The Evolution of the Aircraft Carrier: the First Two Decades Pt. 4 by Dan Linton
Writer: Dan Linton

 

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HMS Hermes and HMS Eagle

 

HMS Hermes (picture 1), the first ship ever to be built from the keel up as an aircraft carrier, would provide ideas and information to BritainÆs main rivals (but WWI allies), Japan and the United States but would not in fact be completed until after IJN Hosho (picture 2) and USS Langley (picture 3) were commissioned. All through her building and testing, Hermes would be linked to HMS Eagle (picture 4), a battleship being converted into an aircraft carrier, in a process of cross-fertilization of problems and solutions. Because the two ships were built at the same yard, they competed for the same labour and resources. According to Friedman, ôHermes was laid down on time, 15 January 1918; but after that progress was slowed because the battleship, which was quite far advanced, could be completed more quickly.ö(1) Later, details of EagleÆs conversion were made available (with enthusiasm according to some sources; somewhat grudgingly according to others) to France to assist in that countryÆs conversion of the BΘarn to an aircraft carrier(2) (picture 5). Thus Hermes and Eagle were, in a sense, the first carriers of the three other countries that in the 1920Æs built and operated aircraft carriers. And they set the pattern of having a superstructure or island possessing funnels, navigating bridge, flight deck management, and usually a æfighting topÆ to direct gunfire û all this on the starboard side of the ship. Since Hermes and Eagle, only Furious (flush-deck), and two Japanese carriers with port superstructures, have strayed from this pattern.

      
    
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HMS Hermes: A Carrier from the Keel Up

HMS Hermes, named after the seaplane carrier that had been torpedoed and sunk early in the war, was ordered in April, 1917. She was to have a good speed (25kts) and only medium calibre guns as surface action was to be avoided.(3) She was built with a modified cruiser hull, displacing 13,000 tons. Her machinery, producing 40,000 shp through two shafts gave her a 25kt maximum speed, but even at an economical cruising speed of 18kts, her endurance was only 2930 miles. Her overall length was 600Æ(184.6m) with a 70Æ(21.5m) beam and a 26Æ(8m) draught. She was designed to carry 20 aircraft in an armoured hangar 400Æx50Æx16Æ(123mx15.5mx5m)(4). She had forward and aft lifts 46Æx47Æ but in a cruciform pattern, a feature to be found on most of the early aircraft carriers but not carried over into 1930 designs.(5)(picture 6) Part of the design philosophy included the idea that were she not successful as a carrier, she could be converted easily into a cruiser.(6)(picture 7) She was not laid down until Jan.15, 1918 by which time the design had changed. As with Argus, she was originally designed with a slipway aft for recovering seaplanes directly and as with Argus this feature was deleted. Nonetheless, the early carriers were expected to operate in a secondary role as mobile bases for floatplanes and so all had cranes to lift planes in and out of the water; all carried floats to convert planes to floatplanes on the flight deck or in the hangar; and the hangars were high enough to accommodate aircraft plus floats on trolleys. (7)(picture 8). The hangar deck, like that of Argus, was armoured and isolated from the rest of the ship but there were penalties for this arrangement and one of them was the wasted space in the open well beneath the lifts (elevators)(8), and another was that if any explosion did occur in the hangar deck, its effects would be magnified(9). In the original design there were to be two islands with a clear 46Æ (14m)between them, but the experience with HMS Furious in 1917 and 1918 led to a decision in June, 1918 to adopt a one-island design with the island on the starboard side.(10) And this decision was taken by the Assistant Director of Naval Construction J.H. Narbeth because it was believed that higher powered vessels required more conventional uptakes than low-powered vessels like Argus, thus a flush-deck for Hermes (and by extension, Eagle) was not a desired solution.

And there has always been a controversy as to why the starboard sided was chosen. Flight Commander Hugh Williamson, who showed a model of a seaplane carrier proposal to Narbeth in Sept.1915 with bridge, funnel, and mast on the starboard side, claimed his choice was arbitrary. Some have claimed that the choice, made consciously or not, was based on the fact that the British drive on the left. But Narbeth said he made the choice of the starboard side because of what pilots told him: to clear the ship after a failed approach, pilots would turn to the left. ôIn a rotary, the entire engine revolved rapidly around a fixed crankshaft, which imparted a gyroscopic ûtorque effect, tending strongly to nose an aeroplane down in a right turn, and up in a left turnö.(11) And many WWI aircraft were rotary-powered. Originally, Hermes was to be completed in July, 1919, but she was not in fact commissioned until July of 1923. Her completion was delayed by the competition for resources with Eagle; by the end of wartime pressure because of the Armistice; by budget cuts; and by the need to wait for test results from Eagle. In May of 1921 came a serious revision as the lifts (elevators) had to be moved farther apart (370Æ/94m) from the original 240Æ(71m) and there were at least three changes in the shipsÆ armament during construction.(12) Finally, the ship was built with an aerodynamic æhumpÆ aft, leaving an 18ö depression and into this the fore and aft wires were anchored.(13) (pictures 9 and 10). The carrier that was finally sent to sea had good sea-keeping qualities and sported new aircraft (Parnell Panthers, Nieuport Nightjars, and Fairey Flycatchers û pictures 11,12, and 13).(14) She spent most of her career in the Far East, having a white hull and buff upperworks but was essentially the only carrier the British regularly stationed east of Suez. (picture 14) She was lost on 5 April, 1942 when swamped by waves of aircraft from carriers of the Imperial Japanese Navy. (pictures 15 and 16)

      
      
      
  
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HMS Eagle: the First Battleship Conversion

HMS Eagle began as the Chilean battleship Admiral Cochrane but work on her was stopped when the war broke out and her 14öguns were diverted to monitors. In casting around for hulls to support the dream of a massive airborne torpedo attack on the German High Seas Fleet in its home ports, the Admiralty took note of Admiral Cochrane û its hull and machinery were nearly complete; the boilers were on board; and the armour was in the yard but not yet fitted. (15) The conversion was ordered on 25 January 1918 and the ship re-named Eagle in March of that year. It was predicted that she could be completed in nine months and thus be ready before Hermes (predicted for June,1919).(16) Her original conversion envisioned two islands, one to port and one to starboard, but staggered so that one began closer to the bow, and the other closer to the stern. Cross-bracing, leaving a 20Æ(6m) height clearance , would join the two islands which had 68Æ(21m) of clear flight deck between them. A 400Æ hangar, varying in width from 44Æto 66Æ would support 26 Sopwith Cuckoos.(17) By June 1918 it was known that the twin island design was hopelessly flawed, and a single large island 130Æ (40m) long but only 15Æ(4.6m) wide, having twin funnels was approved. It had been designed in April, 1918, as an alternative. But even then construction was held back until the tests on Argus with a dummy island were completed.(18) As delivered, Eagle was 667Æ (205m) long overall with a beam of 96Æ (30m): the flight deck was 652Æ (201m) x 115Æ(35.5m). ShipÆs draught was 26Æ(8m) on a displacement of 22,000 tons. (picture 17) Her 4 shafts could make 24kts and she had essentially the same pointed flight deck at the bows as Hermes (picture 18), the same round-down at the stern (picture 18), and the same 18ö æhumpÆ on the rear landing area. (picture 19). From many angles Eagle looks like a sister ship to Hermes. Her aft elevator was a 46Æx30Æ rectangle while the forward elevator, like those on Hermes, was 46Æx47Æ but cruciform in shape.(19) (picture20) Her flight deck was her strength deck and she had only half the armour that had originally been designed for her as a battleship. Launched in June, 1918, at which time the hull was formally purchased from Chile, EagleÆs completion was delayed by a number of factors, the issue of the island or superstructure being only one of them. By April, 1920 only two boilers and one funnel were operating and neither of the lifts were working; all the same, trials began on May 28, continuing into the bad weather of June 1, testing the ability of aircraft to come safely aboard. Despite the captainÆs negative views (he thought the island a nuisance), pilots appreciated the height and alignment reference the island provided and found the turbulence from the exhaust gases to be manageable. On Sept. 24, 1920 the Admiralty decided to complete the ship as an aircraft carrier, and also agreed that the island on Hermes could be shorter and wider than that of Eagle.(20) Eagle was commissioned February 26, 1924. She had bulges added in 1921 and this improved her handling. Her weaknesses were those of Argus and Hermes û slow speed, small air wing; and limited endurance. (picture 21) In EagleÆs case endurance was limited not so much by her oil reserves as by the fact that she carried only 8000 gallons of aviation gasoline and might often use up 1500 gallons or more in a single day of flying. Her hangar deck was the first to have a salt-water spray system installed to suppress fires (1929)and she was given the first four sets of foam generators capable of covering the entire flight deck with foam (1933)(21). Much of her service life was spent in the Mediterranean (picture 22) and it was there on convoy escort duty to Malta, that U-73 found her and fired four torpedoes, all of which hit. Eagle sank on August 11, 1942: 789 men were saved but 160 lost their lives. (picture 23)

      
      
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The Washington Naval Conference

By the time Hermes and Eagle entered service, the Washington Naval Conference had established that Britain would be allowed 135,000 tons in carriers, the same total as the United States, while Japan would be allowed 81,000 tons. Carriers were limited to 27,000 tons maximum with a maximum permitted armament of ten 8ö guns. Interestingly, a carrier under 10,000 tons would not be counted against a nationÆs limit, the prevailing belief being that no effective ship could result from such a limited displacement.(23) USS Langley, IJN Hosho, and the Royal NavyÆs Argus were classed as experimental ships, and both the Japanese and the Americans were granted an exemption to convert two almost complete battleships and two almost complete battlecruisers, each nearly 40,000 tons. But the Royal Navy, owning in 1924 three of the only five aircraft carriers on earth, was already behind. Besides their massive tonnage, the new Japanese(picture 24 Akagi; picture 25 Kaga) and American carriers(picture 26 Lexington; picture 27 Saratoga) would each have an air wing equal to the total of Argus, Hermes, and Eagle, and would also be capable of 30kt.speeds. Only Furious and her sisters could match the speed of the projected giants but their narrow hulls restricted the size of their air wings (they would be built with double hangars to try to overcome this handicap); otherwise, the British had no other readily convertible hulls. And a new build, in the climate of the 1920Æs, was simply not going to happen. When a new British carrier, Ark Royal, arrived in 1937 (she had been ordered as much as a Depression-era make work project as a reaction to a deteriorating international situation: picture 28) the British matched the number of carrier hulls possessed by the United States and Japan, but still had fewer aircraft than the other two powers. How had this happened?

And the simple answer is that British thinking ran along the lines of a replay of Jutland, and was also influenced by two factors that did not affect the Americans or Japanese. First, Argus, Hermes, and Eagle were designed specifically to support the Sopwith Cuckoo, an excellent plane with a wide undercarriage, folding wings, enough power to carry an 18ö torpedo, and four hours endurance (picture 29). Ninety Cuckoos were delivered by the time of the Armistice and then production, originally projected at 200, ended. These were the weapons to be used against the German High Seas fleet, forcing it out of its safe havens and into the waiting guns of the Grand Fleet. And to get as many carriers as soon as possible, the Royal Navy accepted a speed which by the mid-1920Æs was slower than their projected rivals. And there was no German High Seas Fleet in 1924, nor would there be one in the foreseeable future. What role, then, could carriers play? Protecting merchant shipping was obvious, as was reconnaissance for the fleet, but unlike the Japanese or Americans, the British had a world-spanning empire and even the six carriers they would possess by 1930 were spread very thin. This was the second factor. All through the 1930Æs, Hermes was the only carrier east of Suez. Further, the British expected to operate in areas (North Sea; Mediterranean) where their ships could be attacked from land bases. Thus the emphasis on armoured hangars at the expense of larger airwings, the exact reverse of American and Japanese preferences. These operating areas also explain why the British resisted deck parks û planes deteriorated rapidly in the cold, wet, salt-impregnated air masses of the North Atlantic û better to keep them dry in the hangar. Contrast this with the Gulf of Mexico and the waters off Hawaii where American carriers spent most of their cruises.(picture 30). The original three British carriers, direct products of the first great war, were too slow and too limited compared with everything that came after them. And there was a third factor in BritianÆs losing her lead. As will be seen in a later article, the very nature of BritainÆs military organization was also a loadstone on the development of aviation in the Royal Navy.

      
      
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Attacking the Enemy; Defending the Ship

The Sopwith Cuckoo has already been mentioned. It, and the other aircraft that landed on British decks in the 1920Æs and 1930Æs were usually two-seaters, most often modified from land-based machines. Torpedo-bombing was what the British specialized in, to the absence of designing specific dive-bombing aircraft. Most exercises (picture 31) that the British held usually involved attacks on battleships û sinking was not anticipated û rather, slowing down the enemy was the objective so the main fleet could apply the coup de grace. The legacy of Jutland lived on.(24) There appear to have been few if any exercises involving carrier on carrier attacks (picture 32) û but then, no European enemy had a carrier until the Graf Zeppelin was launched in 1938 (and she was never completed). Since British carrier operations might often be close enough to be vulnerable to land-based bombers, the problem of ship defense had to be considered. When first designed as many guns as possible of at least 6ö were ordered since it was expected that a carrier and her escorts, sailing ahead of the fleet, might come in contact with an enemiesÆ reconnaissance cruisers: against such ships the carrier needed guns to effect an escape but if any of her air wing were still aloft --- well, then it was best to avoid a gunfight. At one point in its construction, Eagle was to have been fitted with two triple torpedo tubes, but these were deleted.(25) In the late 1920Æs and 1930Æs 4ö H/A (High Angle) guns were added: their purpose was to interfere with medium level bombers. Armoured hangars and H/A guns were actually considered more effective than the shipÆs fighters. With small air wings, limited aircraft endurance, no radars, and with radio silence standard operating procedure in the Royal Navy (26) û attempting a Combat Air Patrol would simply not be effective, thus the emphasis on passive defensive measures. But such measures could do little against dive bombers, and cruiser armour meant that these ships were vulnerable to submarines. Eagle was lost, as were Courageous and Ark Royal, to submarines and Hermes was lost to carrier aircraft, particularly dive bombers for which she had no effective defense: even had all of her aircraft û an air wing of about 15 in 1942 û been fighters, the result would have been the same. Eagle and Hermes served well, particularly in that one role for which capital ships are so well suited in peacetime showing the flag.

  
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Modeling HMS Hermes and HMS Eagle

As any reader of these articles have come to expect, one can find these carriers represented in 1:1250 scale in metal. Neptun 1115 shows Hermes as she was in 1938 and Neptun 1116 has Eagle as she was at the time of her sinking in 1942. Nothing, as best I could determine, exists in plastic in any scale for these vessels; there are, however, resin kits. The German firm, H-P Models makes resin kits in 1:700 scale of HMS Hermes (picture 33) and HMS Eagle (picture 34). The magazine Model Boats years ago presented line drawing by Michael Ainsworth in 1:600 scale: one of these drawings shows HMS Hermes as she was in 1934.(27) The Warship Profile series, produced in England in the early 1970Æs, featured HMS Eagle in no.35.(picture 35) I considered purchasing this to aid in researching for this article (I bought no.23 and no.24, both featuring HMS Furious, at a reasonable price) but long out of print, no.35 is offered on used books websites at outrageous prices û from $40 to $80 for what is essentially a 24-page pamphlet. And while the pictures might be useful, there are insufficient hull cross-sections for modeling. Cross-sections are found in Profile Morskie #97 (picture 36), a very handy book at 21 Euros (note the colour camouflage drawing, picture 37). On the Profile Morskie website (www.profilemorskie.home.pl) you can also order plans via PDF sent to your e-mail for Eagle as she was in 1942 at the time of her loss: for a set of 1:200 plans the cost is 14 Euros; and for a PDF that comes in 1:350 and 1:700 together the cost is also 14 Euros. Aside from the above, I could find no plans for Hermes or Eagle among the usual suspects (e.g. Taubman Plans service). Again, especially for HMS Hermes, one needs to contact the Imperial War Museum for plans. I am surprised at the absence of useful modeling materials for ships whose design was so essential for all that came after them.

      
  
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Extra Images:

I am providing these for anyone who might find them useful for modeling: they were not necessary for the article as it is, but for modeling there is no such thing as too many pictures. The first three are of Hermes (pictures 38-40) and the last six are of Eagle (pictures 41-46).

Next: USS Langley

      
      
  
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Endnotes:

1.Friedman, Norman, British Carrier Aviation: the Evolution of the Ships and their Aircraft, p. 73

2. Preston, Anthony, Aircraft Carriers, p. 42

3.Preston, p.23. It was expected that the early carriers might be met by the reconnaissance cruisers of a hostile fleet, thus the issue of what guns to be put on the carrier: this will be discussed in more detail later in the article.

4.The 20 aircraft of 1924 became only 12-14 by the time of her loss in 1942, such was the growth in the size of aircraft. Preston, p.28

5. ôThe forward lift in most carriers was T-shaped so that aircraft could taxi onto it and be struck down with wings spread prior to being folded in the hangar where all aircraft were stowed when not flying.ö Preston, p.28

6. Friedman, p.73. She had the protection of a Raleigh-class cruiser and the powerplant of a D-class light cruiser.

7. Hobbes, D., Aircraft Carriers of the Royal and Commonwealth Navies, p. 17

8. Hobbes, p.16

9. Nevertheless, the armoured hangar deck served the British well, particularly during kamikaze attacks in the Far East in 1945.

10. Robbins, G., The Aircraft Carrier Story, p.66

11. Layman, R.D., Before the Aircraft Carrier: the Development of Aviation Vessels 1849-1922, pp.69-71

12. Friedman, p.84

13. Preston, p.17. This system was removed in 1927

14. Beaver, p.13

15. Robbins, p.57, and Friedman, p.74

16. Robbins, pp.58-59

17. Friedman, p.74

18. Friedman, p.76; Robbins, p.59; Preston, p.27

19. Hobbes, p.79

20. Hobbes, pp.79-80; Preston, pp.28-29

21. Preston, pp.42-44

22. Friedman, p.87

23. Although, as we shall see in a later article, this did not stop the Japanese from trying.

24. Nevertheless, this British attachment proved its worth in May, 1941 against the KriegsmarineÆs Bismarck.

25. Friedman, p. 82

26. Cryptology had given the British several advantages in the Great War and they did not want to give adversaryÆs similar opportunities.

27. Ainsworth collected a number of them together and published Warships in Miniature; the HermesÆ diagrams are on page 44 of this collection.



Bibliography:

Beaver, Paul, The British Aircraft Carrier, 3rd ed., Patrick Stevens Ltd., 1987

Friedman, Norman, British Carrier Aviation: the Evolution of the Ships and their Aircraft, Conway Maritime Press, 1988

Hobbs, D., Aircraft Carriers of the Royal and Commonwealth Navies, Greenhill books, 1996

Layman, R.D., Before the Aircraft Carrier: the Development of Aviation Vessels 1849-1922, Conway Maritime Press, 1989

Preston, Anthony, Aircraft Carriers, Galahad Books, 1979

Robbins, G., The Aircraft Carrier Story, Cassel & Co., London 2001

Ships of the World, History of British Aircraft Carriers, no.649, Oct. 2005, ed.T.Kizu, Kaijinsha Co.Ltd., Japan

Picture Credits:

Main Picture: Ships of the World, History of British Aircraft Carriers, p. 41

Last Picture: Ships of the World, p.36

Picture 1: Ships of the World, p.40

Picture 2: Japanese Navy; public domain

Picture 3: Naval History and Heritage Command (NHHC) NH81279

Picture 4: www.digilander.libero.it/shinano

Picture 5: French Navy; public domain

Picture 6: Ships of the World, p.41

Picture 7: Ships of the World, p.40

Picture 8: Ships of the World, p.42

Picture 9: Ships of the World, p.43

Picture 10: www.digilander.... Assonometric diagram

Picture 11: FAA; public domain

Picture 12: FAA; public domain

Picture 13: FAA; public domain

Picture 14: Ships of the World, p.35

Picture 15: Royal Navy, public domain

Picture 16: Royal Navy, public domain

Picture 17: Ships of the World, p.36

Picture 18: Ships of the World, p.37

Picture 19: Royal Navy, public domain

Picture 20: www.digilander.... Assonometric diagram

Picture 21: Ships of the World, p.37

Picture 22: www.digilander....

Picture 23: Royal Navy, public domain

Picture 24: www.digilander....

Picture 25: www.digilander....

Picture 26: NavSource 020242

Picture 27: NavSource 020352

Picture 28: NHHC photo # NH 85716

Picture 29: www.aviastar.org/air/england/Sopwith_Cuckoo.php

Picture 30: NavSource 020205

Picture 31: Royal Navy, public domain

Picture 32: FAA Museum, Yeovilton, in Profile Warship 24, p.274

Picture 33: www.hp-models.com

Picture 34: www.hp-models.com

Picture 35: taken from a used book website

Picture 36: www.profilemorskie.home.pl

Picture 37: www.profilemorskie.home.pl

Picture 38: www.digilander...

Pictures 39-43: Royal Navy, public domain

Pictures 44-46: www.digilander...



 


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  Photos and text © 2010 by Dan Linton

April 28, 2010

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