Tuesday, January 17, 2012

Cruise ship stability concerns after Costa Concordia accident

The recent cruise ship accident in Italy where Costa Concordia ran aground a reef raises concerns among vacationers whether it is safe to travel by a cruise ship or not. The Costa Concordia deviated too far from her usual route and hit the reef of the island of Giglio. Shortly after running aground the rock, her hull suffered from severe damage that allowed massive amount of sea water to enter the ship. She capsized rapidly forcing the passengers and the crews of the cruise ship to abandon her for safety. Until now the rescue works are still going on to search for the survivors trapped inside the sunken hull and superstructure of the ship.
Cruise vessel Costa Concordia
Cruise Ship Costa Concordia
Costa Concordia was an Italian style cruise liner sailing the West Mediterranean Sea usually on a 7 night cruise visiting ports of Civitavecchia, Savona, Marseille, Barcelona, Palma De Mallorca, Cagliari, and Pallermo.
Cruise ship and passenger ship have been designed by naval architects to have positive stability with the metacentric point (M) is above the center of gravity (G). If the point of metacenter is at the same height or below the center of gravity, the ship is said to be in neutral or negative stability. Naval architects who design ships know this initial stability criteria. They will always design ships including the cruise ship Costa Concordia and Oasis of the Seas with positive metacentric height even when they sail with full passengers on board and through rough seas.
Watertight bulkheads
The case will be different when the hull plating of a cruise ship suffers from severe structural damages that cause all or significant percentage of her watertight enclosures or compartments to loose their ability to keep the vessel remain afloat in upright position. Watertight enclosures or bulkheads have been constructed in merchant ships to protect them from drowning. When one of the compartments of a ship is flooded with water, crews will shut the hydraulic doors that connect the compartment with other watertight enclosures to prevent water from flowing into the whole area of ship's hull thus preventing the ship from sinking.
Balancing technique
It is also possible to flood one or more compartments of a damaged cruise ship to restore her to upright position when huge amount of seawater entering a certain proportion of the ship's hull and threatens to capsize her. For example, if a ship collides with a rock at her hull causing sea water to enter the front compartment, another compartment at the stern area of the ship can also be flooded with water to balance her position.
Advanced Navigational Equipment
Today, modern cruise ships such as Costa Concordia from the Italian cruise line company - Costa Cruise, the Oasis of the Seas and the Allure of the Seas - operated by Royal Caribbean International, have been equipped with advanced navigational equipment that are guided by satellites and radars. The captain of Costa Concordia cruise liner and her crews have more than enough technology to sail their vessel safely even through uncharted waters.
Judging from the nature of the accident where Costa Concordia deviated too far from her usual route in calm weather, the most possible causal factors of this accident would be the failure of the navigational instruments at the bridge of the ship or the mistakes done by the captain and the other crews of the ship - or both. by Charles Roring
related articles:
Stability of cruise ship;
Cruise Ship and Passenger Ship

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