Pearl Harbor The Japanese attacked “Battle Ship Row” in successive waves of attacks. Several key battle ships are highlighted here. USS Nevada USS Arizona.

Pearl HarborThe Japanese attacked “Battle Ship Row” in successive waves of attacks. Several key battle ships are highlighted here.

USS Nevada

USS Arizona

USS California

Pearl HarborThis overhead view shows the arrangement of the battle ships. Note the locations of the Arizona and the California.

Pearl HarborThe battle ship that suffered the most damage was the USS Arizona. A bomb ignited explosives on the ship. Over 1000 crewmen perished.

Pearl HarborWhere the Arizona sank would, in time, become the location of a war memorial. None of the Arizona was salvaged.

Pearl HarborThe California also suffered heavy damage, but not as extensive as the Arizona.

Pearl HarborIn spite of efforts to keep the California afloat, the ship sank three days after the attack on Pearl Harbor. Only the top-most part of the ship jutted out of the water.

Pearl HarborBut an analysis of the condition of the ship showed that it could possibly be raised.

Pearl HarborWhat causes a ship to sink is when water fills the air-filled hull. In the case of the California, Japanese torpedoes punctured the hull.

Pearl HarborIn other words, a ship floats because it displaces a volume of water equal to at least the weight of the ship. This gives the ship a density less than water.

Pearl HarborWhen a ship takes on water equal to the amount of water it displaces, then its density is at least twice that of water. Water has a density of 1.

Pearl HarborLet’s assume that the density of the sunken ship is twice the density of the ship when it floats.

Pearl HarborWhile water is removed from the sunken ship, its density changes, as shown in the rational function above.

Pearl HarborA graph of the rational function shows that at c = 1, the density of the ship is equal to the density of water. The graph of f2(x) = 1 represents the level where the ship’s density is the same as that of water.

Pearl HarborTo simplify the process, the California had air-tight compartments, allowing the water to be removed one section at a time.

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• To help reduce the mass of the ship, some of its heavier components were removed. The effect was to reduce the amount of water that needed to be displaced in order to raise the ship.

Pearl HarborReducing the mass changes the density equation.

Pearl HarborAs d increases in value, then the amount of water needed to refloat the ship decreases.

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• It took three months to rescue and raise the USS California. It had sustained a great deal of damage but was still usable. It would take close to two years to retrofit it and get it battle ready.

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• When it returned to the war, the California took part in these battles:

• Saipan and Guam• Leyte• Luzon• Okinawa

• These were pivotal battles that led to the defeat of the Japanese navy.

Pearl HarborWe cannot underestimate the heroic efforts to salvage the ships at Pearl Harbor.

“All this represented one of history's greatest salvage jobs. Seeing it to completion required that Navy and civilian divers spend about 20,000 hours underwater in about 5000 dives.”– Naval History and Heritage Command Web Site

Pearl HarborWhile the Japanese Imperial Navy may have overestimated the military impact of Pearl Harbor, they certainly underestimated the resilience of the U.S. Navy.