ARTICLE

August 2004

Navy Searches for Ways To Lower Injuries Aboard Special Ops Boats

by Sandra I. Erwin

In an effort to reduce serious injuries, the U.S. Navy is retrofitting its special warfare high-speed boats with new shock-absorbing seats.

The high-speed crafts, called Mark Vs, have been in operation since the mid-1990s, but it took several years for the U.S. Special Operations Command to determine, through medical surveys, that the crews were suffering an unusual high rate of injuries, ranging from sprained ankles to broken backs and whiplash.

“When guys ride these boats at 45-50 knots, in significant sea states, they were getting injured,” said Cmdr. Robert Womer, former chief of maritime programs at the Naval Special Warfare Command.

The 57-ton Mark V typically carries special operations forces, primarily SEAL combat swimmers. Both the craft operators and passengers get hurt during rides, but the crews experience a higher level of injury because they spend more time on the boat.

In response to unofficial injury reports, the NSWC in 1998 kicked off a number of studies to try to pinpoint the cause of the injuries, which many already suspected resulted from the intense pounding that craft operators were taking during high-speed rides.

“They found the dynamic forces they were experiencing when riding the craft were sufficient to cause significant injuries,” Womer told National Defense. Gravity forces at 45-50 knots, and the momentum created with rapid accelerations and decelerations, can put tremendous stress on the human body, no matter how physically fit, he noted. “If the seas are calm, we would not experience many injuries. Turbulent seas are a major factor.”

After completing several shock-mitigation studies, the Naval Special Warfare Command concluded that the Mark V seats needed to be replaced. Two civilian government employees came up with a novel concept for a shock-absorbing seat, Womer explained. To make the new seats, the original seat manufacturer, a company called Stidd Systems Inc., of Greenport, N.Y., partnered with Taylor Devices Inc., of North Tonawanda, N.Y., which produces shock absorbers like those used in cars.

The companies created a shock-absorbing seat that looks like the original, but is mounted into a rigid frame, so it allows about seven inches of vertical movement, up and down.

The Navy purchased 400 seats, enough to equip all 20 Mark V boats now in operation. Each boat has 21 seats, but only 20 will be swapped. All 400 will be installed by the end of the year, said Womer.

“It takes a long time to produce 400 seats,” he said. “We are replacing the front couple of rows first, because that is where the crewmen sit. Back rows are for passengers, and they are not exposed to the same degree of dynamic force as the crewmen.”

But even after the new seats are in place, the injury problem may not go away, Womer added. “We are not certain that all these injuries are from boat rides. We think we know, but did not institute a really robust medical surveillance program until fairly recently. ... We don’t have any really good figures on the true injury rates.”

Also complicating attempts to study injury patterns is the lifestyle of special operators, noted naval special warfare spokesperson Patricia O’Connor. “These are hard-charging warriors,” she said. “They don’t want to complain that they have a sore back. If they do, inevitably they may be asked by their boss to sit out a mission.” They also tend to practice strenuous sports, she added. “On their off hours, they are mountain biking, skiing, doing all kinds of activities that could possibly impact their body. We need to try to capture that data as well, and get a better picture of what these guys are doing.”

Another ergonomic upgrade planned for the Mark V is to move the throttle control from the engineering panel—which is located 3.5 feet away from the driver—to the armrest mount. The driver has to lean over frequently, or even get out of his seat, to slow the boat down or speed up. Moving the throttle position from the engineering panel up to the armrest allows the operator to control from his seat both the speed and the direction of the boat.

The U.S. Special Operations Command recently approved funding for the throttle-control modifications.

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