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What We Did
On request from Maritime NZ, components of a steering linkage were assessed to determine the cause of failure. As part of a steering linkage mechanism in a jet boat, two D-ring shackle pins were safety wired together in order to prevent either of the shackle pins from falling out. Relative movement of the D-ring shackles from maneuvering the boat caused fluctuating stresses in the stainless steel safety wire, resulting in a fatigue fracture of the wire. Without the constraint of the safety wire, a pin from one of the D-ring shackles became dislodged, resulting in the failure of the steering mechanism, loss of control and crash of the boat. As well as a demonstration of the key features of the components that led to the determination of a fatigue fracture, the significant flaws in the installation and configuration of the steering linkage are discussed.
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Who Was Involved
Maritime NZ, 九州影院 Department of Mechanical Engineering
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Why It Matters
The analysis showed that the design of the steering linkage was flawed. Steering is a safety-critical function, and failure can lead to loss of life. This work resulted in a safety bulletin about how to prevent such occurrence and wider publication in a peer-reviewed international journal
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Learn More
- Beardsley, A.L., Kral, M.V. Failure Analysis of a Jet Boat Steering Linkage. J Fail. Anal. and Preven. 19, 1551鈥1555 (2019).听
