On Wednesday night, the Royal Caribbean cruise ship, Anthem of the Seas, made it safely back to its berth in Cape Liberty in New York harbor, a bit battered, but generally in good condition. Her roughly 4,500 passengers disembarked after a harrowing cruise to nowhere. The obvious first lesson of this unfortunate voyage is that a winter cruise from New York harbor around Cape Hatteras may not be such a good idea. The weather can get very rough. In this case, extremely rough. The captain reported wind speeds of 150-160 knots (172-184 mph), wind speeds comparable to a Category 5 hurricane. There were also reports of 30-foot waves. The Anthem of the Seas was in serious danger.
Remarkably, the ship did just fine. The propellers kept turning. The lights stayed on. At the height of the storm, passengers in their staterooms were able to watch the Super Bowl without interruption, which was good news at least to Broncos fans. The ship incurred damage but it was reported to be superficial. There were no serious injuries to passengers or crew. As uncomfortable and scary as it must have been for all aboard, the ship; all eighteen decks of balconies, glass, and railings; weathered the storm. No doubt the captain, officers, and crew deserve much credit, but so too does the ship.
This matters because there have been many who have stated, matter of factly, that modern cruise ships are unseaworthy, unstable and simply unsafe. In the NOVA program, "Why Ships Sink," Allan Graveson, Senior National Secretary, Nautilus UK, a trade union, says, "These ships now are being built in such a way that they are inherently unstable. It is a design issue." The basis of Mr. Gravesonís assertion is unclear but it hasn't stopped him from repeating it.
Jim Walker, a maritime lawyer who specializes in the cruise industry and writes the popular blog, Cruise Law News, also expressed his opinion. In a blog post, "Are Cruise Ships Dangerously Top Heavy?" he writes:
"I do not pretend to be a naval architect. I studied English and History at Duke. It remains a mystery to me how jumbo jets can take off or huge ships can even float. But you donít need to be an expert to have an opinion on this issue. Mr. Sheperd reminds us of the old saying in boat building, "if it looks right, it is right."
Well, these cruise ships donít look right to me. They look like condominiums ripped out of Collins Avenue on Miami Beach and placed on a barge. They look eager to tip over."
The "Mr. Shepard" that Walker refers to is another blogger who also opined: "Why Mega Cruise Ships Are Unsafe."
The truth is that modern cruise ships do look ungainly and top-heavy. They look like layer cakes with way too many layers. Containerships stacked high with containers or the boxiest Pure Car Carriers look positively dainty next to the modern cruise ship behemoths.
Of course, opinions are not facts and appearances can be deceiving.
I am a naval architect and I know that one cannot calculate a ship's stability simply by the ship's appearance. Stability depends on many factors - the ship's vertical center of gravity, the moment of inertia of the waterplane, the area under the righting arm curve, windage, free surface and so on. It is not enough to say, "Gee, that ship looks top heavy." Likewise, to suggest that the ships are inherently unstable by design is just silly. Passenger ship design and stability are carefully controlled and regulated.
All this is easy to say, sitting in a heated office ashore. But are those of us who claim that there is nothing to worry about, that cruise ships are stable and meet all the regulations, are we also just expressing our opinions? Are our opinions supported by physics and engineering? The Prussian Field Marshall Helmuth von Moltke the Elder said that "no plan survives the first contact with the enemy." Likewise, ship designs that work on paper donít always survive a storm at sea.
The recent encounter between a modern cruise ship and major storm was a test, not a calculation or a simulation but a full-scale blowout trial in highly dangerous conditions. It was a test that probably could and should have been avoided, but proved interesting and revelatory, all the same.
The bottom line? The Anthem of the Seas survived. No one died or was seriously injured. The ship made it into port under its own power. This is not to say that all cruise ships under similar circumstances would necessarily have done as well, or that other things could not have gone seriously awry. But, in this case, the critics were proved wrong. A brand new cruise ship, as high sided and ungainly as any of her sisters, survived the worst winds and seas.
So, when the doubters suggest that cruise ships are unstable or unsafe, the right answer may be "they are a lot more seaworthy than they look."
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