Blimp squadron was first line of defense against enemy subs, balloon bombs

The massive dirigibles were housed in the largest clear-span wood buildings in the world, near Tillamook; one burned in 1992, while the other houses the Tillamook Air Museum today.

By Finn J.D. John — May 21, 2011

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Just south of Tillamook, tucked into a deep-green valley surrounded by dairy farms, is the largest clear-span wood-frame building in the world.

This is Tillamook Naval Air Station Dirigible Hangar B, whipped together in just a few months during the early years of World War II. Its "world's largest" title is one it shares with several other dirigible hangars built on the same plans in other parts of the country at the same time; the hangar in Tillamook is the only one of these that's currently open to the public.

These hangars have a seven-acre footprint. They're 296 feet wide and 1,050 feet long — big enough for three football fields lined with bleachers on each side.

There's about 2.5 million board feet of gorgeous, clear, old-growth Douglas Fir in each one of them. Tillamook Hangar B was home to a squadron of eight military blimps.

The conventional wisdom is that those blimps arrived on the scene too late to have a real impact on the war — that by the time they were regularly patrolling the West Coast, in late 1943, the threat of Japanese attacks had passed.

But that isn't entirely true. In fact, we'll probably never really know the full extent to which the Oregon-based blimp fleet prevented attacks on the West Coast. But it's a good bet that if they'd been suddenly grounded in, say, the summer of 1944, we would have noticed, and some people might have actually been killed.

Here's the story:

Vulnerable to Japanese submarines

During the years just before World War II, the U.S. was getting increasingly nervous about Nazi and Imperial Japanese submarine fleets. It was hard to imagine a fleet of surface warships skulking unnoticed across the Atlantic Ocean to attack the U.S., but a submarine could do just that — and lurk there, waiting for prey to steam by, for months on end.

Regular airplanes were OK against subs, but couldn't stay in the air for very long and didn't have the ability to hover over a convoy all day.

Blimps, though — blimps were perfect. Their main drawback was that they were huge and easy for aircraft to shoot down. But for defending shipping near the U.S. mainland, enemy aircraft were not a problem.

So the Navy got started building a network of 17 massive blimp hangars at strategic and sheltered locations around the coastline.

To cover the area of the West Coast from Seattle down to northern California, the Navy built two of these massive hangars at Tillamook.

About the airships

The airships they put in them were Goodyear K-class soft-sided blimps 216 feet long, filled with helium rather than hydrogen. They moved at a maximum speed of roughly 70 miles per hour, had a range of 2,000 miles and could float around for up to three days, looking straight down into the sea in search of the shadowy outline of a submarine. If they found one, they had four depth-charge bombs on board with which to do something about it, and of course the ability to contact other Navy assets — bombers, warships, etc. — as well. They also carried a pair of .50-caliber machine guns because of course they did — the U.S. military put a pair of "deuces" on everything in World War II.

Off the East Coast, protecting convoys againt Nazi subs, the blimps had a substantial effect —although they sank few if any U-boats. The presence of a blimp over a convoy was usually enough to prevent an attack on it; a submarine at torpedo depth was easy to spot, especially on a sunny day, and nothing wrecks a gunner's concentration like a well-placed depth charge.

But the West Coast was only visited by 10 Japanese submarines, most of them early in the war, before the squadron was up to speed. By the time blimp patrols were happening regularly, Japan had pulled its subs back to help defend its other naval assets from an increasingly overwhelming American Pacific fleet.

So in the west, the conventional wisdom for a long time has been that the blimps just flew patrols, looking for something that wasn't there but might arrive at any time, for the remainder of the war. But it turns out they did other things as well.

Japan's scheme to start forest fires

Japan had a desperate plan, late in the war, to light the forests of Oregon and Washington on fire. To do this, they launched unmanned balloons with incendiary bombs on the prevailing winds to be carried across the sea; after the amount of time they calculated it would take them to drift across the Pacific Ocean, the balloons would deflate, fall to the ground and explode, torching the surrounding forest. If a bomb fell in a West Coast town, so much the better, as the casualties and the fear of future attacks would undermine American morale — or so the theory went.

(By the way, here's a link to an excellent and thorough account of the balloon-bomb program — in particular the role played by American geologists in identifying the exact part of Japan from which the bombs came, so that B-29s could strike back — by Prof. J. David Rogers of Missouri University of Science and Technology. And did you know one of the bombs is suspected of having started the 1945 Tillamook Burn? More info is right here.)

The Japanese launched almost 10,000 of these balloons in late 1944 and early 1945. About 300 of them reportedly made it through. Fighter planes were helpful but the balloons rode the air currents very high up — around 35,000 feet, more than six miles. Getting airplanes off the ground and up that high in the air could take as long as an hour and burn plenty of fuel, leaving little time to fly around looking for bombs before having to return to the airfield.

Enter the blimp fleet.

Blimps vs. balloons

We'll probably never know how many balloons blimps knocked out of the sky with their machine guns. The U.S. government was keeping a lid on the whole thing, hoping the lack of hubbub would convince the Japanese that their balloon program wasn't working — a strategy that worked nicely, as it turns out. But we do know that at least one blimp operating out of Tillamook was assigned to search out and intercept these.

So the squadron at Tillamook may not have seen much action against submarines, but it's possible that they saved the U.S. from something even more dangerous.

End of the line for the airships

At the end of the war, the Navy was a lot less worried about having to defend the U.S. mainland, which was all the blimps were really useful for. By 1948, the Navy had decided to close the Tillamook station down; the county leased (and later bought) the place to run as an airport. The hangars were used for a variety of things — civilian blimp tours, a lumber mill, balloon testing and even aircraft manufacturing.

A massive fire demolished one of the Tillamook blimp hangars in 1992 after somebody at the county decided it would be OK to let a local farmer store hay in it. Today, the surviving hangar is home to the Tillamook Air Museum, which features a huge collection of vintage aircraft and memorabilia.

(Sources: Naval Air Station Tillamook Historical Society, www.nastillamook.org; Naval Airship Association Inc., www.naval-airships.org; Tillamook Air Museum, www.tillamookair.com; U.S. National Park Service, www.nps.gov/history/nr)

TAGS: #TillamookHangar #Blimps #GoodyearKclass #WorldsLargest #ImperialJapan #Submarines #BalloonBombs #TillamookAirMuseum #Airships #COAST #TILLAMOOKcounty

 

 

 

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