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Forgotten Weapon: U.S. Navy Airships and the U-Boat War

by William F. Althoff, Naval Institute Press, Annapolis, Md., 2009, $49.95.

It’s rare for a new book to appear describing an aspect of World War II that hasn’t already been covered in great detail elsewhere, but that is precisely the case in Forgotten Weapon. The development and contribution of U.S. Navy LTA (lighter-than-air) aviation to the war effort has been almost completely overlooked in favor of carrier-based, land-based and water-based airplanes. Yet LTA was involved from the beginning, overcoming great handicaps to become a major component of naval operations and a formidable weapon in combating the scourge of German U-boats.

During the 1920s and 1930s, the Navy concentrated primarily on the development of large, rigid airships. They were meant to operate in conjunction with the fleet as very long-range reconnaissance units, much like air borne cruisers. As happened in other countries, however, the Navy’s rigid airships proved to be expensive, fragile and dangerous to operate. Most ended their days in spectacular disasters, engendering a negative perception of lighter-than-air aviation in general.

Yet the huge airships were not the only component of LTA. There were also the smaller, nonrigid airships popularly known as “blimps.” Unlike rigid airships, blimps didn’t tend to break apart in bad weather. They also had a proven record of effectiveness as antisubmarine platforms with the Royal Navy during World War I.

Nevertheless, the Navy’s LTA program had languished since 1935, when the last of its big rigid airships, USS Macon, crashed into the Pacific. By 1937 the entire Navy LTA program was down to just three blimps operating out of a single base, with a total personnel roster equivalent to the crew of a destroyer. Worse, Navy rules stipulated that a new LTA pilot could only qualify after he had accrued a number of hours in rigid airships. Since the Navy no longer had any rigid airships, it was impossible for new LTA pilots to qualify. Despite the sorry state of LTA in the late 1930s, by the end of WWII the Navy had 165 blimps, deployed in 14 squadrons distributed among five fleet airship wings.

Blimps were employed primarily in an antisubmarine role, patrolling offshore and escorting merchant ship convoys. Although they operated largely out of the public eye, they proved to be invaluable in the campaign. Unlike with their heavier-than-air counterparts, the value of the blimps cannot be measured in tons of bombs dropped, aircraft shot down or even numbers of U-boats sunk. William Althoff describes in detail numerous occasions when blimps assisted surface vessels or fixed-wing aircraft in locating and destroying enemy subs without actually sinking U-boats themselves. More often than not the mere presence of a blimp over a convoy discouraged U-boats from attacking, and Althoff explains how they frequently remained on station despite bad weather or poor visibility that grounded fixed-wing aircraft.

The airships were armed primarily with depth charges and .50-caliber machine guns. But Althoff also details many new technological advances with which they were equipped, such as radar, loran electronic navigation, magnetic anomaly detection (MAD) equipment and sonobuoys. In addition, he describes a lethal, top-secret weapon deployed from blimps that has hitherto received almost no mention—an early type of acoustic homing torpedo.

Forgotten Weapon is a magnificent memorial to a branch of the armed forces that truly has been forgotten. Its publication heralds a reappraisal of the Navy’s wartime LTA program that has been long overdue.


Originally published in the May 2010 issue of Aviation History. To subscribe, click here.