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
Anne
Originally the mercantile Anne Rickmers owned by the Rickmers Reismuhlen Reederai and Schiffbau, this vessel was captured by the RN in Port Said on the outbreak of war in August 1914 and given temporary modifications to allow her to operate as a seaplane carrier. She operated in the Eastern Mediterranean, where canvas hangars and awnings were sufficient to protect her aircraft against the elements. Workshops and stores facilities were extemporised since the vessel’s service was expected to be temporary.
Anne technical details
Displacement: 4,083 tons deep load
Dimensions: length 367ft 1in
beam 47ft 7in draught 27ft 3in
Machinery: single shaft triple-expansion
reciprocating steam engine Coal-fired boilers
11 knots maximum
Armament: 1 x 12pdr; 1 x 0.303in machine-gun
Protection: none
Fuel: coal
Endurance: not known
Complement: not known
Aircraft operating details
Hangars: canvas windbreaks
Aircraft: Three seaplanes
Aircraft fuel: petrol carried in 2gal cans
Air weapons: grenades and 0.303in gun ammunition
Ben-my-Chree
Ben-my-Chree was requisitioned from the Isle of Man Steam Packet Company on 1 January 1915 and her modification into a seaplane carrier took advantage of the experience gained with the cross- Channel steamers that had been requisitioned a few months earlier. Her name translates into English as ‘Woman of My Heart’. She was fitted with a small flying-off deck, 63ft long, over the forecastle but this proved too small to be able to launch even lightweight Sopwith Schneiders and was subsequently removed. Since she was considerably larger than Engadine, the conversion was more extensive and included a hangar that was slightly larger and more sophisticated workshops capable of testing as well as manufacturing and repairing aircraft components.
Anne in 1915. (AUTHOR’S COLLECTION)
The ship had the dubious distinction of being the only aircraft carrying vessel to be sunk in action during the First World War, after hits from Turkish shore batteries set her on fire. The situation was made worse by the explosion of petrol vapour from ‘empty’ 2gal aircraft fuel cans stowed in and around the hangar. Full petrol cans also contributed to her loss as they burned furiously and beat back all attempts to fight the fire. Subsequent analysis of the loss influenced all future British aircraft carrier designs, the majority having enclosed hangars that were isolated from the rest of the ship by airlocks and good ventilation to prevent petrol fumes building up. British hangars subsequently had metal decks, rather than wooden ones which could absorb fuel, and copious supplies of first-aid fire appliances. As with all ships fitted with coal-fired boilers, the maximum speed quoted could usually be maintained only for short periods, and performance varied with the type of coal in use. Welsh steam coal was considered the best.
Ben-my-Chree on fire aft and sinking off Castelorizo Island in 1917. (AUTHOR’S COLLECTION)
Vindex; note the flying-off deck over the forecastle and derricks forward for lifting fighters out of the small hangar under the deck. (AUTHOR’S COLLECTION)
Ben-my-Chree technical details
Displacement: 3,888 tons deep load
Dimensions: length 375ft beam 46ft draught 16ft
Machinery: 3 shaft steam turbines
4 cylindrical double-ended boilers
14,500shp giving 22 knots for short periods
Armament: 4 x single 12pdr LA;
1 single 12pdr HA;
2 x single 3pdr
Protection: none
Fuel: 552 tons coal
Endurance: not known
Complement: 250
Aircraft operating data
Flight deck: take-off deck forward 63ft long and 12ft wide Hangar: 80ft x 42ft x 21ft
Lifts: Derricks forward and aft for lifting seaplanes on and off the water Aircraft: Up to six seaplanes
Aircraft fuel: Variable amounts of petrol stowed in 2gal cans Air weapons: 18in torpedoes; small bombs;
0.303in gun ammunition; flares and pyrotechnics
Vindex (1915)
Another of the Isle of man Steam Packet Company’s vessels taken over by the Admiralty, Vindex was originally named Viking. She can be considered as the first of the ‘second generation’ of small aircraft carrying ships, and was intended from the outset to launch fighters from a deck forward to prevent German reconnaissance airships reporting the fleet’s position. The arrangement for seaplanes aft followed the lines that were by then considered normal, supported by a general-purpose workshop. By early 1915, however, experience already showed that seaplane fighters were unable to intercept Germany’s rigid airships over the North Sea. There were several reasons for this. The carrier had to stop to swing the fighter out on to the water, giving the enemy aircraft warning that a launch was imminent, and the floats limited the fighter’s modest performance to the extent that the German airships could both out-climb and, usually, out-run them. If all else failed, the airship could dump ballast and climb rapidly above the fighter’s ceiling. No German airship was successfully intercepted by a seaplane fighter in the entire war. The solution, already clear in 1915, was to embark wheeled high-performance fighters such as the Bristol Scout that could take off from a small deck and climb rapidly to intercept and engage. The only drawback before landing decks evolved was that, if the fighter could not fly to the nearest point of land, the pilot had to ditch close to a friendly warship.
Apart from the obvious danger to the pilot, the aircraft was a writeoff and had to be considered as a
‘one-shot’ system, rather like modern anti-aircraft missiles.
Ben-my-Chree as she appeared after conversion to a seaplane carrier in 1915. (AUTHOR’S COLLECTION)
Vindex’s conversion into a seaplane carrier included a box-type hangar aft. An operating deck was built aft of it and seaplanes were moved by two electric cranes fitted against the after hangar bulkhead. A second hangar was built forward under the small take-off deck. It was just large enough to carry two dismantled fighters which were carefully stowed to allow them to be quickly assembled (or dismantled). Two derricks, one either side of the ship, were fitted forward of the bridge to lift fighters out of the small forward hangar. At first these were to be Sopwith Babies, but the deck was too short for them and in October 1915 the ship’s officers obtained Admiralty permission to evaluate a Bristol Scout C wheeled fighter, the fastest fighter in RN service at the time. On 3 November 1915 Flight Commander B F Fowler RNAS took off from Vindex, which was steaming at 12 knots into a 15 knot wind. It took 20ft to get the tail up and achieve flying attitude, but he was airborne in 46ft. The aircraft had no brakes and had to be restrained by a ‘hold-back’ device which was released only when the pilot was happy that he had full power and the bridge was happy that the ship was steady into wind.
Further experiments refined the technique by putting the tailskid on a trestle so that the aircraft was in the flying attitude from the outset, reducing the take-off run required and the minimum wind speed needed over the deck. It proved possible to launch two aircraft within ten minutes of each other, most of the time being taken to hoist the second aircraft out of the cramped hangar on to the deck and then assemble it.
Vindex technical details
Displacement: 2,950 tons deep load
Dimensions: length 361ft
beam 42ft draught 13ft 3in
Machinery: 3 shaft direct-drive turbines
4 cylindrical, double-ended boilers
11,000shp giving 22 knots for short periods
Armament: 2 x single 12pdr LA
Protection: none
Fuel: 475 tons coal
Endurance: 995 miles at 10 knots
Complement: 218
Aircraft operating data
Flight deck: 64ft x 25ft
Hangar: aft 80ft x 36ft x 20ft
fwd not known
Aircraft: up to seven, normally five seaplanes and two wheeled fighters
Aircraft fuel: Variable amounts petrol in 2gal cans
Air weapons: 18in torpedoes; light bombs; 0.303in gun ammunition; flares and pyrotechnics
Raven II
Built as the merchant ship Rabenfels for the Deutsche Dampfschiffahrts Gesellschaft, this vessel was seized in Port Said at the same time as Anne Rickmers on the outbreak of war in 1914. She underwent a similar conversion and operated initially as a merchant auxiliary under the red ensign with a mixed Anglo-French air group.
Raven II technical details
Displacement: 4,706 tons deep load
Dimensions: length 394ft 5in
beam 51ft 6in draught 27ft 6in
Machinery: single shaft quadruple-expansion reciprocating steam engine
Coal-fired boilers 10 knots
Armament: 1 x 12pdr LA
Protection: none
Fuel: coal
Endurance: not known
Complement: not known
Aircraft operating data
Flight deck: none
Hangar: temporary canvas screens to protect aircraft
Aircraft: Up to six
Aircraft fuel: petrol carried in 2gal cans
Air weapons: grenades; 0.303in machine-gun ammunition; flares and pyrotechnics
Manxman
Manxman was built as a packet running to the Isle of Man and operated by the Midland Railway Company. She was slightly smaller but generally similar to Vindex and was converted into a seaplane carrier by Chatham Dockyard in 1916. The conversion took eight months and was more extensive than
the work on any of her predecessors, allowing specialised workshops for aircraft maintenance to be fitted out. It reflected all the experience gained in two years of wartime operations. The steel hangar aft was large enough to accommodate four seaplanes, which were moved into and out of the hangar on trolleys running on rails to help with ranging and striking down in rough weather. They were handled by two electric jib cranes on the after corners of the hangar. Manxman was fitted with a Marconi W/T installation with an aircraft type set as a backup.
The first innovation in the design was a second hangar built in under a new bridge, aft of a small working space and accommodating four aeroplanes. Forward of the working space was a flying-off deck 86ft long, built up over the forecastle. This hangar could accommodate four fully-assembled fighters and was originally intended for Sopwith Baby seaplanes, but the ship’s speed proved somewhat lower than the anticipated 21 knots and launching seaplanes proved to be impractical.
Instead she embarked Sopwith Pups with wheels, which could be operated perfectly adequately. The aircraft were pushed forward out of the hangar on to a working space and then lifted on to the flight deck by derrick. The space between the flying-off deck and the hangar structure was covered by a portable hatch which was slid forward under the deck to allow aircraft to be hoisted off the working deck and ranged; once they were through it was replaced in position to form an after extension to the flight deck, allowing aircraft prepared for launch and in a flying position with a trestle under the tailskid the maximum deck run possible. The same derricks hoisted aircraft inboard from lighters in harbour to replace those that had ditched after an operational launch. Manxman’s early trials with Sopwith Pups in 1917 proved so successful that this aircraft type was adopted for use throughout the GF. Given a suitable wind over the deck, a Pup could be airborne after a deck run of only 20ft.
Manxman, showing the cantilevered gantry aft which was intended to recover seaplanes while the ship remained in motion.
(AUTHOR’S COLLECTION)
The second innovation was a central cantilever gantry which extended aft from the hangar roof to a point beyond the stern, where a hook lowered from a trolley could be attached to a seaplane taxying at the same, slow, speed as the ship. The idea was that the ship would not have to stop to recover aircraft and, once the aircraft was attached to the hook, it was winched up clear of the water and the trolley moved it forward along the gantry to a point where it could be lowered on to a trolley on the working area and then wheeled into the hangar. The idea worked well in calm, sheltered water but was less successful in the open sea.
With a flight deck forward capable of launching fighters successfully but no means of landing them on, Manxman represented an intermediate step between the early seaplane carriers and Argus, the first truly practical aircraft carrier.
Pegasus with her two three-ton electric cranes aft of the hangar in their stowed position. (AUTHOR’S COLLECTION)
Manxman technical details
Displacement: 3,090 tons deep load
Dimensions: length 343ft
beam 43ft 1in draught 15ft 9in
Machinery: 3 shaft direct-drive steam turbines
3 boilers
6,500shp giving a nominal 21 knots
Armament: 2 x 12pdr LA; 1 x 6pdr HA
Protection: none
Fuel: 430 tons coal
Endurance: not known
Complement: 250
Aircraft operating data
Flight deck: 86ft x 28ft
Hangar: forward 42ft x 36ft x 18ft
aft 80ft x 36ft x 20ft
Aircraft: 8 (4 seaplanes aft; 4 wheeled fighters forward)
Aircraft fuel: variable amounts of petrol stored in 2gal cans
Air weapons: 18in torpedoes; light bombs; 0.303in machine-gun ammunition; flares and pyrotechnics
Pegasus
The next ship in sequence to be taken up for conversion was still under construction, and the Admiralty took the opportunity to carry out a more elaborate conversion and improve her machinery without unduly delaying the completion date. When taken over she had not been launched and,
although the hull was fairly well advanced, there was an opportunity to make greater internal modifications than in earlier ships. The spaces originally intended for passengers, horses and cargo were completely rearranged to provide accommodation, and stores, magazines and workshops were created in the lower part of the vessel. The workshops were particularly well equipped and included shops for airframe and engine work and carpentry and specialist areas for the ship’s hull, machinery and carpentry maintenance. She was also one of the first aircraft-carrying ships to have bulk stowage for aircraft fuel rather than stowing it in 2gal cans.
The structure and deckhouses above the awning deck were cut away to allow hangars to be constructed forward and aft which were similar to those in Manxman, the former being sited under a new bridge structure. By substituting Beardmore WB.IIIs, a folding-wing derivative of the Sopwith Pup intended specifically for embarked use, it proved possible to carry five fighters in the forward hangar, an improvement on the four fixed-wing Pups carried in Manxman. The central gantry aft was not repeated and two 3-ton electric cranes handled seaplanes and moved them on to and off the water.
Derricks were provided forward to move wheeled fighters on to the flying deck. As in Manxman, a sliding hatch was fitted aft of the flying deck to allow movement of aircraft up from the hangar and to extend the deck once it was back in place. A Type 2 W/T installation was fitted.
Pegasus was fitted with Brown Curtis steam turbines direct-geared to two shafts. Her boilers had originally been fitted to burn coal but were modified to burn FFO and the former coal bunkers were modified to serve as oil tanks. These improvements gave her a realistic sea speed of 20 to 21 knots and allowed her to steam at high speed for up to three days.
Since her conversion was more elaborate than that of her predecessors, Pegasus proved successful in service and was retained after the First World War.
Pegasus technical details
Displacement: 3,315 tons deep load
Dimensions: length 332ft 4in beam 43ft draught 18ft 9in
Machinery: 2 shaft Brown ik. Curtis directgeared steam turbines 6 oil-fired cylindrical boilers 9,500shp giving over 20 knots
Armament: 2 single 3in HA; 2 single 12pdr HA
Protection: none
Fuel: 360 tons FFO
Endurance: 1,300 miles at high speed
Complement: 258
Aircraft operating data
Flight deck: 82ft × 28ft
Hangar: forward 40ft × 40ft × 20ft aft 80ft × 40ft × 20ft
Aircraft: 4 seaplanes aft; 5 fighters forward; total 9
Aircraft fuel: l,300gal of petrol in bulk stowage
Air weapons: 18in torpedoes; light bombs; 0.303in machine-gunammunition; flares and pyrotechnics.
Nairana
Nairana had been launched when she was taken over by the Admiralty for conversion to a seaplane
carrier. Her machinery had not yet been installed but was at an advanced stage, so the boilers could not be modified to oil firing, limiting top speed to about 19 knots, but she was fitted out otherwise to the same standard as Pegasus, with extensive workshops and hangars fore and aft. She was slightly smaller, and thus able to carry only seven rather than nine aircraft. The arrangement of the flying-off deck forward was the same, with a sliding hatch to allow derricks to move aircraft out of the hangar on to the deck. Aft she had a gantry like the one in Manxman but considerably developed to allow it to be extended unsupported from the roof of the hangar for 50ft, and this variation proved more successful. The ship was fitted with a Type 2 W/T installation for communication with her aircraft and a secondary aircraft-type installation as backup.
Unlike previous ships that had been purchased outright by the Admiralty, Nairana was hired from her owners. The Admiralty had hoped that, together with Manxman and Pegasus, she would be able to form a ‘Flying Squadron’ capable of operating with the fleet without having to stop to launch and recover seaplanes, but their lack of top speed and the practical difficulties encountered with the gantry prevented realisation of this concept.
Nairana in a disruptive paint scheme in 1918, showing her enlarged and improved gantry aft. (AUTHOR’S COLLECTION)
Nairana technical details
Displacement: 3,070 tons deep load
Dimensions: length 352ft beam 4 5 ft 6in draught 14ft 5in
Machinery: 2 shaft geared turbines 6 water-tube coal-fired boilers 7,000shp giving up to 19 knots for periods
Armament: 2 single I2pdr LA; 2 single I2pdr HA
Protection: none
Fuel: 448 tons coal
Endurance: not known
Complement: 278
Aircraft operating data
Flight deck: 94ft × 23ft
Hangar: forward 40ft × 36ft × 20ft aft 80ft × 36ft × 20ft
Aircraft: 4 seaplanes aft; 3 fighters forward; total 7
Aircraft fuel: variable amounts of petrol carried in 2gal cans
Air weapons: 18in torpedoes; light bombs; 0.303in machine-gun, ammunition; flares and pyrotechnics