What are Submarines ?

In 1776 a US inventor (David Bushnell) built a submarine that was used in the American Revolution. Later on in the year 1800 another American inventor (Robert Fulton) built the Nautilus. This submarine was small and was used for attaching explosives to ships

Submarines use sonar when they are submerged to obtain information on enemy targets, underwater terrain, and other hazards.

inventors had come up with subs that could run on a battery-powered electric motor (for underwater) and diesel engines (for surface travelling). These submarines were used in both World War I and World War II.

This is classified as well. However, U.S. nuclear-powered submarines can go faster than 23 miles per hour, which is 37 kilometers per hour or 20 knots (nautical miles per hour) underwater.

In 1954, the US Navy used the first nuclear-powered submarine

Surface Tension: The shape of the tear drop hull design allows a submarine to slice cleanly through the ocean when there is water on all sides - as well as house sensitive sonar equipment

In order for a submarine to stay submerged (underwater) it has special compartments called, ballasts. These huge tanks fill up with water when the sub wants to sink

When the submarine wants to rise, the water in the ballasts is let out. This makes the vessel lighter so it rises. A sub also has a propeller on the back of it. This pushes it at various speeds.

it uses energy to generate the bow wave and wake. and then less energy is put into propulsion. Designs for World War II vessels and the first nuclear-powered submarine, USS Nautilus, had narrow bows to move faster on the surface than they did underwater.

the one submarine that cannot go underwater is the submarine sandwich? It would get really mushy and taste disgusting.

in 1870 Jules Verne wrote the classic novel, 20,000 Leagues Under the Sea?

specialized submarines can reach depths of 4,498 meters (14,760 feet)?

A submarine has access hatches to bring in outside air when in port, and a snorkel mast to bring in air while submerged at periscope depth. Once submerged below periscope depth, equipment continuously clears the air of contaminant and oxygen-generating equipment to further replenish the air.

Navy submarines have two escape trunks, which are like air locks and can be used as escape routes. You would put on a life preserver that has a hood that provides a bubble of air to breathe, and then enter the escape trunk.

nuclear submarines can hold up to 100 crew members?

the long narrow body of a sub is called, the hull?

The lower hatch is shut, the trunk fills with water and comes up to sea pressure. Then the outside hatch is opened, and you float to the surface.

when a submarine needs to see what's going on above the water, they use a periscope? This is like a single binocular-like eyepiece.

The Navy has rescue submarines called Deep Submersible Rescue Vehicles (DSRV), as seen in the movies, Hunt for Red October, or Gray Lady Down. They can attach to the escape trunk of the sunken submarine and take on the crew. The next generation rescue system is called the Submarine Rescue Diving and Recompression System

The Navy has two official museums dedicated to submarines and undersea warfare:

U.S. Navy Submarine Force Museum - Includes the USS Nautilus, USS George Washington and USS X-1. Groton, Connecticut.
Naval Undersea Museum: Keyport, Washington.

the submarine has a "raised deck?" When the vessel rises to the surface, crew members can stand on the top of it.

On 5 September 1914 Royal Navy ship HMS Pathfinder was sunk by a torpedo from a German submarine at the Firth of Fourth. Casualty figures for the attack are disputed but by one estimate only 18 of 268 people on board survived.

This attack came as a shock to Royal Navy commanders who had been divided over whether it was possible to sink a large surface vessel using a submarine.

Although their exact policy varied throughout the war the German U-boats racked up a total of 12,850,815 tons of shipping sunk.

The highest total for a single year was 1917, when unlimited submarine warfare resumed and 6,235,878 tons was sunk