Stability questions in tour boat capsize

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Some experts speculate that the Ethan Allen’s deck had been raised, changing its center of gravity

Some experts speculate that the Ethan Allen’s deck had been raised, changing its center of gravity

Several naval architects and marine engineers point to possible modifications in the deck height of the tour boat Ethan Allen as the reason it capsized Oct. 2 on Lake George in New York, killing 20 mostly elderly tourists.

But the company that owns the boat says it never changed the deck height.

The experts who are speaking out caution that they have had only photographs on which to base their conclusions. In those photographs, the deck appears to be at the same level as the boat’s gunwale, and experts say that means the boat would become increasingly top-heavy every time another passenger boarded.

The National Transportation Safety Board was unwilling to provide details of the boat’s construction or modifications, which would confirm the deck level, until its investigation is completed. That could take up to two years, according to the NTSB. New York State regulators had no information on the deck level, and the boat’s owner, Shoreline Cruises, would say only that it hadn’t modified the deck.

But while state officials focused on the number and weight of passengers, and the availability and on-board explanation of life jackets, naval architects and marine engineers were cramming onto Internet forums to point to the deck as the cause.

“I was shocked to see the pictures of the boat with the deck so high, and that this boat was licensed by the state of New York,” says powerboat guru Eric Sorensen, who says he is familiar with the Ethan Allen’s Dyer 40 hull. “The cockpit deck is 6 to 8 inches above the waterline” in a typical Dyer 40, says the author of “Sorensen’s Guide to Powerboats: How to Evaluate Design, Construction, and Performance.” “In this boat, from the photos I’ve seen of it, the Ethan Allen’s deck was level with the gunwale. That’s probably 2 feet higher than the deck is ordinarily. You could get away with that if you had a few people. But when you put 50 people on it — let’s say they weighed 180 pounds each — that’s 9,000 pounds of weight that’s 2 feet higher than it should be. It shows an astounding lack of understanding of stability and the elements of seaworthiness.”

Bruce Johnson, a retired professor of naval architecture at the United States Naval Academy in Annapolis, Md., and author of a text on the subject, agrees with Sorensen’s judgment. He says the Dyer 40 was built with a “well deck” below the gunwale for a purpose. “There’s a reason you climb down [into a boat],” Johnson says. “It’s to lower the center of gravity. Weight high is just no good.”

Shoreline Cruises, operator of the Ethan Allen, referred questions to a public relations firm. Spokesperson Drew Ferguson says Shoreline made two modifications to the Ethan Allen: It repowered with a more powerful engine, and replaced the steel and canvas canopy with one made of wood. He says Shoreline didn’t modify the deck.

Wendy Gibson, a spokesperson for the New York State Office of Parks, Recreation and Historic Preservation, which regulates tour boats in waters under the state’s supervision, confirms the canopy and engine modifications made by Shoreline. She says state inspectors decided at the time that new stability tests of the Ethan Allen weren’t needed. Gibson says the state has no record of a modification to the deck.

State inspectors are “all graduates of maritime academies with degrees in marine transportation, nautical engineering. They are proficient in the rules of the road, naval architecture, things like that,” Gibson says.

Built in 1966 the Ethan Allen was rated for 50 passengers when it came into New York waters from Connecticut 20 years ago, Gibson says. The boat had undergone annual inspections in New York, during which inspectors looked at the safety equipment, propulsion systems and “an overview of the seaworthiness,” Gibson says. In all those inspections, there apparently were no concerns raised about stability.

“Anybody that has any familiarity with that type of boat would be taken aback by the height of the deck coupled with the fact that the boat was licensed to carry 50 people,” Sorensen says. “I was just blown over.”

Sorensen explains that the Dyer 40 is a round bilge boat, meaning the hull rounds from the sides to the bottom, rather than coming to a ridge as in a hard chine boat. A round bilge boat has lower initial stability than a hard chine, he says, but the design makes for a more comfortable boat in rougher water.

“The Dyer 40 has a wonderful motion, very comfortable,” says Sorensen. “If the weight distribution is low … then they are very seaworthy boats, more comfortable than most hard chine boats. But when they put that deck up so high and put 50 people on it, you lose stability.”

Johnson, the retired professor of naval architecture, speculates that at some point someone decided to make the Ethan Allen accessible to handicapped passengers. Raising the deck means that passengers could simply step — or wheel — from the dock onto the boat without having to step down, he says. “It’s possible that the Americans With Disabilities Act had an impact,” he says.

While Sorensen doesn’t discount the impact that changing the boat’s canopy or engine might have had on stability, he says, “The egregious part of this whole formula is that they put that deck up so high and had 50 people on it.”