REF NO.: 219
|SUBJECT:||Engineer believes the danger of icebergs is underestimated; Titanic’s lesson being forgotten|
|DATE:||April 13, 2004|
According to Dr. Claude Daley, professor and chair of Ocean and Naval Architectural Engineering at Memorial University, the Titanic disaster is far enough in the past that people are forgetting the lessons of that tragedy. He says the risk of a ship being destroyed by an iceberg hasn't gone away since the Titanic disaster.
Dr. Daley, who is also the director of the Ocean Engineering Research Centre at Memorial, recently finished a report titled A Study of the Process-Spatial Link in Ice Pressure-Area Relationships for the Program on Energy Research and Development (managed by the National Research Council of Canada). In it he talks about ice pressures in collisions and concludes that in large scale collisions the ice forces – the amount of pressure exerted by the ice on the hull of a ship, for example – are likely being significantly underestimated.
Dr. Daley says ships today are better built than they used to be, but are still not strong enough to withstand a collision with a large iceberg. "People believe shipbuilding has evolved to the point where it can't happen again," he said. "Studies have suggested that Titanic's steel was much weaker and more brittle than modern steel. But, of course, nobody measured the ice loads on the Titanic. We don't really know how strong the Titanic should have been to survive that iceberg collision. I doubt if any ship afloat today, even one the size of Titanic, would survive such a collision without major flooding."
The increased risk, Dr. Daley noted, comes from an apparent trend that can be seen in all plots of ice load data. He says the trend has been normally interpreted to mean that the ice gets softer as a collision progresses. "We ice specialists have talked ourselves into the concept of ‘softening ice’ and I'm beginning to think we've made a gross error," he explained. "Researchers have been looking at the obvious overall pattern in the data, but unfortunately this may have all the meaning of patterns of stars in the sky, which is none. When I examined the data more closely, looking at the internal trends in the data, a very different result emerged. The ice appears to behave very differently than the way suggested by the ‘softening ice’ theory. In fact the ice seems to get stronger as the collision progresses. This would result in much higher force predictions for large collisions."
Dr. Daley says the belief that ice softens, coupled with somewhat stronger ships, means that some ship owners and regulators believe that things are quite safe. "When people think they're safe, they tend to act in ways that lowers safety," he said. "For example; most ice-strengthened vessels are only designed to hit thin ice without damage. Thicker ice is just as dangerous to these vessels as it is to vessels not designed for ice. Yet, sometimes inexperienced operators, told they have an ice-worthy vessel, tend to think their ship is safe for any ice. Even experienced operators can be prone to pushing operational limits until their ship gets damaged. Education, training and experience continue to be the keys to preventing future disasters."
Dr. Daley says platforms such as Hibernia and the floating production, storage offshore (FPSO) vessels add a whole new element to ice risks. "Most ice-going vessels are relatively small, and transit through relatively thin ice. The forces are limited by ship size and ice thickness. Furthermore, most ice-strengthened ships are built similar to previously successful ice-going ships. In such cases we don’t rely only on our models and theories of ice forces," Dr. Daley notes. "However, the ice forces on large platforms like Hibernia and the FPSOs are very large. We've never had a chance to properly measure such large forces in a similar situation. We're extrapolating far beyond the level where we have data. We are relying on theories, theories that might be wrong. We certainly need to continue to study the nature of ice forces, and the risks posed by ice."
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Biography - Dr. Claude Daley
Dr. Daley graduated from the University of Western Ontario in 1977 (civil engineering), and went on to Princeton University to complete a master's degree in structures and mechanics. In 1979, he joined Arctec Canada Limited (now BMT Fleet Technology) in Ottawa. In 1989, he was posted to Helsinki in a collaborative research project between Canada and Finland. During three years in Helsinki, he obtained a doctorate of technology in the area of ice mechanics and arctic naval architecture. Dr. Daley joined Memorial University in 1995. During the 1990s until now he has worked on the new international unified requirements for polar ship construction, being developed by the International Association of Classification Societies in conjunction with many national governments (including Canada). That work has guided and informed most of his research activities. His current research focuses on ice mechanics and ice loads on ships; plastic strength and design of ship structures; concepts for rational ship structural design regulations; structural risk and related matters. Dr. Daley is also a member of the International Ship Structures Committee and a member of the committee on Condition Assessment of Aged Ships.