Nature

Published on June 3rd, 2011 | by Yellow Magpie

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Rogue Waves: The Monster Of The Seas

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Freak, monster, and killer are just some of the names attributed to rogue waves.

Ever visit a fishing harbour and notice the big trawlers that have rather large dents in their bows? Were they the result of hitting other ships? No, these dents are caused by powerful waves, rogue waves.

Rogue waves are highly dangerous. They can sink any ship almost instantly, irrespective of size. There have been several documented cases of supertankers being split in two by rogue waves  quickly sinking to the bottom of the sea.

Undoubtedly, the most frightening aspect of these monster waves is the fact that they can occur in any water irrespective of the conditions. Even if the water is dead still, rogue waves can make an appearance. Freaks waves are not the result of tsunamis, or earthquakes. They are entirely independent and many aspects of them are still a mystery.

Walls Of Water

Many people who are fortunate to survive the traumatic experience claim to see a huge wall of water. Because rogue waves contain such an enormous amount of mass, if hit directly the ship has little chance of remaining afloat. It is thought that rogues occur so frequently that perhaps one ship a week makes its way to the bottom of the ocean because of them.

There are no concrete explanations for what causes these freak waves however several theories have been postulated. Some more credible than others.

The Stuff Of Legends

Originally freak waves were confined to legend and myth. Seamen often talked about seeing mountains of water, and incredibly powerful waves. However, the scientific community still remained sceptical about the presence of these rogues. Previous to the acceptance of monster waves, scientists used linear equations which meant that the size of waves were limited by the conditions.

According to this linear model, rogue waves were not possible. The problem with the linear model, that scientists and meteorologists use, is that it vastly underestimates the frequency of these monster waves. Going by this method, the chance of freak waves occurring are so slim that they would only happen once every ten thousand years or so.

From Myth To Fact

The strongest ships are only designed to handle 15 metre waves. This foolhardy method of shipbuilding and the limitations of the linear prediction model were shown up for all to see on New Years Day, 1995. An oil rig called the Druaper Platform experienced a 25.6 metre rogue wave in a storm where the significant wave height was only 12 metres.

If the accuracy of the linear model was to be believed an event like this should only happen once every ten millennia. Scientists and meteorologists from around the world took note as this was the first time that instruments had measured a rogue wave.

The Deadly Cape Of South Africa

The hotbed of rogue waves is South Africa. Perhaps this should come as no surprise seeing as the Cape is one of the most dangerous places for ships.

All along its coast the wreckage of very large ships that have been destroyed by rogue waves is visible. Unfortunately, the Cape is in one of the busiest shipping lanes in the world with billions of euro worth of cargo. The last three decades have seen over 30 ships either sunk or heavily damaged in South Africa. All of these incidents were due to freak waves..

New Patterns And A New Model

After intensively pouring over data gathered on the South African shipwrecks. It was found that each wreck occurred on an ocean current, the Agulhas current. Scientists now had an explanation for these monster waves.

In South Africa it is thought that when this powerful current meets with wind and stormy swells head-on, freak waves are formed. Unfortunately, these conditions are very common in South Africa. But on the flip-side it meant that rogue waves could now be predicted.

It It Looks Too Good To Be True…

Other parts of the world seemed to fit into this South African model. Ships could now avoid rogue waves by plotting alternative courses.

The marine world was uprooted once more on February, 2001, on an Antarctic ship called the Caledonian Star. A huge 30 metre-high rogue wave with an equally gigantic trough smashed into the ship. The windows of the bridge were completely smashed and the navigation instruments and communication instruments were destroyed leaving the ship highly vulnerable. Luckily for the crew and passengers the ship still had its engines running.

A cruise ship, MS Bremen, at the same time and in the same location, was also hit by an unpredictable freak wave. However, unlike the Caledonian Star, the wave caused severe damage and the ship was left adrift, powerless, its side facing into the storm. Just one large wave would have been enough to sink it in this position. For two hours it rolled lifeless completely at the mercy of the ocean until repairs were successfully carried out and power was restored.

No currents that could cause rogue waves exist in the Antarctic. The simple way of predicting these waves is no longer valid.

The Search Continues

The European Space Agency satellites are being employed to scan the world’s oceans, using radar to detect rogue wave patterns. Project MaxWave is so sensitive that it can pick out individual rogue waves. However, the satellites are only there for a tiny portion of the time. In just three weeks ten waves of roughly 26 to 30 metres were recorded in the deep ocean.

Quantum Mechanics And The Non-Linear Model

Eventually, a new theory began to gain credibility and it came from an unusual source, quantum mechanics.

Using a modified version of the non-linear Schrodinger Equation, which is used to predict changes in the quantum world, it began to emerge how these monsters occur.

It is now known that deep water rogue waves occur when one wave absorbs energy from the waves in front and behind it. The rogue is unstable and feeds off the energy getting enormous while decreasing the size of the waves feeding it.

The Common Factor

Unlike normal waves, rogue waves are not smooth relatively gentle inclined slopes. Instead they are vertical walls of water which makes them very dangerous to ships as they are breaking waves. Therefore, the water is falling vertical on top of ships from a great height. Normal waves exert a force of roughly one to two tonnes per square metre, 12 metre storm waves can exerts forces in the region of six tonnes per square metre.

Rogue waves though are very different monsters. They exert huge forces of up to 100 tonnes or more per square metre. Current ships just simply cannot withstand these forces.

We know now that rogue waves can occur, with little warning in deep water away from currents. The only reasonable thing to do now is redesign ships so that they can deal with the huge forces exerted by these monsters.

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The Power of the Sea: Tsunamis, Storm Surges, Rogue Waves, and Our Quest to Predict Disasters is an absorbing read that delves into the subjects of tsunamis and other water-based natural events and reveals the frightening effects that our increasingly warmer oceans are having on our planet.

You can obtain here The Power of the Sea: Tsunamis, Storm Surges, Rogue Waves, and Our Quest to Predict Disasters from Amazon.

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For those living in Canada you can obtain The Power of the Sea: Tsunamis, Storm Surges, Rogue Waves, and Our Quest to Predict Disasters from here.

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For Germany: The Power of the Sea: Tsunamis, Storm Surges, Rogue Waves, and Our Quest to Predict Disasters.

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For France: The Power of the Sea: Tsunamis, Storm Surges, Rogue Waves, and Our Quest to Predict Disasters.

About the Author

Yellow Magpie

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