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December 2001

An Integrated City University Responds to the WTC Crisis

Bold, High-Tech TV Magazine Invites "Study with the Best"
NYC Past in Full Array At Inaugural History Festival
CUNY Community Colleges: Vital to City Economy
Arthur Miller Drops Back In for Finley Award at CCNY Dinner
Archaeologists Research Vikings
Faculty Experts Join Collaboration on World Trade Center Future
New Research Foundation Head
Asthma Initiative at BCC Registers Major Success
Oysters Reintroduced to Bay
York Grad Makes Naval History
Managing the 9/11 Crisis at BMCC
Hunter Cartographers Prepare Vital Ground Zero Maps For Rescue
CCNY’s Rosenberg/Humphrey Interns Continue Public Service Tradition
City Tech Prof Sheds Light on Titanic
New Device for Medical Diagnonis
Mina Rees, Pioneering Military Scientist
Annual Perspectives Nears 25th Anniversary
University to HIV Children: “Toys (and Lots Else) Are Us”
 
 
City Tech Professor
Sheds New Light on Titanic


Like most of us, Dr. Richard Woytowich, associate professor of computer engineering technology at New York City Technical College, learned as a child of the tragic events of April 15, 1912, when the "unsinkable"RMS Titanic did just that on its maiden voyage, after striking an iceberg in the North Atlantic.

Professor Richard Woytowich with one example of robotic engineering, a field in which City Tech is extensively involved.
As a youngster, Woytowich had no reason to question the then commonly held—but now confirmed to be erroneous—notion that ice had sliced a long underwater gash, or series of gashes, in the Titanic's starboard hull, allowing the forward flooding that sealed the ship's fate.

Over the last three years, however, Woytowich has had a rare opportunity to become closely involved with the ongoing research into history's most famous maritime disaster. As a member of the Marine Forensics Panel sponsored by the Society of Naval Architects and Marine Engineers (SNAME) in co-operation with a number of other professional societies, his role in this research has been to investigate the design of the ship's riveted joints.

The panel had already determined, through metallurgical tests performed on samples recovered from the wreck in 1996 and 1998, that some of the ship's wrought-iron rivets were flawed. They contained an unusually high concentration of slag, a product of the smelting process, which made them brittle and prone to fracture. Woytowich, however, suspected that high slag content alone was not enough to explain what happened. He believed that the design of Titanic's joints might also have played a role in making the ship susceptible to collision damage.

His examination of late 19th- and early 20th-century technical literature indicated that ship designers of that era took a different approach to joint design. The practice today is to make the joints, insofar as possible, as strong as the plates they connect. Of course, riveted joints can never quite achieve this ideal, because the rivet holes themselves reduce plate strength.

In the first decade of the 20th century, designers used elaborate tables relating the number and spacing of rivets to the jointôs function and location within a ship. These tables appear to have been intended to match the strength of each joint to the forces it was expected to withstand in everyday service. Unfortunately for most of the 2,200 passengers and crew aboard the Titanic, the part of the hull which came into contact with the iceberg included some of the weakest joints to be found anywhere in the ship. In these areas, evidence indicates that the rivets failed from the force exerted by the iceberg.

A computer-generated image of the riveted plates compromised by the iceberg.
To better understand the behavior of these joints, Woytowich constructed a computer model, using a "finite element" program. (Such computer programs allow investigation of complex shapes by breaking them down into simple ones that can be solved mathematically.) He was able to reconstruct the joint failure, step by step. The final stage of the failure, in which enough rivets were overloaded to allow the hull plates to separate, is shown in the accompanying illustration.

Woytowichôs crucial finding was that plate separations occurred where only two rows of rivets, rather than three or more, were specified to join the plates. These separations created a breach in the ship's hull totaling approximately 12 square feet—about the surface area of a human being of average size and enough to allow more than 25,000 tons of water to flood the bow of the 46,000-ton ship. The added weight was more than the Titanic could withstand and stay afloat. Where three or more rows of rivets were used, and where the rivets were made of steel rather than wrought iron, the plates remained joined.

Woytowich completed his research too late for it to be included in a paper presented by the Marine Forensics Panel at SNAME's Annual Meeting in October of this year. However, with the cooperation of the panel's chairman, William Garzke of the naval architecture firm of Gibbs and Cox in Virginia, he was able to present his findings as a discussion. Consequently, his results will be published along with the rest of the Panel's findings in the Society's Transactions for 2001.

When asked what lesson today's ship designers could learn from these investigations, Woytowich responds that they need to think very carefully when deciding what conditions to design for. He noted that the sea is still a challenging environment, in spite of all our technological sophistication, and has a way of revealing, sometimes at terrible cost, the weaknesses in any vessel's design and construction.