July 22, 2004
Monster Waves Major Cause Of Large Ship Sinkings1
Susanne Lehner, Associate Professor in the Division of Applied Marine Physics at the University of Miami and Wolfgang Rosenthal of the GKSS Forschungszentrum GmbH research centre, in Geesthacht Germany used synthetic aperture radar data of the oceans collected by two European Space Agency satellites to find that huge 25+ meter high waves are far more common than previously thought.
Once dismissed as a nautical myth, freakish ocean waves that rise as tall as ten-storey apartment blocks have been accepted as a leading cause of large ship sinkings. Results from ESA's ERS satellites helped establish the widespread existence of these 'rogue' waves and are now being used to study their origins.
Severe weather has sunk more than 200 supertankers and container ships exceeding 200 metres in length during the last two decades. Rogue waves are believed to be the major cause in many such cases.
Mariners who survived similar encounters have had remarkable stories to tell. In February 1995 the cruiser liner Queen Elizabeth II met a 29-metre high rogue wave during a hurricane in the North Atlantic that Captain Ronald Warwick described as "a great wall of water… it looked as if we were going into the White Cliffs of Dover."
In a three period looking at a small fraction of the ocean surface these scientists found 10 waves that were at least 25 meters (over 82 feet) high. So these waves are like 7 story buildings or even higher.
Previously many scientists thought waves of such heights were extremely rare.
Objective radar evidence from this and other platforms – radar data from the North Sea's Goma oilfield recorded 466 rogue wave encounters in 12 years - helped convert previously sceptical scientists, whose statistics showed such large deviations from the surrounding sea state should occur only once every 10000 years.
The fact that rogue waves actually take place relatively frequently had major safety and economic implications, since current ships and offshore platforms are built to withstand maximum wave heights of only 15 metres.
This brings up an interesting question: Is the risk of dying in a trans-Atlantic or trans-Pacific crossing greater on a cruise liner or in a jumbo jet? I had assumed up until now that the risk was greater on an airplane. Now I'm not so sure. Anyone know if there are reliable numbers that can be used for calculating risks for ocean cruise ship crossings?
Aircraft and ships will become safer with time. One obvious strategy to adopt with ships is to develop technologies for spotting waves so that a ship's course can be altered to avoid them. Also, ships can be designed to be able to survive encounters with 30 or even 40 or 50 meter waves. But right now what is the safest way to travel?
Once it becomes possible to reverse aging and keep one's body in a permanently youthful state many people are going to become far more interested in reducing risks of accidental death. A risk that may seem low for an 80 year lifespan will seem much larger for an 800 or 8000 year lifespan. So the relative risks of driving, flying, and travelling on ships or trains is going to become a topic of much wider spread interest. Since the purpose of this web log is to think about issues that will be of increasing importance in the future it is not too early to start thinking about what is the safest way to cross oceans.
This is not supprising at all to anyone who has been in the Navy or knows people who have been in the Navy. Every Navy person I've known who has been out to sea has told me stories about the high waves splashing over the bow of the ship. One guy I know was on a carrier. He told me about the time that waves were splashing over the flight deck. The flight deck on a carrier is at least 60 feet high.
Interesting. Whenever i have had coversations about the ocean city-state (the floating Hong Kong), we have always discussed on how to make the city safe from 100 foot high waves. This is a real engineering challenge.
The question is: do these rogue waves occur along the equator where we want to build our city-state?
The proposed space elevator provides the economic stimulus for the ocean city-state.
Rogue waves are unlikely to occur near the equator. From what I've read, they tend to occur along with other waves. The equatorial "doldrums" have few waves because there is little horizontal wind (the hot air is rising as part of the global convection cells).
I've summarized some information about rogue waves here as part of my book on homesteading the ocean. There are a bunch of links there with more information, including theories about what causes rogues. I haven't added the info from this new study yet.
Patri, interesting site you've put together. You might want to take a look at the Mobile Offshore Base concept.
Are there severe weather effects, similar to storms and hurricanes, under the ocean? Perhaps the safest method will eventually be tunnels running along the surface of the ocean. Advances in automation and use of local materials will allow a tunnel building robot-complex to be sent off from New York and then allowed to just "do it's thing" for a couple months or years until it gets to England/ France.
Unless of course there's a great danger of underwater earthquakes which rip the tunnel up.
Maybe the 'safest' method of travel will be short hops out of the atmosphere a la SpaceShipOne. Earth is too chaotic & crazy a place to anticipate 100% of the time. :-)
Read about this in Discover, I think it was, the other day -- very interesting! Scientists had assumed that waves would only grow linearly -- most would disintegrate for a variety of reasons long before they came anywhere near 25m in height. The article discussed the rogue waves and how they were often the emergent property of multiple streams of water clashing together from different directions... The problem with rogue waves, evidently, is that they often run at an angle perpendicular to normal waves -- so if you orient a ship to head into the waves, you'll get broadsided (and holed or tipped, depending on the hull strength and ship size, etc.). The guy being profiled actually generated these in an indoor tank with wave generators and mathematical formulas.
Patti, I second Tangoman’s praise. Interesting project.
Does anyone have info on domed living? Alaska and Canada might be much more popular if the residents could occasionally experience a summer climate.
TangoMan - Our design bears some definite similarity to the MOB, as they are both meant to solve the same problem (creating a big stable platform). I'll make a note to add it in the engineering section.
Brock - there is little weather under the ocean. Currents often shift, but they are weak compared to waves. As you mention, underwater earthquakes and landslides are a worry. We discuss underwater living a little.
I do not think that rogue seas are confined to the oceans. They are well documented in the Great Lakes of North America. They do have in common the big storms, big waves, and harmonic resonance in the waves. And of course, loss of ships.