Submarines

By using submarines, the German war machine was able to come close to America's shoreline and this surely pushed the u.s. To act

It did - one U-boat even sunk a ship in the St-Laurence Seaway, and many U-boat crews were startled by the ease with which they could torpedo ships close to the US shore until the ships' crews realised the value of black-out conditions.

When ever they were presented with targets of opportunity.

IJN subs were deployed for "fleet warfare", not merchant raiding. The costly job of sinking allied warships fell to the IJN sub fleet. It's estimated that IJN submarines sank less than 50 merchant ships during the war.

Yes, the above answer is correct. But I believe it was Winston Churchill's Rapport with the President of America, Franklin Delano Roosevelt, that led to the USA coming to the help of Britain and her Allies. At first it was lease-lend - helping with old ships, etc, but in return in Britain allowing America to set up facilities in British held territories. But, once Japan attacked Pearl Harbour, America were able to publically declare war - and America geared up to help Britain and the Allies in defeating Germany, and Japan.

A submarine has tanks that are called ballast tanks. When these tanks are flooded with sea water, the submarine sinks because the sub weighs more than the water it displaces. To rise again, the sub reduces its weight by pushing compressed air into the ballast tanks. The air forces the sea water out and sub returns to the surface. It maneuvers using its rudder and planes. A link is provided.

Almost everything in the ocean makes some type of noise. Further noise travels 5 times faster in water than it does in air and many time further. Submarines use listening devices known as passive SONAR to listen to the sounds of the ocean. It's a falicy that submarines make dangerous levels of noise. In fact a modern submarine is actually more quiet than the water that it displaces.

-sub

It floats and sink by changing its buoyancy. The primary method of controling buoyancy is the ballast tanks. The air is let out of them and is displaced by water. This gives the submarine negative buoyancy, which will get the submarine to submerge. By blowing or pumping air into those ballast tanks, the submarine becomes buoyant and rises to the surface.

It's not - the Russians have always had lower profile sails on their boats compared to Western boats. The Borei is a successor to the Delta-class submarine; the sail seems a bit longer, but the height is about the same as a Delta-IV.

The current-generation U.S.S. Virginia nuclear attack submarines cost between 1.8 and 2 billion dollars each, including the amortized development costs for designing the class (i.e. it costs about 1.4 billion or so to actually build the sub, but there were several billion in startup, R&D, and design costs for the class, which adds about .5 billion to each sub).

A typical non-nuclear attack submarine (such as the German Type 212) costs around $500 million, including the amortized development costs. Note that the typical non-nuclear attack submarine is usually about half the size (and a quarter of the displacement) of a nuclear attack sub.

The Allies referred to them to as U-boats a contraction of the translation of the German name for the vessels: Under sea boat or in German "Unterseeboot"

It stands for United States Ship

There is a stick type thing on the top where you aim down your sights and you squeeze it then you replace a new mag they are called. That's how you reload it.

It'll cost about 16 million around that. Better start saving!

Its the war on the water. During the battle of bunker hill.

passive margins

Ships would form a convoy in an attempt to reduce their vulnerability to enemy submarines.

true

No - most modern submarines, depending on type, have between 15 and 25 torpedoes aboard.

Their yields are about the same as most land based ICBM warheads or bombs dropped by airplanes: from 100 kiloton to 300 kilotons. Yields in the megaton range as were common in the 1950s through 1970s have been shown to have few real military uses and more damage can be done using several bombs of less total yield at lower cost using warheads in the 100 kiloton to 300 kiloton range.

Deaths will depend on too many variables outside the characteristics of the warheads/bombs themselves, including the target, burst height, availability of shelters, emergency preparedness of the population, etc.

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The Buoyant force depends on the equation Fb=mfg where Fb is the buoyant force, mf is the mass of the fluid (water) that is displaced by the body and g is the Earth's gravitational constant 6.673x10-11Newton Meters squared per kilograms squared (Nm2/kg2)

Submarines use buoyant forces and gravity to move up and down with in the water. When the Buoyant force is less than the Earth's gravitational pull on the submarine, it sinks, when the buoyant force is greater than the Earth's gravitational pull on the submarine, it rises. Once the submarine is already submerged, the buoyant force is constant.

Submarines adjust the Earth's gravitational pull on it by filling the space in between the inner walls and outer walls with water and/or gasses.

With out buoyant forces, the submarine would never return to the surface of the water.

Modern submarines use what's called an Oxygen Generator (aka, "The Bomb") to generate O2 and compress and store it in large tanks outside the pressure hull. It's bled into the boat as necessary through valves at different points on the boat. O2 content is strictly regulated.

The O2 generator uses a simple process of electrolysis to separate Hydrogen and Oxygen molecules from distilled water. Since both gases are extremely volatile, the process is closely monitored when in operation. The oxygen is separated and stored as I said before; the hydrogen is bled overboard as mini bubbles through a diffusion tube into the ocean.