Skip bombing



Skip bombing was a low-level bombing technique independently invented in several great powers between the World Wars. After Pearl Harbor (December 1941), it was used prominently against Imperial Japanese Navy warships and transports by Major William Benn of the 63rd Squadron, 43rd Bomb Group (Heavy), Fifth Air Force, United States Army Air Forces in the Southwest Pacific area theater during World War II. General George Kenney has been credited with being the first to use skip bombing with the U.S. Air Force.

Technique
The bombing aircraft flew at very low altitudes (200 - 250 ft) at speeds from 200 - 250 mph. They would release a "stick" of two to four bombs, usually 500 lb or 1000 lb bombs preferably equipped with four- to five-second time delay fuses from the side of the target ship. The bombs would "skip" over the surface of the water in a manner similar to stone skipping and either bounce into the side of the ship and detonate, submerge and explode next to the ship, or bounce over the target and miss. Unlike "Upkeep" or "Highball", this technique used standard types, although only bombs with a round nose would bounce off the water surface properly.

A similar technique was mast-height bombing, in which bombers would approach the target at low altitude, 200 to 500 ft, at about 265 to 275 mph, and then drop down to mast height, 10 to 15 ft at about 600 yd from the target. They would release their bombs at around 300 yd, aiming directly at the side of the ship. The two techniques were not mutually exclusive: a bomber could drop two bombs, skipping the first and launching the second at mast height. Practice missions were carried out against the SS Pruth, a liner that had run aground in 1923. The Battle of the Bismarck Sea would demonstrate that this was the more successful of the two tactics.

Aircraft
Various aircraft types were used for skip-bombing attacks, including B-17 Flying Fortress heavy bombers, B-25 Mitchell medium bombers, and A-20 Havoc attack bombers. These were supported by heavily armed Royal Australian Air Force Bristol Beaufighters, which would suppress Japanese antiaircraft fire with their machine guns and cannon. The Soviets used lend-leased A-20 Havocs and P-40 Tomahawks as well as Il-2 Shturmoviks (also used for air defence suppression). Skip bombers were often used by aviation of the Soviet Northern Fleet in combination with torpedo bombers (usually the same A-20 aircraft, skip bomber and torpedo bomber operated in pairs). Skip bombers were called "topmachtoviks" (топмачтовики) in Russian, because they were flying "at the level of ship mast tops".

Advantages and disadvantages
Skip bombing carried several advantages. Unguided, unpowered bombs are vastly cheaper than torpedoes of equivalent explosive power. Torpedoes take up to several minutes to reach their targets after launch, enough time for an agile ship with an attentive crew to turn and avoid the attack or minimize its damage; skipped bombs, however, reach their targets in seconds. Skip bombing is additionally carried out at high speeds, increasing bombers' chances of surviving anti-aircraft fire as aerial torpedoes of the era were dropped at relatively low speeds.

The main drawback of skip bombing was that it took a great deal of skill to perfect; sometimes the bombs would detonate too soon, or in some cases, sink too deep before its delay-fused explosion.

History
The first time skip bombing was used in action by U.S. pilots was at the base of Rabaul on New Britain. The United States 5th Army Air Force used B-25 bombers to attack and destroy Japanese ships. It proved to be a highly effective method and received growing popularity.

A notable use of this technique was during the Battle of the Bismarck Sea (March 2–4, 1943), off the northern coast of New Guinea.

Literature

 * Wawrzynski, Moroslaw (2005), Ju 87 in Foreign Service. Mushroom Model Magazine Special Red Series. ISBN 83-89450-17-8.
 * Murphy, James T. (1993), Skip Bombing. Praeger Publishers. ISBN 0-275-94540-5.
 * Resume of Skip Bombing. Transcription (imperfect) of 1943 AAF document. 43rd Bomb Group (H), 5th AAF website. Retrieved 8 August 2010.
 * Development of Skip Bombing. 43rd Bomb Group (H), 5th AAF website. Retrieved 8 August 2010.
 * "Skip Bombing With Logs" (1944). The Jungle Air Force of World War II 1942 - 1945. Retrieved 8 August 2010.