The Novel Design Failure from Liberty Ships to Ocean Gate Titan

The unfortunate incident of the lost submarine “Ocean Gate” brings to the memory the historical incidents of the liberty ships during World War-II as both are failures of innovative novel designs considered as first in class successful designs by their innovative developers.

Ocean gate titan which lost while was on a tour of the Titanic wreckage off the coast of Newfoundland, Canada carrying five passengers. A U.S. Navy official said the Navy detected "an acoustic anomaly consistent with an implosion" shortly after the sub, named Titan, lost contact with the surface. [2]

The lost sub was fabricated from carbon fiber cylinder and titanium heads and considered as a first-of-a-kind carbon fiber hull[1].

The trending use of carbon fiber material in airspace is known due to its high strength and light weight. And titanium is of Competitive properties as well. Carbon fiber composites can be stronger and lighter than steel, making a submersible naturally buoyant. But they can also be prone to sudden failure under stress.

The lost sub was designed by experienced innovative professional engineer and reviewed by NASA (as claimed).

The Report prepared by ex-director of marine operations at Ocean Gate, in 2018 recommended that non-destructive testing of the Titan’s hull was necessary to ensure a “solid and safe product.” while such testing was impossible, and that Ocean Gate would instead rely on its much touted acoustic monitoring system[1].

The company claims this technology, developed in-house, uses acoustic sensors to listen for the tell-tale sounds of carbon fibers in the hull deteriorating to provide “early warning detection for the pilot with enough time to arrest the descent and safely return to surface.” However, that the system would not reveal flaws until the vessel was descending, and then might only provide “milliseconds” of warning before a catastrophic implosion.

On other hand the sub was provided by a joystick Bluetooth game controller which points fancy design control for critical application. 

Liberty Ships

In world war-II revolutionary design for ship fabrication was developed by Henry Kaiser a famous US construction engineer by using fully welded design instead of riveted construction. The innovative welded hulls allows for fast fabrication of large size vessel to meet the high demand for the war to carry the supplies.

Around 2700 Liberty ships built during world war II, approximately 400 fractured including 20 ships broken completely in two. [2]

Most of the fractures, initiated on the deck at square hatch corners at local stress concentration area.

The steel used was of poor toughness but successfully used for riveted applications in earlier design as cracks could not propagate across riveted panels. On other side for welded joints, the joint is basically became as a single piece allowing for crack to propagate till failure. 

Once the causes of failure were identified, the remaining Liberty ships were retrofitted with rounded reinforcements at the hatch corners. In addition, high toughness steel crack-arrester plates were riveted to the deck at strategic locations. These corrections prevented further serious fractures.

In the longer term, structural steels were developed with vastly improved toughness, and weld quality control standards were developed. [4]

Common Themes in Design Failures

1. Rapid Prototyping and Testing:

• Both the Liberty Ships and the Ocean Gate Titan highlight the risks associated with accelerated development without comprehensive testing.

• The need for thorough prototyping and testing to identify and address potential design flaws.

2. Materials and Manufacturing:

• The Liberty Ships' welding issues draw attention to the critical role of materials and manufacturing processes in maritime design.

• Ensuring the use of suitable materials and employing robust manufacturing practices remains paramount in modern maritime innovation.

3. Integration of Technology:

• The Ocean Gate Titan's challenges underscore the complexity of integrating cutting-edge technology into maritime systems.

• The importance of a systematic approach to technology integration, considering the unique challenges posed by the maritime environment.

Captured Lessons

• Being well designed following available developed rules, does not proof the adequacy of the design. Simulated life testing, non-destructive testing and/or application in identical conditions is necessary.

• "When an ‘‘improved” design is introduced, invariably, there are factors that the designer does not anticipate. New materials can offer tremendous advantages, but also potential problems. Consequently, a new design or material should be placed into service only after extensive testing and analysis." said by Dr. T.L. Anderson

• Although, it looks to be against innovative thinking and development of new technologies, I am a fan of “DO NOT USE UNPROVEN DESIGN IN REAL HAZARDOUS APPLICATIONS".

Many other lessons learned can be captured, but I tried to make the article short, references are added below for more details,

At the end, this article is to share my thoughts as in industry we are facing frequent cases where novel and innovative designs are offered with highlighted benefits either in cost or production increase while relying in theoretical research and advanced simulation software. One should be careful in adopting such designs especially in hazardous and critical applications.

Bibliography

[1] https://www.cbsnews.com/news/missing-submarine-titanic-debris-field-oceangate-us-coast-guard

[2] Williams, M.L. and Ellinger, G.A., ‘‘Investigation of Structural Failures of Welded Ships.” Welding Journal, Vol. 32.

[3] Fracture Mechanics Fundamentals and applications, T.L. Anderson

[4] Van Duyne, S. Liberty ship breakups. In When Technology Fails—Significant Technological Disasters, Accidents and Failures of the Twentieth Century; Schlager, N., Ed.; Gale Research Inc.: Detroit, MI, USA, 1994. [Google Scholar]

[5] Technical Problem Identification for the Failures of the Liberty Ships, Wei Zhang.

[6] https://www.sciencedirect.com/topics/engineering/liberty-ship