ALLIED AIRCRAFT USEFUL AGAINST U-BOATS.

Pukekohe & Waiuku Times, Volume 6, Issue 288, 29 June 1917, Page 2 (Supplement)

ALLIED AIRCRAFT USEFUL AGAINST U-BOATS.

EFFICIENT AS "SPOTTERS" FOR DESTROYER FLOTILLAS, By C. G,. GREY, Editor of the "Aeroplane," London. Sundry officers of the Royal Naval Air Service having been awardt'd decorations) for the destruction of submarines, it is presumably permissible to state openly that aircraft have been and are being used for the purpose or submarine catching. In fact, I have myself been permitted to tell in print certain R.N.A.S. yarns of adventures with submarines, so perhaps one may be .iurther permitted by a- benign censorship to discuss* the possibilities of aircraft still further. There is a popular illusion, which s not exactly a delusion, that the observer in an aeroplane can see as far down into the water as a submarine is likely to dive. Up to a point this k true, for if the water is clear it is possible to see some twenty or thirty feet into it from a point vertically above, and if such water is only' forty or fifty feet deep a submarine is not likely to dive beyond the visibility point. It is quite another matter, however, in the North Sea, where the water i-i ft kind of leaden grey in colour and where ten feet of water over the periscope is enough to hide a submarine as effectually as if she were twenty fathoms down. Therefore it is fairly obvious that the scouting aircraft have to depend on surface vision quite as much as the patrol boats. Where the Difference does come in is in the angle of vision from which that surface view is obfefined.

BETTER ANGLE OF VISION. For instance, a patrol boat might well miss seeing a periscope half a mile away, especially if the periscope were between the boat and the sun, so that the reflection of the sun off the water waw dazzling the lookout men. The aircraft observer, on the other hand, perched up aloft, would have a far better chance. The periscope, cutting through the water, makes a very distinct "wake," which spreads out on each side, no tbaft it makes a light but quite distinct "broad arrow" of foam. ?>

When the periscope is above water the top of the conning tower is not far below, so that this also 15 visible unless there is a heavy (breaking sea. And probably the bubbles from the exhausting air can also be seen.

Thin an escort of seaplanes or of the little S.S. type (or submarine scout) airships whioh are so familar to all seafaring people round the British leles should have a far better chance of spotting the presence of Submarines than could any escort of sur face ships. At the lame time it is well to remember that an escort of " destroyers" or some simlar type of armed' ship is necessary, because the aeroplane or airship of today is not capable of carrying guns big enough to sink submarines with certainty, and the airt of bomb-dropping from aircraft has not become sufficiently a science to make the certainty of a shell from a four-inch gun doing so. Therefore the aircraft by ..themselves can only hope to keep the submarines submerged by dropping .bombs at them, though "they may sink one here and there by a combination of personal &kill and good luck, whereas by acting as "ilpotters" for the highly-trained gunners of our destroyer flotillas they can co-operate very materially in the actual destruction of enemy Submarines. COVER VAST AREA.

Where the naval aircraft really do come in is in the immense surface of seal which they can cover in a very short time, and their ability to take enemy submarines by surprise while lying on the surface " airing" themselves and charging up their batteries. A small, fast scouting aeroplane does any thing between 80"and 100 mile ■ an hour, and at a height of 7000 or 8000 feet it is fairly hard to see. On land ■one is generally warned of an aeroplane's arrival by the sound of its engines; but at sea the lapping of the water an dthe whistling of the wind through tne rigging or round superstructure drown the sound of the aero engine till it is fairly close. Consequently a seaplane has more than a sporting chance of getting within a mile or so of a .submarine before it is seen, and if it gets within that distance it should be able to make things very unpleasant for the submarine, even if it has not the.luck to sink it outright. A really -big fleet of fast aeroplanes patrolling the routes followed by trade shipping, and taking aboard their supplies of Jjombs and fuel from mother ships, of the class officially known as "seaplane carriers," should be able to do a great deal toward keeping all sublines well under water during all daylight, and one seaplane carrier, with half a dozen efficient seaplanes operating therefrom, ought to be able to act by itself as an effective convoy lor a flotilla of half a dozen ocean- going | tramp steamers, even through waters i which were known to be fairly full of enemy submarines. SEAPLANE SEARCHLIGHT. Even at night, in moderately fair weather, which is naturally the best for submarine operations, big seaplanes with searchlights could do much to keep submarines under water, and so add to their troubles by preventing them from stopping on the surface long enough to air their interiors and to charge their storage batteries.

Neutral shippers travelling up and flown the Xorth Sea have doubtless met hig British flying boats at one time or another all over its rrea, so perhaps one may state definitely that already these big boats patrol regularly from the east coast of England to the Dutch coast, near where it joins the German coast. It only needs an extension of such patrol systems to make life on the surface very unpleasant for enemy submarines

Curiously enough, these big flying boats originated in America, and if Aiiieri-a. is seriously perturbed about the fate of American shipping and American citizens travelling by sea in the vicinity of Europe, it should not he ;.i difficult matter for America, to rig up in a very short space of lime unite a fleet of se.aplane carriers suitable for the handling of these big seaplanes. If eacli seaplane ship were armed v . ith gun- having a range of between five and ten mile', and if the gunners were practised in co-oper iting with aeropl um spotters, such ships ought to be the best poss'ilbe insurance f or American lives and goods on the high -ea.s.