Chapter XVIII : AIRCRAFT AND NAVAL OPERATIONS

When once the flying machine had indicated its possibilities inconnection with land operations it was only natural thatendeavours should be made to adapt it to the more rigorousrequirements of the naval service. But the conditions are sovastly dissimilar that only a meagre measure of success has beenrecorded. Bomb-throwing from aloft upon the decks of battleshipsappeals vividly to the popular imagination, and the widespreaddestruction which may be caused by dropping such an agent downthe funnel of a vessel into the boiler-room is a favourite themeamong writers of fiction and artists. But hitting such anobjective while it is tearing at high speed through the water,from a height of several thousand feet is a vastly different taskfrom throwing sticks and balls at an Aunt Sally on terra firma:the target is so small and elusive.

Practically it is impossible to employ the flying machine,whether it be a dirigible or an aeroplane, in this field. Manyfactors militate against such an application. In the first placethere is a very wide difference between dry land and a stretch ofwater as an area over which to manoeuvre. So far as the land isconcerned descent is practicable at any time and almost anywhere.But an attempt to descend upon the open sea even when the latteris as calm as the proverbial mill-pond is fraught withconsiderable danger. The air-currents immediately above thewater differ radically from those prevailing above the surface ofthe land. Solar radiation also plays a very vital part. In factthe dirigible dare not venture to make such a landing even if itbe provided with floats. The chances are a thousand to one thatthe cars will become water-logged, rendering re-ascent a matterof extreme difficulty, if not absolutely impossible. On theother hand, the aeroplane when equipped with floats, is able toalight upon the water, and to rest thereon for a time. It mayeven take in a new supply of fuel if the elements be propitious,and may be able to re-ascend, but the occasions are rare whensuch operations can be carried out successfully.

In operations over water the airman is confronted with oneserious danger--the risk of losing his bearings and his way. Forinstance, many attempts have been made to cross the North Sea byaeroplane, but only one has proved successful so far. Theintrepid aviator did succeed in passing from the shore of Britainto the coast of Scandinavia. Many people suppose that because anairman is equipped with a compass he must be able to find hisway, but this is a fallacy. The aviator is in the same plight asa mariner who is compelled from circumstances to rely upon hiscompass alone, and who is debarred by inclement weather fromdeciding his precise position by taking the sun. A shipploughing the waters has to contend against the action of crosscurrents, the speed of which varies considerably, as well asadverse winds. Unless absolute correction for these influencescan be made the ship will wander considerably from its course. The airman is placed in a worse position. He has no means ofdetermining the direction and velocity of the currents prevailingin the atmosphere, and his compass cannot give him any help inthis connection, because it merely indicates direction.

Unless the airman has some means of determining his position,such as landmarks, he fails to realise the fact that he isdrifting, or, even if he becomes aware of this fact, it is by nomeans a simple straightforward matter for him to make adequateallowance for the factor. Side-drift is the aviator's greatestenemy. It cannot be determined with any degree of accuracy. Ifthe compass were an infallible guide the airman would be able tocomplete a given journey in dense fog just as easily as in clearweather. It is the action of the cross currents and theunconscious drift which render movement in the air during fog asimpracticable with safety as manoeuvring through the water undersimilar conditions. More than one bold and skilful aviator hasessayed the crossing of the English Channel and, being overtakenby fog, has failed to make the opposite coast. His compass hasgiven him the proper direction, but the side-drift has proved hisundoing, with the result that he has missed his objective.

The fickle character of the winds over the water, especially oversuch expanses as the North Sea, constitutes another and seriouslyadverse factor. Storms, squalls, gales, and, in winter,blizzards, spring up with magical suddenness, and are so severethat no aircraft could hope to live in them. But suchvisitations are more to be dreaded by the lighter-than-air thanby the heavier-than-air machines. The former offers aconsiderable area of resistance to the tempest and is caught upby the whirlwind before the pilot fully grasps the significantchance of the natural phenomenon. Once a dirigible is swept outof the hands of its pilot its doom is sealed.

On the other hand, the speed attainable by the aeroplaneconstitutes its safety. It can run before the wind, and meantimecan climb steadily and rapidly to a higher altitude, until atlast it enters a contrary wind or even a tolerably quiescentatmosphere. Even if it encounters the tempest head on there isno immediate danger if the aviator keep cool. This fact has beenestablished times out of number and the airman has beensufficiently skilful and quick-witted to succeed in frustratingthe destructive tactics of his natural enemy.

Only a short while ago in France, British airmen who went aloftin a gale found the latter too strong for them. Although themachine was driven full speed ahead it was forced backwards atthe rate of 10 miles per hour because the independent speed ofthe aeroplane was less than the velocity of the wind. But adirigible has never succeeded in weathering a gale; its bulk,area, and weight, combined with its relatively slow movement, areagainst it, with the result that it is hurled to destruction. All things considered, the dirigible is regarded as animpracticable acquisition to a fleet, except in the eyes of theGermans, who have been induced to place implicit reliance upontheir monsters. The gullible Teuton public confidently believesthat their Dreadnoughts of the air will complete the destructionof the British fleet, but responsible persons know full well thatthey will not play such a part, but must be reserved forscouting. Hitherto, in naval operations, mosquito water-craft,such as torpedo-boats, have been employed in this service. Butthese swift vessels suffer from one serious disability. Therange of vision is necessarily limited, and a slight mist hangingover the water blinds them; the enemy may even pass withinhalf-a-mile of them and escape detection.

The Zeppelin from its position 1,000 feet or more above thewater, in clear weather, has a tremendous range of vision; thehorizon is about 40 miles distant, as compared with approximately8 miles in the case of the torpedo-boat. of course an object,such as a battleship, may be detected at a far greater range. Consequently the German naval programme is to send the Zeppelin acertain distance ahead of the battleship squadron. The dirigiblefrom its coign of vantage would be able to sight a hostilesquadron if it were within visual range and would communicate thefact to the commander of the fleet below. The latter woulddecide his course according to information received; thus hewould be enabled to elude his enemy, or, if the tidings receivedfrom the aerial scout should be favourable, to dispose his vesselsin the most favourable array for attack.

The German code of naval tactics does not foreshadow the use ofdirigible aircraft as vessels of attack. Scouting is the primaryand indeed the only useful duty of the dirigible, although it isquite possible that the aerial craft might participate in asubsequent naval engagement, as, indeed, has been the case. Itsparticipation, however, would be governed entirely by climaticconditions. The fact that the dirigible is a weak unit of attackin naval operations is fully appreciated by all the belligerents.

The picture of a sky "black with Zeppelins" may appeal to thepopular imagination, and may induce the uninitiated to cherishthe belief that such an array would strike terror into the heartsof the foe, but the naval authorities are well aware that nomaterial advantage would accrue from such a force. In the firstplace they would constitute an ideal target for the enemy'svessels. They would be compelled to draw within range in orderto render their own attack effective, and promiscuous shootingfrom below would probably achieve the desired end. One or moreof the hostile aircraft would be hit within a short while. Suchdisasters would undoubtedly throw the aerial fleet intoconfusion, and possibly might interfere with the tacticaldevelopments of its own friends upon the water below.

The shells hurled from the Zeppelins would probably inflict butlittle damage upon the warships beneath. Let it be conceded thatthey weigh about 500 pounds, which is two-thirds of the weight ofthe projectile hurled from the Krupp 128-centimetre howitzer.Such a missile would have but little destructive effect ifdropped from a height of 1,000 feet. To achieve a resultcommensurate with that of the 28-centimetre howitzer the airshipwould have to launch the missile from a height of about 7,000feet. To take aim from such an altitude is impossible,especially at a rapidly moving target such as a battle-cruiser.

The fact must not be forgotten that Count Zeppelin himself hasexpressed the opinion, the result of careful and prolongedexperiments, that his craft is practically useless at a heightexceeding 5,000 feet. Another point must not be overlooked. Ina spirited naval engagement the combatants would speedily beobliterated from the view of those aloft by the thick pall ofsmoke--the combination of gun-fire and emission from the furnacesand a blind attack would be just as likely to damage friend asfoe.

Even if the aircraft ventured to descend as low as 5,000 feet itwould be faced with another adverse influence. The discharge ofthe heavy battleship guns would bring about such an agitation ofthe air above as to imperil the delicate equilibrium of anairship. Nor must one overlook the circumstance that in such anengagement the Zeppelins would become the prey of hostileaeroplanes. The latter, being swifter and nimbler, would harrythe cumbersome and slow-moving dirigible in the manner of a dogbaiting a bear to such a degree that the dirigible would becompelled to sheer off to secure ts own safety. Desperatebravery and grim determination may be magnificent physicalattributes, ut they would have to be superhuman to face thestinging recurrent attacks of mosquito-aeroplanes.

The limitations of the Zeppelin, and in fact of all dirigibleaircraft, were emphasised upon the occasion of the British aerialraid upon Cuxhaven. Two Zeppelins bravely put out to overwhelmthe cruisers and torpedo boats which accompanied and supportedthe British sea-planes, but when confronted with well-placedfiring from the guns of the vessels below they quickly decidedthat discretion was the better part of valour and drew off. Innaval operations the aeroplane is a far more formidable foe,although here again there are many limitations. The first andmost serious is the severely limited radius of action. Theaeroplane motor is a hungry engine, while the fuel capacity ofthe tank is restricted. The German military authorities speedilyrealised the significance of this factor and its bearing uponuseful operations, and forth with carried out elaborateendurance tests. In numerable flights were made with theexpress purpose of determining how long a machine could remain inthe air upon a single fuel supply.

The results of these flights were collated and the achievementsof each machine in this direction carefully analysed, a meanaverage drawn up, and then pigeon-holed. The results were keptsecret, only the more sensational records being published to theworld. As the policy of standardisation in the construction ofaeroplanes was adopted the radius of action of each type becameestablished. It is true that variations of this factor evenamong vessels exactly similar in every respect are inevitable,but it was possible to establish a reliable mean average forgeneral guidance.

The archives of the Berlin military department are crowded withfacts and figures relating to this particular essential, so thatthe radius of action, that is the mileage upon a single fuelcharge, of any class and type of machine may be ascertained in amoment. The consequence is that the military authorities areable to decide the type of aeroplane which is best suited to acertain projected task. According to the dossier in thepigeon-hole, wherein the results of the type are filed, theaeroplane will be able to go so far, and upon arriving at thatpoint will be able to accomplish so much work, and then be ableto return home. Consequently it is dispatched upon the especialduty without any feeling of uncertainty.

Unfortunately, these experimental processes were too methodicalto prove reliable. The endurance data were prepared from testscarried out in the aerodrome and from cross-country trialsaccomplished under ideal or fair-weather conditions. The resultis that calculations have been often upset somewhat rudely byweather conditions of a totally unexpected character, which bringhome vividly the striking difference between theory and practice.

The British and French aviation authorities have not adopted suchmethodical standardisation or rule of thumb inferences, butrather have fostered individual enterprise and initiative. Thisstimulation of research has been responsible for the creation ofa type of aeroplane specially adapted to naval service, andgenerically known as the water plane, the outstanding point ofdifference from the aeroplane being the substitution of canoes orfloats for the wheeled chassis peculiar to the land machine. Theflier is sturdily built, while the floats are suf ficientlysubstantial to support the craft upon the water in calm weather.Perhaps it was the insular situation of the British nation whichwas responsible for this trend of development, because so far asBritain is concerned the sea-going aeroplane is in dispensable. But the salient fact remains that to-day the waterplane serviceof Great Britain is the most efficient in the world, the craftbeing speedy, designed and built to meet the rough weatherconditions which are experienced around these islands, and idealvessels for patrol and raiding duties.

So far as the British practice is concerned the waterplane isdesigned to operate in conjunction with, and not apart from, theNavy. It has been made the eyes of the Navy in the strictestinterpretation of the term. In any such combination the greatdifficulty is the establishment of what may be termed a mobilebase, inasmuch as the waterplane must move with the fleet. Thisend has been achieved by the evolution of a means of carrying awaterplane upon, and launching it from, a battleship, ifnecessary.

For this purpose a docking cradle or way has been provided aftwhere the aeroplane may be housed until the moment arrives forits employment. Several vessels have been devoted to thisnursing duty and are known as parent ships to the waterplaneservice. All that is requisite when the time arrives for theuse of the seaplane is to lift it bodily by derrick or cranefrom its cradle and to lower it upon the water. It will beremembered that the American naval authorities made anexperiment with a scheme for directly launching the warplanefrom the deck of a battleship in the orthodox, as well asoffering it a spot upon which to alight upon returning from aflight, while Wing-Commander Samson, R.N., D.S.O., the famousBritish airman, repeated the experiment by flying from asimilar launching way installed upon H.M.S. Hibernia. Butthis practice has many shortcomings. So far as the Britishand French navies are concerned, the former process ispreferred. Again, when the waterplane returns from a flightit is admitted that it is simpler, quicker, and safer for itto settle upon the water near the parent ship and to be liftedon board.

As a sea-scout the waterplane is overwhelmingly superior tothe dirigible as events have conclusively proved. Itsgreater mobility and speed stand it in excellent steadbecause it is able to cover a larger area within a shorterspace of time than its huge and unwieldy contemporary.Furthermore, it is a difficult target to hit and accordinglyis not so likely to be brought down by hostile fire. Thereis another point in its favour. The experience of the warhas proved that the numerically inferior enemy prefers tocarry out his naval operations under the cover of the mistand haze which settle upon the water, and yet are ofsufficient depth to conceal his identity and composition.Such mists as a rule comprise a relatively thin bank oflow-lying vapour, which while enveloping the surface of thewater in an impenetrable pall, yet permits the mast-headsof the vessels to stand out clearly, although they cannotbe detected from the water-level or even from the controland fighting tops of a warship. A scouting waterplane,however, is able to observe them and note their movement,and accordingly can collect useful information concerningthe apparent composition of the hidden force, the course itis following, its travelling speed, and so forth, which itcan convey immediately to its friends.

The aeroplane has established its value in another manner.Coal-burning vessels when moving at any pronounced speedinvariably throw off large quantities of smoke, which maybe detected easily from above, even when the vesselsthemselves are completely hidden in the mist. It was thiscircumstance which revealed the presence of the Britishsquadron in the affair of the Bight of Heligoland.

The German airman on patrol duty from the adjacent base onthe island of Heligoland detected the presence of thissmoke, above the low-lying bank of fog, although there wereno other visible signs of any vessels. Fully cognisant ofthe fact that the German Fleet was at anchor in a safe placehe naturally divined that the smoke proceeded from a hostilesquadron, evidently bent upon a raid. He returned to hisheadquarters, conveyed the intelligence he had collected tohis superior officers, upon receipt of which a German cruisersquadron was sent out and engaged the British vessels to itsown discomfiture. But for the airman's vigilance and smartnessthere is no doubt that the British squadron would haveaccomplished a great coup.

This incident, however, served to reveal that the aerial scout isprone to suffer from over-keenness and to collect only a partialamount of information. Upon this occasion the German watchmandetected the presence of the British torpedo-boat and lightcruiser force. Had he continued his investigations and made awider sweep he would have discovered the proximity of the Britishbattle-cruiser squadron which routed the German force, the latterhaving acted on incomplete information.

While the low-lying sea-fog is the navigator's worst enemy, it isthe airman's greatest friend and protection. It not onlypreserves him against visual discovery from below, but is anexcellent insulator of sound, so that his whereabouts is notbetrayed by the noise of his motor. It is of in calculable valuein another way. When a fog prevails the sea is generally assmooth as the pro verbial mirror, enabling the waterplanes to bebrought up under cover to a suitable point from which they may bedispatched. Upon their release by climbing to a height of a fewhundred feet the airmen are able to reach a clear atmosphere,where by means of the compass it is possible to advance inapproximately the desired direction, safe from discovery frombelow owing to the fog. If they are "spotted" they can dive intoits friendly depths, complete their work, and make for the parentship.

Low-lying sea-fogs are favourable to aerial raids provided thescout is able to catch sight of the upper parts of landmarks toenable him to be sure of the correctness of his line of flight-incases where the distance is very short compass direction issufficiently reliable-because the bank of vapour not onlyconstitutes a perfect screen, but serves as a blanket to themotor exhaust, if not completely, at least sufficiently tomislead those below. Fogs, as every mariner will testify, playstrange tricks with the transmission of sound. Hence, althoughthose on the vessels below might detect a slight hum, it mightpossibly be so faint as to convey the impression that the aviatorwas miles away, when, as a matter of fact, he was directlyoverhead. This confusion arising from sound aberration is auseful protection in itself, as it tends to lure a naval forcelying in or moving through the fog into a false sense ofsecurity.

The development of the submarine revealed the incontrovertiblefact that this arm would play a prominent part in futureoperations upon the water: a presage which has been adequatelyfulfilled during the present conflict. The instinct ofself-preservation at once provoked a discussion of the mosteffective ways and means of disguising its whereabouts when ittravels submerged. To this end the German naval authoritiesconducted a series of elaborate and interesting experiments offthe island of Heligoland. As is well known, when one is directlyabove a stretch of shallow water, the bottom of the latter can beseen quite distinctly. Consequentiy, it was decided to employ aerial craft as detectives. Both the aeroplane and the dirigibletook part in these experiments, being flown at varying heights,while the submarine was maneouvred at different depths immediatelybelow. The sum of these investigations proved conclusively thata submarine may be detected from aloft when moving at a depth offrom 30 to 40 feet. The outline of the submerged craft iscertainly somewhat blurred, but nevertheless it is sufficientlydistinct to enable its identity to be determined really againstthe background or bottom of the sea. To combat this detectionfrom an aerial position it will be necessary inter alia to evolvea more harmonious or protective colour-scheme for the submarine.Their investigations were responsible for the inauguration of theelaborate German aerial patrol of harbours, the base for suchaerial operations being established upon the island ofHeligoland.

So far the stern test of war as applied to the science ofaeronautics has emphasised the fact that as a naval unit thedirigible is a complete failure. Whether experience will bringabout a modification of these views time alone will show, but itis certain that existing principles of design will have toundergo a radical revision to achieve any notable results. Theaeroplane alone has proved successful in this domain, and it isupon this type of aerial craft that dependence will have to beplaced.

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Chapter XVIII : AIRCRAFT AND NAVAL OPERATIONS

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