USS Macon: Miss-stepping to a Premature Burial

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By early February 1935 USS Macon (colorized photo above) and her LTA-HTA hybrid crew were at peak competency and ready for her long-awaited trial to scout in the open Pacific. At last, it seemed the mast base at Ewa, Hawaii, erected in the ZR-1 days, then lowered and track-equipped but still never used, would help fulfill the original object of the long-range, “blue-water” scout for the fleet. Operating from that mast, a potential Pearl Harbor attacker approaching anywhere within hundreds of miles of track width could be spotted from a thousand or more miles out in the Pacific – at a greater range than even one-way attack carrier airplanes.

20160725_092040However, back east a controversy that had started before the Texas horizontal fin damage had run its course, resulting in a major problem being under-rated, its priority downgraded.  The first NACA Langley wind tunnel tests showed the fins’ heaviest pressure loads and structural strong points did not line up. Goodyear-Zeppelin proposed work-arounds, the most highly visible of which was to add a blimp fin-like reinforcing cable (see blueprint) at main ring 17.5. “Mr. Airship” CDR Garlon Fulton eventually vetoed the ugly cable, arguing it would interfere with the stern beam’s complex load-spreading bridle of cables used with the stern handling beam. The literature does not provide supporting  arguments in the form of cost analysis re: modifying the bridle, adequacy or inadequacy of internal-only reinforcements, or the like.  (If little more than a gut feeling based on long experience, or even just aesthetics, the fateful decision was still being emphatically defended decades later when author R.K. Smith interviewed Fulton.)

LZ 129 001f Bau (Arbeiten am Gerippe)Across the Atlantic another development had played out as the National Socialists continued to expand, taking over German industries judged useful to the 3rd Reich.  The propaganda ministry came to the conclusion Zeppelins would be a unique, visible and profitable asset to the Reich.  A memo from the propaganda minister for Hitler (later uncovered by Prof. Henry Meyer) urged the Zeppelin construction and operations be nationalized. The memo noted the German success, based on wide experience, while most all other countries had bungled rigid airship technology. The memo admitted the US Navy was still operating the ZRS-5, but the memo speculated the Americans would not have the Macon for much longer. Adolph Hitler okayed the plan, which would infuse cash to speed construction of the previously slow-moving LZ-129 project (above). The most immediately visible change was also concerned a tail127-op-l-tail – the LZ-127’s vertical fin port sides would become a huge National Socialist flags, to be flown about the world. The investment was seen as likely paying a tangible return – in gold-backed foreign currency.


Permanent reinforcement parts for Macon’s fins had been received from Goodyear-Zeppelin.  Between November 10, 1934 and February 10, 1935, a G-Z factory team and local sailors installed them, as time permitted, on the lower and horizontal fins. (Rigger William Clarke told the producer there was a great deal of wire tightening going on in the tail fins.) Surely these seemed like beefing up for the long term, down-the-road longevity. The overhaul period in March was also going to replaced much troublesome topside ramine cord netting, its broken strands having been patched constantly. One fix was completed and awaiting test: an improved 5-m radio installation in the cloud car.

Having executed the aforementioned fleet shadowing mission flawlessly 11-12 FEB 35, Macon was released about 1500 hours to return to base at Wiley’s discretion. Those last two planes were recovered at 1550 off Point Piedras Blancas, and Macon headed north for Point Sur, the gateway through the mountains to the Santa Clara Valley.  imag0151The weather and visibility deteriorated with foggy rain, and Wiley reduced altitude twice trying to duck under the fog. At the elevator wheel, AMM1 William Connover had just adjusted for a shallow dive and noted the ship entering a haze. As the Point Sur Light flashed into sight, Wiley ordered left rudder to check Macon’s nearing the rain-shrouded mountains. It was 1705. William Clarke held the rudder at about five degrees when the ship lurched to starboard and the rudder wheel spun out of Clarke’s hands. Two keepers in the lighthouse had put their glasses on her and were startled to see the Macon’s upper fin (seen here under construction) suddenly seem to disintegrate.

upper-keelCBM “Shaky” Davis, inspecting the stern as he’d been during during the Texas calamity, was in the upper keel (seen here in construction, less outer cover) at frame 23.75 when he heard a crashing sound. He started moving aft with crewman Joe Steele – the buddy system was in force whenever occupying the upper walkway, owing to the danger of helium anoxia. Unlike adding ordorant to hydrogen as a cheap leak detector, helium tended to take on less scent from its bags. Davis started noticing light-headedness and realized they were entering a free helium discharge so rich as to displace air in the lungs (and then the bloodstream, which is why it can cause death in as little as two deep breaths). Davis turned tail and, pushing Steele ahead, both men ran forward along the upper keel walkway. The stern was sinking, so it became an uphill climb with at least some free helium chasing them up the 4-inch wide walkway. Eventually reaching the telephone at frame 57, Davis attempted to report to the bridge, but found that line was busy. Still suffering from dizziness, they threaded forward until they reached main frame 170, where they descended into better air using the ladder therein.

Dr. R. K. Smith devotes four pages to the Macon’s last 90 minutes of confusion as remembered by participants. The established practice of stopping engines and performing a weigh-off seems not to have been considered. The ship would not respond to the bridge’s attempts to restore trim and control – but for reasons not directly related to the fin failure. Slip tanks were cut loose aft (their weight punching them through the fabric cover) and various attempts to valve helium forward failed to restore even trim. Off-duty crew and the airplane pilots were ordered forward, the climb performed in a fairly orderly fashion. (The centerline passageway is seen in this earlier photo. )

As recalled by photographer Carroll, one crewman grabbed chicken when passing the galley(!) Once huddled in the center passageway forward, he chowed down, explaining if he was going to meet his maker, he was going to do it on a full stomach. Leroy Simpler calmly finished a piece of apple pie he’d retrieved – he told the producer he and another pilot had been playing checkers in the Officer’s Ward Room when he felt the first lurch. Miller noted how cramped it was in the winch “room” (photo) and forward passageway. img605-copy-2

Though only whispered in airshipmen’s circles, it is known one officer panicked and ran the keels shouting for everything to be dumped overboard. Worse, this same officer opened each engine room door and shouted to the enginemen to ignore the telegraphs, and to keep the engines at full power.  The ship quickly passed through its pressure height of 2800 feet and continued to climb – even after losing the aft three cells and with automatic valves opening to dump helium. In the next fifteen minutes, the climb continued unchecked until the altimeter read 4,850 feet. Finally, with so much lift vented away, the ship started falling, its rate of decent reaching 750 feet per minute before engine thrust was turned upward to slow the fall. Remaining slip tanks forward were dropped to slow the final decent, since any hope of opening the hangar door and jettisoning the still wheel-less airplanes was thwarted by the hull’s steep angle.

Almost everyone had time to don a life jacket and the crew had the life rafts ready to launch when the lower vertical fin touched the water at 1739 hours.  Someone remembered to raid the metal locker in the navigator’s compartment for the flares and their pistols. Those carried in the airplanes could not be reached. Chief Radioman Daley had lost his glasses in the excitement, and abandoned ship from too great a height. Daley was likely knocked unconscious and drifted away even as the weather was calming down. Wiley had ordered an SOS sent first as a precaution, but the Fleet had reacted. Some of the crew, reluctant to jump in the cold water, sat top the giant bow still floating.  “Min” Miller remembered, “We shot off about twenty Very pistol shells from there. Then, blessed sight, we saw the beams of far-distant searchlights in answer to our radio for help…  For a moment I thought we were not going to get wet, but that proved to be an illusion. By this time we had only about fifteen feet of the hull left above water–just a bubble. I decided that I had enough and I wanted to make a boat before it was totally black. Besides, it was misting and getting more foggy. So, I threw away my shoes and started to slide down the cover. My foot slipped and the five ahead of me must have thought the ship was going down for they all leaped into the water like a bunch of wet rats. As it was the hull was breaking under our feet. Looking back I saw one lonely blue jacket remaining on the ship. I shouted for him to come on.”

Miller recalled that man jumped. However steward Florentino Equiba, afraid to enter the water because he could not swim, was last seen climbing on the structure. Miller continued, “When clear of the hull a fire started and at last the cover burned off as she went down.” If Equiba survived the covering fire retaining consciousness, he was possibly lost  in the sinking structure, if not simply drowning when it was gone.  Miller remembered the fabric’s fire in TIME magazine decades later, “The massive star insignia painted on the underside of the bow was reflected by the glare, even as it was consumed… the last skeletal remnant of what had been the world’s greatest airship slipped beneath the surface.” (Emphasis added.) CBM Davis was later commended for saving stragglers, keeping a cool head “…and remaining close to the hull even when fire broke out in the bow as it was sinking.”

While a hasty assessment could jump to the conclusion that, since the ZRS-4 & 5 design fin had been changed to anchor fin roots in the lightly reinforced intermediate frame 17.5, that the tails were destined to fall apart before 2000 hours of operation. Another author followed Rosendahl’s then-unpublished lead to suggest Akron’s tail had failed somewhat similar to Macon’s.  A case could be made that little-understood science of metal fatigue could not have predicted the weak fin roots would give up after such short service.  However, author Jeffrey Cook put all that to rest with his careful analysis, USS Akron  & USS Macon: An Engineering History Of Fin Design. Cook summarizes:

“From the facts and data examined in this thesis, the following conclusions can be made regarding the loss of the Macon:

(1) The use of incorrect fin pressure distribution assumptions reduced the actual strength of the Macon’s fins to the point where a sharp side gust of 31 ft/sec was sufficient to cause structural failure. Had the original fin design been used, this figure would have been essentially identical.  The incorrect pressure distribution assumptions constituted the critical factor leading to the loss of the USS Macon.

(2) The actual failure occurred in Frame 17.5; this frame is believed to have been weaker than expected due to the inadequacy of stress analysis techniques available at the time of design. The critical gust required to cause failure was therefore somewhat less than that predicted in (1), but how much less can not be determined.  It is likely that a similar deficiency would have affected Frame 35 had the original fin design been used.  The inadequate stress analysis techniques can be considered a secondary critical flaw, as it resulted in much more serious damage than would otherwise have been the case.

(3) All other proposed explanations for the Macon’s fin failure, including the redesign of the fins in July of 1931, are secondary to (1), and could not on their own have caused the failures which occurred.”

Jeff Cook’s research leaves no doubt as to the structural failure, possibly at a joint similar to this one further forward, photographed during construction.  

However, it must be said that even after the upper fin and its associated structure had caused the loss of two gas cells, as Rosendahl pointed out in his tell-all book SNAFU, “Zeppelins had been brought back with worse damage.”  As Dr. Richard K. Smith had stated, the panic reaction in the minutes following the casualty was the only true reason for the loss of the Macon.  The ship was still fully powered, controllable, and buoyant. In Smith’s correspondence and telephone discussion with the producer, he never wavered in the conviction the crew had erred. Likewise, the ironic German prediction of Macon’s loss months earlier was not based on any suspected structural defect. The Zeppelin men felt the US Navy’s path to advancement system based on fixed sea-duty-milestones was the problem. It guaranteed no one would gain enough experience in commanding rigids to become what they considered proficient.   With all due respect to the Captains and their senior officers, the US Navy’s system of jack-of-all-trades career paths played a major role in losing all three great rigids, from the first helium leakage to the final entry into the water.

The surviving Macon crewmen pose in front of the Admin building in this photo the morning after. Electrician Gilmore (4th from left, front row) had suffered burns to his hands sliding down a bow line, and is bandaged. (Crayon arrow points to Wilmer Connover, the Navy’ s last rigid’s elevator man.)

The Macon had made 54 flights, was aloft 1798.2 hours and traveled 90,546 nautical miles. The accident would not be seen in context of all air incidents, which continued unabated but were quickly lost to history. A few days after Macon sank, an airliner trying to establish a new air route between Germany and China crashed, fatally injuring the pilot and destroying the aircraft. The same year the world’s largest airplane, the Soviet ANT-20 ‘Maxim Gorky,’ crashed killing all forty-eight on board. Rosendahl would later observe, “Airplane crashes are statistics, airship crashes are disasters.”

The US Navy’s rigid airship program had from its first days consumed tens of millions of gold-backed dollars. The experienced gained also came at the cost of more than 100 lives. (Rigid’s development could be roughly compared to the toil and treasure expended to develop a practical submarine-boat, defined as one that would be more dangerous to the enemy than its own crews.)  However costly, the expenditure and airman’s sacrifice had perfected a flying aircraft carrier. These pioneers  had paved the way for the US Navy to continue development of a completely unique asset for its fleet. Near foolproof masting and advanced docking facilities had been built on both coasts. Expeditionary masts bases were placed in strategic locations around the American “empire,” with the Philippines the next logical step. A new more powerful Packard engine (to replace the imports that had powered ZR-3 through -5) was on the test stand (and would go on to power key players in the next war). A purpose-built hook-on airplane design was being developed.  An industry was in place to apply the lessons learned and build an even more capable, purpose-designed airborne carrier. Surely many believed that, like lessons learned and applied after the third submarine accident, or third airplane accident, a new generation of flying aircraft carrier would arise from Akron and Macon’s watery graves. Would it be ZRCV… or ZRN … or would the USN just hitch rides on Zeppelins?

Read on to Macon “Post-Mortem”


Read on to Tests of the “Years of Confusion”


Read on to Ground Handling Evolution

Purchase DVD The Flying Carriers

Purchase Akron & Macon: An Engineering History of Fin Design

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