Crew of British research vessel gathers extraordinary and dangerous data on waves

The crew and scientists aboard the British ship RRS Discovery expected a routine scientific voyage to study global warming in the North Atlantic, perhaps with some rough seas. What they got instead was a terrifying ordeal and a fight for survival atop the largest waves ever measured on a ship.

They won’t ever forget the chaotic conditions they endured off the Scottish mainland during the overnight of Feb. 8-9, 2000.
For several hours, waves as high as 60 to 95 feet battered their 295-foot research vessel. Scientists were thrown from their bunks. Windows broke. The ship almost collided with a trawler. A lifeboat came loose and was banging against the starboard side. People suffered bruises and broken ribs.

Navigating the monster waves near the island of Rockall, about 175 miles off the west coast, was a crew led by Capt. Keith Avery. He said some of the ship’s occupants begged him to run to a sheltered position along the mainland. Instead, Avery calculated that it was safer to face the bow into the oncoming waves and ride out the storm with engines at half speed. The perilous rollercoaster ride lasted all night.
“I think a lot of people were scared,” Avery said. “There was violent movement on the bridge. The engineers were suggesting, so to speak, that we would be better off if we turned ’round and ran. But the only thing to do was to heave to and ride it through.”

The “hove to” position paid off for the crew of 22 plus 25 researchers. Not only did everyone survive, but they also were able to report on the largest waves ever measured by scientific instrumentation on a ship.
Discovery’s wave recorder measured one wave at 95.5 feet from crest to trough. The so-called “significant wave height,” which averages a series of high waves in a single storm, was 60.7 feet — also a world record.

The lead scientist on Discovery was Naomi Holliday, senior oceanographer at the National Oceanography Centre at Southampton, England. The report was published this year in the journal Geophysical Research Letters.

For at least five days, no scientific work was possible on Discovery because of the awful weather, which was caused by a low-pressure system and constant westerly winds, Holliday said.
“It was quite frightening,” she said. “Everyone’s cabins were turned upside down. Everything that wasn’t nailed down was flying around. Chairs flew into bunks while people were trying to sleep, and we had some people who ended up with broken ribs when they were tossed around.”
Avery, a mariner with three decades of experience on research ships, said it was somewhat difficult to maintain the “hove-to” position. The waves didn’t always strike from the same direction, and it was too dark to see them coming. Winds gusted as high as 78 knots.
Large cracks developed in a 6-foot-wide window in the computer room amidships. This suggests that the ship twisted, Avery said.

Avery, now 63 and retired, said his most enduring image of the struggle is of the starboard lifeboat when it was knocked free from a clamp. Several crewmen worked together to secure it.

“The ship rolled maybe 28° to port and then she rolled 30° to starboard, and we heard this sort of a ‘twang.’ It was dark on the foredeck, but we could see that the lifeboat came adrift,” he said. “That’s the thing I’ll remember.”

The catering manager was injured when he lost his balance while brushing his teeth. The chef was hurt when a door struck him.

A steep roll emptied the contents of a refrigerator, transforming the non-slip deck into a treacherous slop of “tea, milk, biscuits and broken crockery,” Avery said. “The only way to remain upright was to walk barefooted until it was possible to clean the mess.”

While the waves were the highest ever recorded in an official ship-borne measurement, they are not necessarily the largest ever observed. Stephan Grilli, a professor of ocean engineering at the University of Rhode Island, said anecdotal reports from aircraft carriers and oil platforms mention waves around 100 feet. A Canadian buoy estimated a 98-foot wave in the western North Atlantic during the October 1991 “Perfect Storm.”

Holliday said the swells off Rockall in 2000 were caused by a “resonance effect” — waves and wind moving across the ocean at the same speed. The waves get larger by constantly feeding off energy from the wind.

“The wind pressure creates the resonance effect, sort of like pumping your legs on a swing,” said Grilli. “I know of another case off Virginia Beach where there was a squall moving very fast, and a wave struck the beach and went over the sea wall and washed some cars away.”
What is notable for the UK researchers is that the existing scientific models, when the weather data were entered later, underestimated the size of the waves that actually resulted, Holliday said. The modeling suggested a significant wave height of only 47.6 feet — 13 feet fewer than what actually occurred. Because the simulators may be adjusted, the researchers expect the findings to impact the engineering of ships, oilrigs and marine windmills.

Avery can vouch for a bit of shipbuilding work that was already done. In 1992, he observed his circa-1960s Discovery being retrofitted at dry dock in Viana do Castello, Portugal. The shipyard literally split the hull and lengthened it by almost 33 feet. Eight years later off Rockall, Avery realized that the storm, which was twisting his vessel, was the ultimate challenge for the 1992 welds.

“I thought, ‘You won’t get a better test than that,'” he said. “This case proves the Portuguese work was quite good.”

The scientists also appreciate the job done at the Portugal shipyard and Avery’s sound judgment during their time of peril. “We are eternally grateful to him and his crew for managing to get us home,” Holliday said.

By Professional Mariner Staff