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[Editor's Note: this piece is to be presented as part of the Eco Roundtable.
WHEN: Tuesday, May 20th, 6:00-8:30pm
WHERE: The Peace & Freedom Convention Hall on Hardy Street, Lihu’e
Come and participate.]
by Juan Wilson on 20 May 2008
Humpty Dumpty sat on a wall.
Humpty Dumpty had a great fall.
All the king's horses and all the king's men
Couldn't put Humpty together again.
Bad things happen
Here are two examples of Humpty Dumpty structures:
1) The Hyatt Atrium: In 1981, there were 2000 people on the balconies of the Kansas City Regency Hyatt atrium dancing to a musical live performance when the structures suddenly collapsed.
The structural postmortem of the disaster discovered another example of how a small detail can screw things up. The three tier balconies were hung on steel cables. The load of the balconies were transferred to the cable by a washer and nut system.
The structural design and the components were all adequate. It was the in the erection of the balconies where things went wrong. In the concealed detailing, the contractor wanted to hang each balcony of the one above it, not directly to the cable. This meant that the washers on the top balcony actually received three times the expected design load. That was close to the fully loaded safety factor built into the performance of the washers. The balconies went up with
no problem observed, until a full and moving load was applied to the structure.
2) HMS Titanic: A recent review of the circumstances surrounding the sinking of the Titanic has produced a new theory of that tragedy. The Titanic as designed as an unsinkable ship. It was well engineered. The new theory posits that the ship would not have sunk if it had been built as designed and specified. The problem was the rivets. At the time the Titanic was under construction there was lots of ship building in England. So much so that there was a shortage of
rivets of the specified structure quality. The design and material of the hull was sufficient to withstand the collision with an iceberg. The brittle crumbly rivets were not.
A similar problem has come to the public's awareness regarding the Superferry Alakai. Reports from employees of Austal indicate that the butt welds on aluminum plates were compromised by non-union uncertified welders on the line and poor quality control.
HSF: No proof of concept
It now appears that the Superferry vessel Alakai was built as badly as it was sold to us. Most of us are familiar with that process. The HSF Corporation, the Governor and State DOT had to take shortcuts. They had to hide things. They had to bully people.
They avoided the required EIS by trickery. They foisted $40 million dollars of harbor improvements on the taxpayers of Hawaii. They had to make deals with the military that they tried to obscure yo obtain the federal loan guarantees they needed.
This building program of gigantic catamaran vessels for the Superferry followed the "successful experiment" with the WestPac Express ferries built for the U.S. Marine 3rd Expeditionary Force stationed Okinawa Japan.
The Hawaii program would supply vessels for strategic use by the Army's Stryker Brigade that was to be based in Hawaii. The program would also be a prototype for the Joint Venture High Speed (JVHS) vessel program.
This meant the vessels did not have to be practical for civilian ferry use, but for practical military use. Bigger and faster, rather than smaller and more economic.
Austal, had to get set up on the mainland U.S. to meet contract requirements. Austal is expert in building large high speed aluminum multi-hulled vessels. They knew that pleasing the U.S. military with the "civilian" Superferry could lead to much more work.
The JVHS prototypes would demonstrate their utility and lead to multi-billion dollar programs for that class of warship. However, the JVHS vessel was just one the new types of ships planned by the U.S. military. An even more ambitious program was the Littoral Combat Ship (LCS) program designed on a trimaran hull.
Together these programs would transform the Navy, our strategic capabilities in the Pacific and around the world and make J F Lehman Inc. a very rich investment firm.
Austal wanted both the JVHS and LCS contracts. The Superferry would be the progenitor for the JVHS, but they needed to rush through the construction of the Alakai to be able to have a go at the winning LCS prototype contest.
Some bad things happened on the way to the bank. In rushing the process. they over engineered the Superferry design solution and did an shoddy job putting it all together. The size of the Superferry and the performance requirements forced an overcomplicated arrangement for steering and keeping the ship stable.
Lots of delicate computer aided control of too many moving parts were required for trying to provide a comfortable ride. These moving parts all had to penetrate the aluminum hull near the transom. This is where the forces of stabilizing and steering the HSF leviathan through the heavy seas would all come together.
The original plan was to do the low speed steering by adjusting the power and orientation on the four 10,000 horsepower swivel thrusters. High speed steering would be accomplished through hydraulically controlled drag plates. All this was not enough however. Late in the game Austal had to introduce rudders to aide in the task. All together this was a lot of action and penetration to the aluminum hull in tight quarters.
This turned out to be impossible in high winter swells between Oahu and Maui.The Superferry was quickly nicknamed the Vomit Comet and soon ocean water was detected entering the hull.
HSF: A falling apart
It was at the rudders posts sleeves entering the two catamaran hulls that the first leaks and cracks were detected.
• At one time in the history of engineering, a successful new design would be achieved through calculations combined with physical models and prototypes. Today just about all structural design is done with computer calculations and simulations. It is not until the project is built that public discovers that they are the guinea pigs riding a prototype. Problems occur where many engineering disciplines come together and underlap in considering all aspects of a
complex situation. The Superferry was engineered with approximately twenty major software packages. In many cases software aplications underlap ory overlap functions. The design that emmerges is like the picture on an elephent that emmerges from the examination its separate parts by blind men.
• The hull's structural engineering was "minimized" using finite element analysis to make the system strong yet light. Kind of like an eggshell. The success of this kind of design is based on obtaining predictable quality in the form-factor and material performance. Like an eggshell, any imperfection or weakness can translate into catastrophic failure. Finite element analysis is most reliable when there are smooth continuous surfaces and edges.
Discontinuities, punctures and irregularities makes for unpredictable results when dynamic loads are applied to the structure.
• The desired performance of the hull could only be realized if the construction techniques resulted in conformance with the computer prototype. This could only happen with meticulous supervision of qualified workers with fail-safe quality control. This was not the case in building the Alakai. In the rush to finish the hull on time quality control suffered and unqualified workers were put to use. Butt welds were not done with uniform excellence. Mistakes were
covered over. Like the Titanic, failure to meet uniform quality of the joining of structural elements could be disastrous.
Once the rudder post sleeve connections cracked the Alakai had to go to dry dock. It ran aground on the way there. A tug pushing it of the reef caved in the side of the hull. Once in the submerged drydock some of the block put in place to support the keel were misplaced. When the drydock raised the hull some block missed the structural ribs of the HSF and the hull failed at those points.
It's all been patched up. All the bondo and duct-tape has been painted over, and Humpty Dumpty is sailing again... but the this eggshell is still a bad yoke.
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