What do a mature tree and a twenty-foot cargo container have in common? In the 1970s, you could carry both away by balloon. Balloon logging, as the practice was known, had a successful niche in the West Coast forestry industry for a few decades. Cargo handling by balloon, on the other hand, was tested by the US military but never made it out of the experimental stage
Two realizations were behind the US military experiments with cargo handling by balloon. The first was that the US was grossly under-equipped to handle military cargo in large quantities anywhere other than a well-equipped modern part. The second was that the international shipping business was becoming more and more reliant on moving materials in standardized cargo containers and that what equipment the US military did have was not designed to handle containerized cargo. Experiments with mobile cranes, helicopters, hovercraft, and floating piers were all part of the search for solutions to these two problems.
Among the more radical experiments were a series of tests that used helium balloons to unload cargo containers from a container ship anchored offshore. Inspiration for what became Joint Army/Navy Balloon Transport System came from Oregon and Washington, where loggers had been reaching further and further into the backcountry by developing new ways to move felled trees. In the 1920s groundlead yarding, where a long line powered by a steam engine skidded the logs along the ground, was replaced by high-lead yarding, where the lines were strung from a tall spar tree and the logs moved through the air rather than along the ground. High-lead yarding was limited by the need to find an appropriate spar tree, but lifting logs by balloon would let loggers shift logs even where the ground was too rough and the distances too long to use high leads. Tests started in Sweden in 1956, then in Canada in 1963 with Second World War-surplus barrage balloons. In the US, Goodyear Aerospace did some early experiments but it was Raven Industries that became the main supplier to the industry in the Pacific Northwest in the late 1960s.
In 1972, the Advance Research Projects Agency took notice. ARPA was the military’s high-tech incubator – later than year it would pick up the prefix “Defense” and gain its current acronym, DARPA. It hosted a conference with balloon-builders at Raven Industries to brief military officials on the possibility of using their logging balloons to lift containerized cargo. The Air Force Range Measurements Laboratory, which was already using balloons to carry instrument packages, was roped in to provide technical expertise.
For Raven, offering balloons to the military brought the company back to its roots. Founded in 1956 by staff from General Mills’s High Altitude Research Division, including the “father of hot air ballooning,” Ed Yost, Raven began its business with contracts from the Office of Naval Research to build experimental balloons. Expanding from balloons into plastics, electronics, and sewn goods, the company secured millions of dollars of military contracts for radios and other electronics.
Borrowing balloons and working crews from Raven Industries and the Bohemia Lumber Company, the Air Force flew cargo containers 1500 feet across a ravine in Culp Creek, Oregon. Returning to Culp Creek five months later, they tested the balloon’s ability to lift and move containers from a simulated ship’s cargo cell, as well as the use of a third winch (a “flying Dutchman”) to shift the balloon not just along one axis but laterally as well. Extrapolating from the 1500 foot tests they calculated that a balloon could move nine containers every hour from up to a mile offshore. Finally, the laboratory towed the balloon along a track to test its reaction to wind speeds of up to 30 knots.
In 1976, the balloon graduated to sea tests off Virginia Beach. Now given the moniker of Joint Army/Navy Balloon Transport System, a logging balloon was used to lift cargo containers from a simulated container cell on a Navy LST and deposit them either aboard a nearby landing craft or on the beach 700 yards away. Though it took about four times as long as the ideal calculations had suggested, the balloon was able to do the job. Ships shifting at anchor also required repeated stops to re-position the balloon.
The next year, a commercial company halfway around the world proved that the idea of unloading cargo by balloon wasn’t a fantasy. Operated by the Yemen Skyhook Company, the balloon “Queen of Sheba” was used to unload 800 tons of cargo a day from vessels in the congested Yemeni port of Hodeida. That example, though, was not enough to overcome the mediocre signals from the Virginia Beach tests. 1976 was the height point for balloon-based ship unloading in the US.
Though the Navy had experimented with a variety of unloading techniques, they finally opted for one of the less dramatic solutions on offer. Ten existing container ships were refitted to carry two or three powerful cranes each. These auxiliary crane ships could substitute for cargo cranes aboard the containership or a port, letting the Navy use the rest of its lighterage and cargo-handling equipment as is. Though the crane ships have spent most of their time in reserve, every once in a while they are called into action to support large US operations. Five were sent to the Persian Gulf in 1991 and two went to Haiti after the 2010 earthquake to help unload relief supplies. Balloon logging, on the other hand, has kept going in various places, albeit as a specialized practice rather than a widespread innovation.
Source Notes: The USDA Yearbook of Agriculture describes the origins of balloon logging here; the Forest History Society discusses balloon logging on their blog; the military experiments are summarized in detail in a Naval Postgraduate School thesis here.