flight deck: 130ft x 44ft
Hangar: 150ft x 45ft x 15ft
Catapult: 1 x 12,000lb at 55 knots fitted in 1930
Lifts: None, aircraft lifted through
40ft x 30ft hatch by crane
Aircraft: up to 10
Aircraft fuel: 4,000gal of petrol in 2gal cans
1,000gal of lubricating oil in cans
Air weapons: torpedoes, light bombs, grenades and machine-gun ammunition
Engadine, Riviera
The pressing need for ships with greater speed than Ark Royal to operate aircraft with the fleet after the outbreak of war in August 1914 led to these two ships being requisitioned from the South Eastern and Chatham Railway Company on 11 August 1914. Both were well known for providing a regular, fast passenger service between Dover, Folkestone and the French Channel ports. They were fitted out in Chatham Dockyard with temporary arrangements including hangars sited forward and aft which had wooden decks surrounded by canvas screens and covered by canvas awnings. There was no flying deck, and seaplanes were winched on to and off the water by derricks worked by the vessels’
capstans. They were smaller than Ark Royal but, at 22.5 knots, considerably faster and able to keep up with the battle fleet, although, since their boilers were coal fired, maximum speed depended on the quality of the coal, the number of stokers and their ability to keep the fires at peak thermal efficiency;
it could only be maintained in short bursts. Their weakness was that they had to stop to launch and recover their aircraft and they could not, therefore, operate in formation with other warships. While stopped they were vulnerable to attack by U-boats or, during a fleet action, by enemy destroyers.
They could each carry three seaplanes at first, and both their workshops and stowage for spare aircraft parts were less extensive than those in Ark Royal, limiting their use in extended operations.
In 1915 they were both reconstructed by Cunard in Liverpool. With more extensive aircraft- operating arrangements they were both subsequently able to carry four seaplanes. The most obvious change was the replacement of the canvas hangars by a more permanent weatherproof steel hangar structure aft. Aft of this were two cranes fitted in lieu of the derricks for operating aircraft, although a derrick was retained forward. The hangar was heated by fourteen steam radiators to keep the aircraft warm while they were stowed inside, and its interior bulkheads included stowage racks for bombs and air bottles. Rails were fitted on the deck for trolleys on which the bulky seaplanes were moved.
The hangar was closed by roller shutters. The workshops were improved and extended to include armament, W/T and engine facilities. The last contained lathes, a milling machine, a vertical drilling machine, hand shearing machines, an emery wheel, a coppersmith brazing hearth, four benches with vices, an engine washing tank and trolleys for moving engines. There was even a portable forge and
anvil, normally stowed in the hangar when not in use. A separate carpenters’ workshop contained a circular saw, a spindle moulding machine, an emery wheel and five benches with vices. Stores and spare parts could be lowered and raised between the workshops and hangar through a trunking. There was also a darkroom for processing photographs and a W/T room with a Marconi set, both for communicating with aircraft that were airborne and for rebroadcasting their information with a stronger signal.
Engadine in 1915, with a Short seaplane on its trolley on her after deck. She appears much as she did a year later, when she took part in the Battle of Jutland and launched the first aircraft to take part in a naval battle. (AUTHOR’S COLLECTION)
Both ships operated a carrier pigeon service with the necessary pigeon lofts and appliances for training the birds to return to the correct ship when released from aircraft. Given the unreliable nature of W/T, they were intended to bring back reconnaissance information and, in emergency, news of where and when their aircraft had ditched so that a search for the crew could be mounted.
Engadine, Riviera technical details
Displacement: 2,550 tons deep load
Dimensions: length 316ft
beam 41ft draught 13ft 8in
Machinery: 3 shaft Parsons steam turbines
6 Babcock & Wilcox water-tube boilers 13,800shp delivering up to
22.5 knots for short periods
Armament: 4 x 12pdr, 2 x Maxim
Protection: None
Fuel: 960 tons coal
Endurance: 1,250 miles at 15 knots
Complement: 197
Aircraft operating data
Flight Deck: None
Hangar: 80ft x 36ft x 20ft after full conversion in 1915
Catapults: None
Lifts: None
Aircraft: Four seaplanes
Aircraft fuel: Variable amounts of petrol carried in 2gal cans Air weapons: 18in torpedoes; 20lb and 100lb
bombs; grenades; 0.303in ammunition; flares and pyrotechnics.
Empress
Another of the cross-Channel ferries taken up from the South Eastern and Chatham Railway by the Admiralty in 1914, Empress was closely similar to Engadine and Riviera but machinery of only 8,800shp gave her a maximum speed of only 18 knots. Her more extensive modifications were carried out slightly later than those to the first two ships and differed slightly in detail. For instance, the hangar was 2ft longer and 1ft wider. Overall her capability was the same, including the workshops and stowage arrangements.
Campania (1914)
After the outbreak of war in August 1914 the Admiralty took up such large numbers of merchant vessels that it proved difficult to identify large, fast ships suitable for conversion into seaplane carriers to work with the fleet. New construction was expected to take too long and, in any case, the yards were full with orders for more cruisers, destroyers and other more conventional warship types.
Efforts were made to expand the number of passenger ferries being modified for the role but, other than those mentioned above, most available vessels were converted for minesweeping, minelaying and other important tasks. In November 1914 the old Cunard liner Campania was identified and purchased for conversion to an auxiliary cruiser. Twenty years old, she had won the Blue Riband for the fastest Atlantic crossing in 1894, but was now worn out and had actually been sold to T W Ward
& Co for scrapping. On the advice of the Director of the Air Department, however, she was converted into a seaplane carrier and her machinery overhauled to be able to maintain high speed with the fleet. The lack of watertight subdivision made her vulnerable to the effects of underwater damage but she proved to be an innovative and largely successful seaplane carrier.
The extensive modifications to convert Campania for her new role were carried out by Cammell Laird & Co of Birkenhead and included the construction of a large flying-off deck forward, from which it was hoped that seaplanes resting on wheeled trolleys could take off, thus obviating the need for the ship to stop and lower them into the water. In theory this made it possible for Campania to operate more closely with the battle fleet. A hangar capable of holding ten seaplanes was built under the flying-off deck. Workshops even more extensive than those in Ark Royal were fitted out and a considerable amount of space made available for the stowage of spares and stores. As with all the First World War aviation vessels it was assumed that many aircraft components would be made from scratch in workshops rather than delivered by manufacturers as spare parts.
Riviera in 1914, shortly after her initial conversion, with canvas hangars and derricks fitted in Chatham Dockyard. (AUTHOR’S
COLLECTION)
Campania as she appeared in May 1916. (AUTHOR’S COLLECTION)
A Sopwith Schneider seaplane was launched successfully from the deck in August 1915, albeit with little room to spare, and it was appreciated that the deck was too small to launch large reconnaissance seaplanes successfully. Consequently the ship was returned to Cammell Laird for more extensive alterations to be carried out from November 1915. To make the deck as long as possible, the forward funnel was taken down and replaced by two smaller funnels, one on each side of the extended deck. A small navigating bridge was fitted between the funnels, high enough for aircraft to be passed underneath it on to the flying-off deck. The after part of the ship was cleared to make space for an inflated kite balloon to be stowed and winched up. A hydrogen-making plant to fill the balloon, and winches for hauling it down, were installed at the same time. The alterations were
completed in April 1916 and Campania joined the GF in Scapa Flow with an air group of Sopwith Schneiders and Short Type 184s. She proved able to launch seaplanes given a reasonable amount of natural wind, but the ship’s performance remained marginal and she still had to stop in the water to recover her aircraft once they had landed, making it difficult for her to stay close the battle fleet.
TOP Campania after her initial conversion into a seaplane carrier in 1915. Note the single forward funnel and the small flying-off deck, which had only a shallow downward slope. The small hangar is visible aft of the gun mounting, and the two aircraft derricks in their stowed position are conspicuous. (R A BURT COLLECTION)
LEFT Campania after the modification which extended the flying-off deck aft between the new, split fore-funnels. Note the slope of the deck, which was intended to help aircraft accelerate to flying speed in the short distance available. (AUTHOR’S
COLLECTION)
BOTTOM LEFT A Short seaplane on its trolley is ranged ready for take-off from Campania. (AUTHOR’S COLLECTION)
Campania earned a place in history as the evolutionary link between the early seaplane carriers and the first true aircraft carriers.
Campania technical details
Displacement: 20,611 tons at deep load
Dimensions: length 622ft overall
beam 65ft draught 29ft 3in
Machinery: 2 shaft reciprocating steam engines
13 cylindrical boilers 30,000shp giving up to 23 knots for short periods
Armament: 6 x single 4.7in LA; 1 x single 3in HA
Protection: None
Fuel: 3,270 tons coal
Endurance: 2,600 miles at 21 knots
Complement: 600