## Thursday, December 7, 2017

### How Does the Largest Ship In America's Navy Stay Afloat?

How Does the Largest Ship In America’s Navy Stay Afloat?
I was watching the news one day and saw that the United States Navy just introduced the largest aircraft carrier in the world, the Gerald R. Ford. I immediately thought, how in the world does this ship float? The tonnage of the hull itself is around 100000 tons [1]. This equates to approximately 90909090kg. This massive vessel must have a buoyancy force bigger than any other man-made ship. I set about looking at our buoyancy force equation to see how the ship remains afloat with such an extreme force of gravity. I looked up the displacement of the vessel, which is how much water it displaces while in the water. The maximum displacement of the Gerald R. Ford is 110000 short tons as reported by All Hands, the magazine of the United States Navy [2]. A short ton is equivalent to 0.91m^3 and so the aircraft carrier displaces 99790m^3 of water. Using 1020kg/m^3 as the density of seawater, the buoyancy force then equates to Fb= (1020kg/m^3)(9.8m/s^2)(99790m^3) =997500840N. This enormous buoyancy force is what keeps the enormous ship afloat. This means that the ship can carry a vast amount of resources such as: aircraft, personnel, and a nuclear reactor, in addition to its already colossal mass. The force of gravity on the ship itself without including any of the things stated in the previous sentence is only 890909091N, which is vastly smaller than the maximum buoyant force on the ship. The maximum amount of mass the ship can carry is then 10876709kg. This should be more than enough to accommodate the supplies, and other resources the ship must carry in its duty to serve the Navy. Although the carrier will probably carry that much weight, it is astounding that humanity basically created a floating city. It is amazing to see that such titanic structures use basic physics in their creation. Physics never escapes us as its laws apply to all matter on Earth.

[1] Miller. Building a Giant: Gerald R. Ford. October 11th 2013. http://www.thefordclass.com/doc/Ford-fact-sheet.pdf

[2] READY FOR THE 21ST CENTURY Gerald R. Ford (CVN 78) is the first new design for an aircraft carrier since USS Nimitz (CVN 68). http://www.navy.mil/ah_online/ussford/