Why do cruise ships sink

They are also designed to withstand waves as high as 50 feet and some - especially those designed for Arctic and Antarctic voyages have re-enforced hulls to avoid breaches due to ice. While sailing ships have very deep keels, often with a heavy weight on the end to keep it stable, cruise ships are generally rounded bottoms with usually no more than 30 feet of the vessel below the surface of the water.

For instance, the Norwegian Bliss, has a Additionally, by design, many of the heaviest portions of the cruise ship will be found below the waterline such as the engines, fuel tanks, cargo, and of course the ballast tanks. This helps to ensure that even though the ship may appear to be top heavy due to the towering decks far above the water This allows the ship to maintain a level of stability that is both comfortable for the guests as well as safe for operation.

In , the New York Times did a study and found that between and , 16 cruise ships have sunk, with most being in inhospitable waters doing adventure cruises such as visiting Antarctica or smaller vessels that got caught in sudden storms such as the Estona, which sank in killing more than people in the Baltic Sea.

As a first time guest on a cruise ship you might think that capsizing is something that you need to worry about but considering that cruise ships are constantly sailing the ocean, carrying as many as 30 million passengers in , the 16 cruise ship catastrophes mentioned above present only a minuscule chance that you will experience a tragedy on your next cruise.

Any one of these can result in your cruise ship being adrift at sea except running aground. However, with the exception of other circumstances such as storms, or when the hull gets punctured due to running aground on rocks, these will generally not be life threatening for most guests.

For the most part, storms can be easily predicted due to the excellent weather prediction technology we have access to today. However, there are occasionally rogue waves that can cause significant danger to a cruise ship. These waves, sometimes measuring as high as feet tall, are extremely rare and even if your ship experiences one, it is unlikely to cause your cruise ship to capsize or sink.

With a properly trained cruise using modern technology - which all of the major cruise lines such as Holland America Line, Royal Caribbean, Princess, Norwegian Cruise Lines, and Carnival all have at their disposal, the bridge crew will be able to detect a rogue wave minutes or more before it poses a risk to the cruise ship.

They can detect these monster waves through high-resolution radar or LIDAR that can sense the movement of wave patterns around the ship. While it doesn't sound like much warning, even a few minutes of advance notice can be enough to steer the ship so it encounters the wave bow first instead of to the side.

No encounter with a rogue wave will be a pleasant experience, most cruise ships will be able to survive an encounter if faced head on, bow first. Despite this, there will still be significant damage to parts of the ship such as windows, furniture, and other loose items that will go flying should this happen.

To a certain degree, cruise guests are limited in what they can do to protect themselves since they might not even know there is a problem until it is too late. The Express reports that colliding with an object in the water can cause a cruise ship to sink. But weather can also threaten the stability of a cruise ship. However, combined with waves caused by wind, that wind could feasibly cause a ship to capsize.

Rogue waves, mechanical failures, and human error can also leave even large cruise ships vulnerable. Want to know how many cruise ships have sunk? Good luck finding a straight answer. The New York Times notes that nobody systematically collects data on collisions, fires, evacuations, groundings, and sinkings of cruise ships. In fact, the only person who does seem to track everything is sociology professor and cruise enthusiast Ross A. Klein, who operates a site called Cruise Junkie. Cruise Junkie reports that dozens of passenger ships sunk between and , according primarily to reports by English-language news sources.

All floating bodies have a metacentric height , that is defined as the vertical distance between the metacentre M and the vertical centre of gravity G. For ships, the vessel will remain relatively stable as long as this quantity remains positive.

In the event it becomes negative, the vessel can capsize with the smallest of forces. The metacentric height GM is directly related to a quantity known as the period of roll. This refers to the time that an oscillating body will take to come back to the original position of stability. Vessels with very large values of GM will instantly reach an upright position, which can cause damage to the equipment and machinery owing to the large forces exerted.

On the other hand, very low values of GM will have extremely high periods of roll. In this case, the vessel has a high chance of taking on water through the deck. Thus, if the GM moves out of the safe region due to various conditions, there is a chance of the vessel sinking. Due to the large unobstructed open space found in the ocean, wind speeds can reach the regions associated with typhoons or hurricanes. This can create massive waves that are able to capsize vessels.

Vessels can sink due to a few main reasons- wind and other forces forcing the ship to lean at dangerous angles to the port or starboard sides, waves on the deck adding weight to the vessel and forcing it lower into the water, or waves crashing into the side of the vessel and causing flooding.

All these reasons force the vessel to take on water, which eventually leads to it becoming unstable and susceptible to sinking by the smallest of disturbances. Fatigue , negligence and simple mistakes all contribute to a number of disasters at sea. These occur when ships are under-manned, have crews that are fatigued or are not properly managed.

As a result, simple avoidable errors are prone to occur. For instance, obstacles that float can get entangled in the rudder and propellers or can damage the hull. If not spotted in time, the vessel can collide with them.

In addition, if engine room measurements and adjustments are incorrectly made, there is a chance of the ship sinking due to a lack of thrust. It is important that shipping and passenger lines take efforts to keep the crew well-rested and ensure that the vessel is adequately manned at all times.

Sometimes, a wrong judgement regarding technical aspects can lead to the stability of the vessel being compromised. On the open ocean, visibility can sometimes be low owing to mist or fog. In addition, waves can make it difficult to detect floating objects that may pose a danger to the vessel. This is where modern equipment comes in, to guide the officers in the bridge in ensuring stability. However, incorrectly calibrated equipment is extremely dangerous, since the crew may use them to make key decisions.

In general, all equipment is to be routinely monitored and checked for accuracy at regular intervals. Although the preferred time interval between checks should be every thousand kilometres of the open sea or ocean sailing, cuts on spending can force companies to skimp on essential services. This can result in dangerous consequences that may cause the vessel to capsize and sink.

Ships stay at sea for extended periods, often returning to ports once or twice in a month or so for loading supplies and refuelling. Corrosion, metal fatigue and prolonged exposure to harsh conditions can warp and damage the vessel. Without regular maintenance, there is a high possibility of an accident occurring. For instance, the marine diesel engines that power modern vessels have extremely high ranges of operations RPMs. Under these conditions, the propeller shafts , rudders and propellers themselves can get damaged.

In addition to vibrational loads , high-speed propellers are susceptible to cavitation, that occurs due to the boiling of water near the surface of the propeller. Thus, regular check-ups are required, else there is a chance of the propulsion systems getting damaged. In general, small components are often the first to wear away, and thus comprehensive overall maintenance must be carried out diligently.

On average, ships with a lifespan of ten years have their full overhauls once in two to three years. If not carried out properly, it is possible that systems fail, leading to the vessel capsizing and eventually sinking. During the world wars of the early and mid-twentieth century, hundreds of ships and vessels were sunk.

Torpedoes, underwater mines, depth charges, artillery fire etc. In addition to the actual wartime casualties, there continue to be accidents that occur because of undiscovered mines or floating charges that are still armed and highly dangerous. Attack On Pearl Harbor — Credits: wikimedia.

In most cases of wartime sinking, torpedoes or explosives were used to rupture the hull, allowing water to flood the holds and drag the vessel down.