What percentage of cruises sink?
Can a cruise ship capsize? Dangers of luxury holidays at sea REVEALED
Though cruise holidays are built with relaxation in mind, the journey isn’t always smooth.
There are many obstacles cruise ships can face out in the open ocean, but thankfully the industry has contingency plans for all of them.
With rigorous safety standards across the board, cruise ships are some of the safest places to spend your hard-earned holiday.
The chances of your cruise ship capsizing or sinking are infinitesimally rare.
According to the New York Times, only 16 ships have sunk since 1980.
Cruise ship holidays: Can giant luxury liners capsize or sink?
Colliding with an object in the water can cause a cruise ship to sink, but all modern liners are fitted with exceptionally advanced technology to ensure they avoid any such object in their path.
When it comes to cruise ships capsizing, the warning signs are a little different.
Weather is the most hazardous condition to threaten the stability of a large liner.
Cruise ship Costa Concordia sank off the coast of Italy in 2012
Cruise ships have continuous contact with weather routing services to keep them safe
Many experts agree that wind alone cannot cause a cruise ship to capsize, but waves caused by extreme wind feasibly could.
Professional ship manager Neill Conroy from the Nautical Institute said: “By itself, no wind can cause any ship to capsize. However, the waves induced by a strong wind that lasts for an extended period can certainly cause a small ship to capsize, if the waves strike the ship broadside (or nearly so) under the right circumstances.”
But the chances of this happening are almost impossible due to the weather routing technology on board.
Mr Conroy said: “Cruise ships are much bigger, and have continuous contact with weather routing services to keep them safe.
“While they hate doing it, they will cancel a port visit if weather dictates. You have nothing to be worried about.”
Cruise ship Titanic sank in 1912 after hitting an iceberg
A rogue wave could also cause a cruise ship to capsize.
This type of wave is defined as greater than twice the size of surrounding waves, which comes often unexpectedly from a direction other than prevailing wind and waves.
A rogue wave is an extremely rare occurrence but can prove extremely dangerous to cruise ships in the open ocean.
In 2007 a Holland America cruise ship was hit by a 12m rogue wave near Cape Horn.
The ship withstood the giant wave but 40 people were injured with some needing hospital treatment.
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Why don’t cruise ships tip over?
If you have seen today’s mega cruise ships, you might have wondered why don’t cruise ships fall over? How are the mega ships (think Symphony of the Seas, Carnival’s Mardi Gras, and the much anticipated Icon of the Seas) able to accommodate the weight of 5,200, 6,680, and 7,600 guests?
With all that height above the water and not much below the water line, what’s keeping the ships upright?
Today’s modern cruise ships are amazing pieces of technology, maritime tradition, and innovation. That being said, a combination of design and physics is how they stay afloat.
When a cruise ship is designed, the assigned engineers are careful to keep the average density of the ship less than the average density of air. The reason ships float is because they weigh less than the weight of the water that they displace.
Looking at a cruise ship, there is a large amount of the ship above the water, and a small amount below the water. You’ll rarely see that portion, though; It’s most common to see during dry docks when the ships are completely removed from the water for maintenance.
So what forces are actually acting on the ship to keep it afloat?
The weight of the ship is pulling it down in the water. The weight is balanced by the buoyancy, which is pushing it up. And if the buoyancy is greater than the weight, the ship would continue to move upwards.
But to work out why the ship doesn’t tip over, we need to think about where exactly these forces are acting. Those points are the center of gravity for the weight, and the center of buoyancy for the buoyancy of the ship.
Point 1: Center of Gravity
If everything in the ship weighed exactly the same, the center of gravity would be right in the middle.
But the engines, machinery, fuel stores, and those sort of things weigh an awful lot more than the cabins and passenger spaces — think of venues like theaters and dining rooms, which are mainly just air and negative space.
This has the effect of dragging the center of gravity downwards. So, we know the center of gravity will be towards the bottom, lower half of the ship.
Point 2: Center of buoyancy
Cruise ships displace water equivalent to its own mass. The pressure of the sea pushes up against the ship’s hull in order to counter the downward force of its mass. Since water cannot be compressed, the combined forces create buoyancy.
For the center of buoyancy, we are interested in the stuff under the water, and to find the center of buoyancy, all we need is the center of the water plane area, which is just the middle of the part of the ship that’s under the water.
The buoyancy of an object on the water depends on its density. If the object is denser than water, then it will sink. If, however, it is less dense then water, it will float.
What keeps a cruise ship from sinking is an opposing upward force, or pressure, from the water. This upward force weighs the same as the water that was displaced, keeping it from sinking completely.
How the ships stay upright
Since we can calculate the center of gravity compared to the center of buoyancy, it comes down to a matter of managing weights.
But what happens when an external force, such as wind, comes along? Since the wind will likely push the ship on one side, why doesn’t it topple over?
Essentially, a cruise ship stays upright because they keep all of the heaviest equipment — like the engines and whatnot — below deck. This has the effect of keeping a low center of gravity and keeping the ship upright during unfavorable weather conditions.
In addition, the shape of a cruise ship’s round-bottom hull is wide, which helps it move through the ocean smoothly and with minimal drag. This is much more stable than a v-shaped boat hull.
Round edges also increase the ship stability, preventing the vessel from swaying and rocking and passengers- from feeling seasick.
However, the resulting stability means that cruise ships often move slower than boats with v-shaped hulls.
In addition, ships have something crucial for the ship’s balance, ballast tanks. They contain water that can be pumped from one side of the ship or the other. In case of an emergency or rough seas, it helps to keep the ship balanced, counter the waves and reduce rocking. A large cruise ship usually has several ballast tanks.
So the combined effect of a ship’s buoyancy, low center of gravity, and ballast keep the ship from tipping over.
The Lusitania Disaster
On May 7, 1915, the German submarine (U-boat) U-20 torpedoed and sank the Lusitania, a swift-moving British cruise liner traveling from New York to Liverpool, England. Of the 1,959 men, women, and children on board, 1,195 perished, including 123 Americans. A headline in the New York Times the following day—»Divergent Views of the Sinking of The Lusitania«—sums up the initial public response to the disaster. Some saw it as a blatant act of evil and transgression against the conventions of war. Others understood that Germany previously had unambiguously alerted all neutral passengers of Atlantic vessels to the potential for submarine attacks on British ships and that Germany considered the Lusitania a British, and therefore an «enemy ship.»
The sinking of the Lusitania was not the single largest factor contributing to the entrance of the United States into the war two years later, but it certainly solidified the public’s opinions towards Germany. President Woodrow Wilson, who guided the U.S. through its isolationist foreign policy, held his position of neutrality for almost two more years. Many, though, consider the sinking a turning point—technologically, ideologically, and strategically—in the history of modern warfare, signaling the end of the «gentlemanly» war practices of the nineteenth century and the beginning of a more ominous and vicious era of total warfare.
Throughout the war, the first few pages of the Sunday New York Times rotogravure section were filled with photographs from the battlefront, training camps, and war effort at home. In the weeks following May 7, many photos of victims of the disaster were run, including a two-page spread in the May 16 edition entitled: «Prominent Americans Who Lost Their Lives on the S. S. Lusitania.» Another two-page spread in the May 30 edition carried the banner: «Burying The Lusitania‘s Dead—And Succoring Her Survivors.» The images on these spreads reflect a panorama of responses to the disaster—sorrow, heroism, ambivalence, consolation, and anger.
Remarkably, this event dominated the headlines for only about a week before being overtaken by a newer story. Functioning more as a «week in review» section than as a «breaking news» outlet, the rotogravure section illustrates a snapshot of world events—the sinking of the Lusitania shared page space with photographs of soldiers fighting along the Russian frontier, breadlines forming in Berlin, and various European leaders.
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