As Knott’s Moves to Improve Safety, Another Mishap

As Knott’s Berry Farm prepared to reinforce its wooden GhostRider roller coaster, the spate of amusement park accidents continued Wednesday when a corkscrew roller coaster at a Vallejo park stopped suddenly, stranding 28 passengers high in the air in 100-degree heat.

No one was injured when the Boomerang ride at Six Flags Marine World broke down, but two women were treated for heat exhaustion.

The mishap follows Monday’s accident that injured five riders on GhostRider and two fatalities at Paramount-owned parks, one Sunday on a free-fall ride in Santa Clara and the other Monday night on a stand-up roller coaster outside Richmond, Va.

The Boomerang, which carries riders through two corkscrews and a vertical loop, got stuck after the mechanism that lifts the cars at the beginning of the ride failed to detach itself, park spokesman Jeff Jouett said. Three hours after the mishap, four riders were still stuck 70 feet above the ground.

Knott’s will begin installing metal safety devices today on GhostRider, but industry experts remain perplexed over the accident on what is billed as the longest wooden roller coaster in the West.

Wooden roller coasters have proven designs with tremendous safety records over decades of use, said Michael M. Black, chief executive of Roller Coaster Corp. of America in Atlanta, a leading manufacturer of wooden coasters.

“They just very seldom have problems,” Black said. “I’ve heard of people running trains together and things like that, but they just don’t come apart.”

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That’s what makes the Knott’s accident, in which a three-foot shard of wood broke loose beneath GhostRider’s cars and struck five riders, so confounding to the experts, he said.

Wooden roller coasters are held together with a large number of 5/8-inch and 3/8-inch bolts, typically used every three feet.

“For a board to just come off, I don’t understand it,” Black said. “I can’t imagine a piece of wood coming off a laminated track. . . . It doesn’t make sense.”

GhostRider’s designer, Denise Dinn-Larrick of Custom Coasters Inc., was not available for comment Wednesday. After examining the Knott’s ride Tuesday, Dinn-Larrick returned to her company near Cincinnati, where she approved plans by Knott’s to install metal bracing straps and ribbed nails in the stacks of wood beneath the coaster.

Black said his company, a Custom Coasters competitor, has no plans to make safety modifications on the wooden coasters it has built because it believes the accident at Knott’s was a freak event.

But, unknown to passengers, bolts on wooden roller coasters often break because the wood has built-in flexibility to handle the trains’ weight and the bolts do not, said Ray Rieger, a spokesman for the Assn. of Amusement Ride Safety Officials.

He supports pending legislation in California that would regulate the industry and require inspections and reporting of accidents.

“Wooden roller coasters are built to sway and move. Things can easily come apart,” said Rieger, whose group sets design standards for theme park rides.

However, the pieces of wood held together by the bolts usually don’t fly off, Rieger said.

“There are so many redundant bolts and fasteners in a wooden piece. They are designed so that they will not fall off and strike someone,” he said. “I’m really surprised that something like this would happen. It’s kind of baffling.”

Like all wooden coasters, GhostRider travels over a stack of lumber that acts as a shock absorber and provides strength. The 2-inch-thick boards are mainly eight or 10 inches wide, but pieces with smaller widths are also used on curved sections.

It was one of those small pieces--a 2-inch-wide, non-weight-bearing board--that broke loose Monday. The most seriously injured rider, a 58-year-old Japanese tourist, required six stitches to close a gash on his head and was hospitalized overnight for observation.

The general manager at Knott’s, Jack Falfas, said the type of construction used on GhostRider has long been the standard, adding that it was unheard-of before this week’s accident for a wooden trim piece simply to snap loose.

“This design--what they did with the board--goes back to Denise’s father and the original designs when they put curves in coasters,” Falfas said. “Sometimes when something works for so many years no one ever questioned it.”

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Nevertheless, Falfas said, Knott’s will use metal straps to bind the stacks of wood over which GhostRider travels, as well as nails driven into the support boards for extra strength.

About 60% of GhostRider’s 4,533-foot length is curved and has the trim pieces, Falfas said. On all those curves, Knott’s will drive home the extra nails and wrap three metal straps around every eight-foot section of the wood.

Falfas declined to predict when the ride would reopen. It first opened in December as the most heavily promoted attraction at the Buena Park amusement park. He said the safety work will begin today and probably will continue “for three or four days.”

Following the accidents this week, park operators across the country are reviewing safety procedures, said Paul Ruben, North American editor for Park World, a British magazine covering the industry.

Paramount, a subsidiary of Viacom Inc. in New York, has closed seven roller coasters and free-fall rides at its five parks in the United States and Canada.

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The Associated Press contributed to this story.