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The veteran WW1 cruiser HMS Caroline, now subject to preservation as a museum ship, is a little-known pioneer of naval aviation. As restoration work is now underway, much attention will rightly be devoted to the ship’s role in the Battle of Jutland, the major engagement between the German High Seas Fleet and the British Grand Fleet in June 1916. However, the following year, the C-class cruiser HMS Caroline became one of the earliest operational ‘aircraft carriers’.
HMS Caroline can be seen at the Alexandra Graving Dock in Belfast, and although it will be some time before she is open to the public, it is possible to inspect the vessel externally from a very short distance. She differs somewhat from her WW1 appearance, mainly in the lack of guns and the large drill hall built amidships, but in many respects is still in remarkably original condition.

There are three surviving WW1 warships in the UK today – HMS President (formerly HMS Saxifrage), currently moored on the Thames, HM Monitor M.33 in dry dock at Portsmouth, and the Caroline. It is perhaps a mark of how far naval flying advanced from its embryonic state in 1914 that two of the three vessels have important links to naval aviation. (Read more about M.33 here).

Experiments in launching aircraft from warships had begun in the years before the First World War, almost as soon as aeroplanes became a practical means of transport. Eugene Ely took off and landed a Curtiss pusher from anchored US warships in October 1910, and just over a year later, in January 1912, Lieutenant C.R. Samson flew a Short S.38 from a ramp mounted to the bow of HMS Africa. The Royal Navy’s experiments were somewhat more sustained than those of the US Navy, and included the first take-off from a ship at sea, in May 1912. HMS Hermes was commissioned the following year as the parent vessel for the Aeroplane and Airship section, with a hangar and launching ramp fitted. Four cruisers had fixed ramps fitted and carried floatplanes in the early part of WW1, but the practical difficulties proved too difficult and, from August 1915, naval aviation from ships was restricted to dedicated seaplane carriers.

Nevertheless, the value of flying aircraft directly from warships at sea was recognised, and trials with launching ramps took place aboard the battle cruisers HMS Renown and HMAS Australia in 1917. One reason it had become important to find ways of launching high-performance aircraft at sea was the increasing threat to naval operations by German naval zeppelins. Much has been made of the early strategic bombing role these aircraft fulfilled, but of equal significance was their ability to reconnoitre for the German navy, using their excellent range and loitering ability. Royal Navy operations could lose the element of surprise at a stroke, with no possibility of hitting back.

It was around this time that fitting launching ramps to light cruisers was again mooted. Two of Caroline’s sister C-class cruisers, HMS Caledon and HMS Cassandra, were among the first vessels so fitted. These ramps were built on the foredeck, and extended from the bridge structure out over the bow gun in such a way that its movement was not impaired. They added little weight to the ship, so the Commander-in-Chief ordered that one ship in each of the light cruiser squadrons should be so fitted. Caroline, of the 4th Light Cruiser Squadron, had her platform fitted in 1917-18, to carry a Sopwith 2F.1 ‘Camel’ single-seat scout aircraft.

HMS Caroline’s flying-off platform with Sopwith Camel (NMRN)

Although much smaller than capital ships such as battleships and battle cruisers, light cruisers had the advantage of speed and manoeuvrability. The C-class, with their powerful steam-turbine machinery, could reach speeds approaching 30 knots, meaning that an aircraft would need very little take-off roll to become airborne.
Caroline’s Camel was never called upon to launch in anger. However, the potential of the arrangement could be seen in the flight by Flight Sub Lieutenant B.A. Smart on 21 August 1917. Smart was the pilot of a Sopwith Pup carried by HMS Yarmouth of the 3rd Light Cruiser Squadron. At 0530, a zeppelin was spotted, this being L23, a ‘Q-class’ airship, veteran of 51 reconnaissance missions and three bombing raids. Yarmouth turned into wind and Smart used the Pup’s excellent climbing capability to put his aircraft above the zeppelin, and was able to take advantage of the lightly loaded biplane’s manoeuvrability to keep himself out of the defensive machine guns’ fields of fire. Making his final attack from around 100 yards, Smart saw incendiary bullets enter the airship’s stern, and L23 quickly caught fire and crashed.

Caroline’s experience with the flying-off platform was less dramatic. It seems that a number of flights were made from her, as no fewer than eight Camels are logged as having been aboard (compared with just one or two in some cases) . Several sources report that the Caroline’s ramp was used for experiments with flying off aircraft, and this may have been the case, although some 22 light cruisers were fitted with platforms during this period.

An unconfirmed legend (see this post on the Great War forum) has it that Captain H.R. Crook, in command from 1916 until the end of the war, was frustrated by the need to turn his ship into wind to launch the Camel, followed by the inconvenience of having to wait for aircraft and pilot to be lightered to the cruiser. The story goes that after one successful launch, the pilot flew further down the coast than anticipated, leaving the Captain with a five-hour wait to recover the Camel, whereupon he declared that the pilot could fly as far as he liked, as neither aircraft nor aircrew would be allowed back on the Caroline.

Whatever the truth of this, there were certain impracticalities to the fixed foredeck launching ramps that no doubt became apparent during this period. The ship had to be turned into wind, reducing its freedom of manoeuvre and meaning it would have to leave the line of battle. Furthermore, most cruisers lacked a crane to bring the aircraft back on board.

Flying operations of this nature came to an end in 1919 when the Sopwith 2F.1 was withdrawn from service. It seems that the Camel’s replacement, the Nieuport Nighthawk, was not considered for launching from ship platforms, although steps were taken to modify Sopwith Snipes for that use. The RN had to wait until the introduction of the Fairey Flycatcher in 1924 for this kind of flying to be resumed.

By this time, wartime experience had led to developments in the platforms used for launching aircraft. A revolving platform was specially designed and wind-tunnel tested using models of a C-class cruiser, enabling aircraft to launch into the wind without the ship having to change course. Capital ships were able to use gun-turrets as turntables, and platforms were erected on top of the barbettes.

These developments were rendered obsolete relatively quickly, by the introduction of catapults. Nevertheless, the use of aircraft launched directly from warships for reconnaissance or defence, without needing a specialised ship, was successfully proven by Caroline and her sisters.

See a gallery of images from the National Museum of the Royal Navy here