AIR TORPEDO REVISES WARSHIP QUESTION

Manawatu Times, Volume 66, Issue 209, 3 September 1941, Page 8

AIR TORPEDO REVISES WARSHIP QUESTION

Lesons From Sinking of Bismarck Disclosure of the vital role played by torpedo planes iu the ‘ 1 battle of the Bismarck” is one of the significant contributions to the arguments between sea power and air power (writos Captain F. L. Oliver, a leading American naval expert). But totalling up the evidence in tho air-sea conflict so far, tho experience does not support the claims advanced by those proponents of aircraft who definitely assert that men-of-war with- j out distinction as to class, are done fo> Authoritative naval opinion continues to place reliance on the surface ship, especially tho battleship. However, this has become modified by some very important reservations. The Norwegian campaign, and the recent melee in the vicinity of Crete, as well as other less publicised instances, very definitely prove that the lighter types of men-of-war aro as vulnerable to airplane attack as are merchantmen, provided £he conditions favour the plane. Analysis of Situation Conditions favourable to air attack may be generalised as: 1. Ships being within easy bombing flight of airfields—that is, open to attack by shore-based planes. 2. A large number of available airplanes. 3. Suitable weather, especially cloud formations which hide planes until they are ready to strike. 4. Absence of defending aircraft. 5. Ships with inadequate or damaged anti-aircraft defence, or whose speeds and/or manoeuvring qualities have been impaired. 6. Ships operating in confined waters. Odds Must Be Weighed In the vicinity of Crete conditions, except possibly, that of . cloud forma’tions, -were distinctly, favourable to the airplane, and many British cruisers, destroyers, and other light craft were destroyed by Nazi bombs, but this in no way can bo considered to prove the case for the airplane. A handful of British ships, unsupported by own aircraft, attempted a nautical version of “The Charge of the Light Brigade” against overwhelming odds and came out second best. In this encounter huge waves of Nazi planes aro reporteu to have been thrown into the attack without regard j to losses, with the result that the Brit- j ish defence was -overcome. The same result could have been attained had an overpowering attack been made by sur- j face vessels. No battleship has been sunk toy i bombs, although extensive structural. 1 damage has been sustained in a num- j her of instances. However, battleships , have succumbed to aeroplanes which attacked with torpedoes, notably the Italian battleships sunk at Taranto. Tho Bismarck is reported to have been slowed down by one torpedo, attack and to have been made unmanageable by a. subsequent plane-; launched torpedo which disabled the battleship’s propellers and rudder. Tile result was that the Bismarck became an easy target for gunfire and other torpedoes. More recently the British claim that a torpedo plane seriously damaged a German pocket battleship in Norwegian waters. Concentrated Sea Power. But it must bo recalled that the airborne torpedo attacks against the Bismarck were from tw-o aircraft-carriers. These are vulnerable ships and must be adequately protected. That they were available to the British for use against tho Bismarck was nothing new in naval strategy It was the familiar concentration of sea power to overwhelm an enemy. I It may bo asked why the j)la.necarried torpedo is effective againsl the. battleship, whereas the bomb does relatively little damage. The answer is that torpedoes attack tho vital unarmoured under-water structure, whilo bombs are unable to reach vital interior areas because they cannot penctrato the heavy armoured decks.

There are two types of aeroplane bombing—level flight and dive-bomb-ing. The former has proved to be relatively inefficient against na\**l vessels because tho latters anti-air shell guns keep the planes at such high altitudes that bomb hits are seldom made. Most of the bomb damage has been dono by the Stuka or dive-bombers. This type of attack, which originated | with the air arm of the United States Navy in 1924, has been extensively! used by the Germans both at s7a and on shore.

Dives at Great Speed. As the name implies, the plane dives more directly toward the target at vemendous speed from an altitude of 20,000 or more feet. It is very difficult to hit, and foi; this reason it can release its bombs at the comparatively low altitude of some 2000 feet, with resultant incrcaso in accuracy.

The shell gun is too cumbersome for efficient use against the dive-bomber, but multiple mounted heavy machineguns can do deadly execution if they van be brought into action in sufficient time. However, a dive-bomber emerging from the shelter of low-hanging clouds is a target for a very brief period of time, and frequently- is able to drive its attack home.

Bombs aro ineffective against a heavy armoured deck because they lack sufficient striking velocity to pierce ’The deck before the thin-walled container shatters. When released in a level attack, bombs have a zero initial velocity, and those from dive-bombers have a velocity no greater than the vertical component of the plane’s speed, which for a 300-mile-an-liour plane would roughly be about one-fifth the muzzle velocity of a shell fired from a gun.

Theoretically the terminal velocity of a /ailing bomb would be a function of the distance through which it is acted on by tho force of gravity, and the greater the height at which it is released the greater the striking velocity.

However, such a result obtains only in a vacuum, because the friction set up by the earth’s atmosphere comes into play, with the result that a bomb never attains a velocity greater than about 900 feet a second.

Emphasis on Weight. Because of this inherent quality of the bomb, it has been developed as a thin-walled container, emphasis being placed on the weight of explosive. A , missile of this type explodes- when it > brings up on a deck it cannot penetrate. Attempts have been made to develop an armour-piercing bomb .by reducing ; the weight of the charge and using a ; heavier walled container of special alloy steel, but it is understood that a - good five to six inch deck will withstand their low velocity attack. To insure , penetration, the bomb will have to ] approach a gun shell in structural j strength, thereby sacrificing weight of t

gratifying. charge with resultant decrease in destructive effect. Except in coastal waters where command of the air has been attained, the superiority of tho plaue over the surface ship has not yet been demonstrated. Anti-air batteries of surface ships are continually being augmented by new and superior types of guns and fire control, and in the open sea beyond the reach of planes operating in strength from shore bases, the surface ship continues to hold its own.