American Scouting Perimeter: The Class B Mooring Bases

Like the German rigids before and during WWI, on USS Shenandoah’s first cross-country trip, the airship was held on the St. Louis Air Race grounds by crews without mooring facilities.  Concrete block-mounted eye rings anchored British rigid R.34 while at its Long Island stopover, barely visible in our video, using the early British “3-wire” system invented for operating bases. The British were first to develop the “tower” mast. Its design height came from the thinking that a “high” mast was better for the airship, which could be more safely moored and “flown” at the mast across a variety of wind and weather conditions.

Similar in theory to early British masts, semi-portable 160-foot tall mooring masts were built by the US Navy in time for ZR-1’s first trip to California.

 

The masts, which could be partially dismantled, transported and re-erected, consisted of three distinct risers and were braced by cables to deadmen anchors (excavations filled with concrete) at a 500-foot radius around the mast. This circle of twenty-four snatch block anchorages were spaced at fifteen degree intervals (Ewa, photos and diagrams).

A sixteen -inch spar of steel tubing, bolted to and supported by a concrete base, carried the mooring cable. A climbing trunk, gassing main, electrical power, water and fuel lines extended to the top platform.

A machinery shed near the base (arrow in photo, left) contained winches, pumps and other equipment for servicing the airship, similar to that found in the base of Scott Field’s tower mast (photo, right). Fuel and water tanks were nearby.

At the top of the masts were operating platforms for the crews monitoring the mooring mechanism. A hollow “flower pot” mooring cone, identical to the corresponding receiver on the Lakehurst tower mast, was mounted atop a flexible extension that carried the mooring cable. Once the airship’s “plum bob” mooring cone was locked in the cup, the moored airship was at the right height to open its bow door to the platform.

The photo shows RADM Moffett and LCDR Landsdowne riding the adapted balloon basket at the San Diego mast. An auxiliary winch pulled the basket (arrow) to the small landing platform (star) just below the wider platform that allowed access to the airship’s bow door.  Note the available signal flags and pendants tied on the cable stays for safety at North Island, an active Army and Navy airplane field. Larger, heavier provisions would not have to be hauled up more than 150 feet of ladder.

Roughly identical masts and their machinery sheds were erected at Fort Worth, Texas (near the helium plant), San Diego (North Island), California, Ewa, Hawaii, and Camp (Fort) Lewis, Washington. The literature does not specify how much of the portable equipment, such as what might be a yaw- line winch-car shown in this photo, were permanently assigned or traveled with the airship ground troupe.

The Shenandoah used the Fort Worth mast on two occasions, flying to and from California. ZR-1 also used the San Diego mast on the same two missions.  The Camp (Fort) Lewis mast was used only once, on the “rim of America” flight. The USS Los Angeles also moored to the Fort Worth mast on one occasion, in 1928. A planned Hawaii trip by the ZR-1 was made impossible by her loss in 1925.

Following the incidents of the ZR-1’s breakaway and of the ZR-3’s famous near nose-stand on the “high” or “tower,” mast,  and the British abandoning its series of tower masts around the Empire, engineering philosophy turned to solutions closer to ground level. Not only was it easier to service the airship, and over-ballasting would eliminate kiting incidents, but also no crew had to stand 24/7 elevator watch.  Several interim masts and facilities are detailed in Ground Handling Evolution.

A low mast was constructed at NAS Lakehurst (photo) even before its tower mast was torn down.  A tamped-earth circle was engineered to intersect with a taxi wheel dolly mounted below the engine #1 car.  Reinforced with ground-equipment girders not meant to fly (but did, locally) the airship could weathervane in the wind indefinitely. The photo shows a late, mature version of this riding-out car with its handlers’ extension handles, which featured their own suspension. An additional mooring mast 60 feet in height was erected inside the Marine Corps base at Paris Island, South Carolina. The ZR-3 rode the 438-foot radius mooring circle.

More resources had been expended for ground handling facilities as the ZRS program moved toward delivery, and similar improvements trickled down to secondary facilities. At Lakehurst, railroad track was laid around the former tamped-earth circle, and as seen in the photo, left. A riding-out car was built to saddle the ZR-3 lower engine gondola, right photo. Appearing to be simple railroad-like wheels, the cars actually gripped the track with clamps that positively prevented kiting. A similar track of 438-foot radius was constructed at Fisherman’s Point, Guantanamo, Cuba, the ZR-3 riding its circle (center photo) during several Caribbean exercises.

To support the ZRS ships’ probable deployment around the American “empire,” six “Class B” (auxiliary) rigid airship bases were established by improving some sites and building others anew. The Paris Island mast was extended to 75 feet and a new tamped circle of 643 feet was compacted. In Cuba, a railroad mooring circle of 643 feet radius was added to McCalla Field. (ZRS-4 masted at Parris Island once, but only overflew the Cuba site, without mooring.)  The Camp Lewis, Washington mast was still at 160 feet when ZRS-4 overflew the site. Though Lewis was later lowered, no rigid airship ever moored there again.

Photographs support the record that the San Diego high mast and machine sheds were re-engineered and relocated to Camp Kearney (near San Diego) for the USS Akron In 1932. Shipped in from Lakehurst, the airship’s added lower fin taxi wheel also rode on a tamped-earth circle. Photos show the mast had been simplified, and its anchor block circle was much smaller. The climbing guard cage had been eliminated, and with it the adapted balloon basket with its winch.

 On that same west coast trip ZRS-4 rode the railroad circle laid out at the Sunnyvale construction site (photo). Learning the lessons of Lakehurst, the hangar had been laid out with the prevailing winds, so only one permanent mooring-out circle would be needed.  The Bettinger boy photo (extreme right) shows the riding-out car carrying the Akron’s lower fin bumper bag, which would be attached for flight.

Early in 1932 the City of Miami offered one square mile of Florida pine scrub to the Navy, which became the Opa-Locka Class B Operations base.  The Mare Island Navy Yard in California supplied the 75-foot mast and a 643-foot radius mooring circle of railroad tracks was constructed for the lower fin ride-out car. When the LZ-127 visited in 1933 the mast was an awkward but workable fit, as the photos show. In the Gibbens boys photo (extreme right) the Akron’s riding out car is barley visible. (The Gibbens home movie of their Macon Opa-Locka visit is included in our DVD The Flying Carriers.)

The more logical west coast airship master base location, San Diego, next door the main fleet harbor, would at least be upgraded to Class B standard as a railroad circle with a radius of 643 feet was added around the Camp Kearney mast. The photos show several improvements to the mast and site as Macon is moored one of the four times it used the base without incident.

In the film made by Navy photographer Carroll, the yaw winch car seen riding the mooring rail circle is noted to be at Camp Kearney. It is likely the units at other Class B sites were similar to those at Moffett.

Available photos of Ewa illustrate the measures taken to upgrade the site to Class B status.  A heavier mooring cable was employed, the images showing its path inside the mast, around its base pulley, and onto the drum guided by the back-and-forth spooling mechanism.

Less visible is the rail track and very rare are photos of the equipment that rode on the track. (Rail sections from the Ewa track [below] were still visible on the Barbers Point golf course in 2019.)  The 643-foot railroad track, its ride-out car, the yaw winch cars, the winch sheds and the rest of the Ewa base were still awaiting for a rigid airship when the US Marines were assigned the area for an airplane field. The mooring mast was repurposed into a tower for the air controllers.

Still available for airships in January 1941, Ewa’s LTA contingent featured a few out buildings and one small house for the Chief Petty Officer in charge, his family, and three enlisted men. This status existed on 7 December 1941 when the field was heavily bombed during the attack on Pearl Harbor. Of the forty-eight airplanes of Marine Air Group 21 on the field at Ewa, thirty-three were destroyed and all but one of the remaining fifteen suffered major damage.

In the ZRS movie universe,  since Macon had its fin reinforcements in place before the Fleet exercise in February of 1935, she continued with its planned deployment to Hawaii in March. (The diagram shows the facility layout plan and the overall appearance would have been similar to Camp Kearny, photo.)

Five years later, in the novel’s timeline, Macon would have been a seasoned hand with distant Pacific searches all around Hawaii. So of course, like the actual barrage balloons that were not deployed to protect battleship row, Macon would have been on the mast that Sunday morning. The Japanese planes that attacked the Ewa Marine airfield on December 7th would have destroyed Macon had she been moored there. 

With Macon’s wreck fouling the site, USS Long Island is forced to return to Sunnyvale for repairs following her Japanese encounter.

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