Serious question: Why don’t Navy ships tip over? You wouldn’t think that such a narrow V-shaped hull would be nearly as stable as a wider U-shaped hull. And aircraft carriers look ridiculously top-heavy.
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ANSWERS: 4
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And better yet, they weigh so much how do they not sink? I think you have to be an engineer to answer questions like these. I hope you get the answer. I am curious too.
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It all has to do with placement of mass and centre of gravity. It's not so different than how a sailboat with a weighted keel, remains upright, while a wind in the sails is trying to tip it over. The keel's mass is located well below, resiting the wind's attempt to tip the boat unless the wind's strength or extra mass added above the centre of gravity exceeds what stabilizing force the keel exerts. What mass that you see of a ship, above the waterline is actually much less than what is present below it. Fuel, engines, fresh water tanks and ballast tanks are all located below the waterline, keeping the bulk of the vessel's mass low in height. A good analogy here is a canoe. Kneel properly in your canoe and it's stable. Stand up and you're going swimming.
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Actually, what you are thinking of is how they look just at the bow of the ship. The bow is shaped like that so that it can slice through the water. Once you get below the waterline and further aft, the hull get much wider. Consider the following pictures, the first is from an angle and it make the ship's hull (the USS George H. W. Bush in this case) seem quite narrow (http://tinyurl.com/3j3dsu). The second is an artist's rendering of what it will look like when if does enter service looking nose on (http://tinyurl.com/3ef7px). Finally we have a mostly nose on image of the Bush in dry dock (http://tinyurl.com/4vscto). Note how flat the bottom really is.
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Only the bow is V-shaped. Once you get more than about 1/4 of the ship's length aft of the bow, the hull is nearly flat. Unlike sailing ships and most small-craft, the bilge is NOT the bottom of a Navy vessel. Fairly far from it in fact. Long story short, the bottom of the ship has a lot of tanks; some ballast, some fuel. As a result, there is a LOT of weight down low and relatively little up top. Aircraft carriers have a HUGE hollow space above the waterline that is four stories high and runs about three-quarters the length of the ship and nearly the full width. Between the fact that the Hangar bay is light and the fact that there are HUGE tanks 20-35 feet below the waterline, carriers are pretty stable... as long as they are undamaged and the Engineering keeps her trimmed properly.
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