Parts of a Submarine

Late in the 15th century, Leonardo da Vinci made the first suggestion that an under water “ship” was possible. His idea is only represented in his drawings and no models were tested. Since that first idea surfaced submarines kept reappearing in history until they became refined enough to be viable war machines. World Submarine History Timeline prepared for NOVA by Captain Brayton Harris, USN (Retired) and author of The Navy Times Book of Submarines: A Political, Social and Military History, goes into great detail about the history of submarines.  

The large majority of submarines in the world are built for war. There are many smaller research submarines and submersibles in the world as well but they all have one thing in common: Limited space. Space is at a premium in these vessels so there is nothing aboard one of these ships that isn’t needed for survival. Even the extras like cards, chess sets and books are needed for good mental health.  

There are many thousands of individual parts in a submarine all doing their part to make it work. A temporary disabling of some of these parts will not cause the submarine to lose its integrity but a failure in the key parts of a submarine can be catastrophic.  

Pressure Hull  

The most important part of a submarine would be the pressure hull. It is the inner part of a submarine that protects the crew from the crushing pressures of the ocean while diving. This is the strongest part of any submarine. According to Science, How Stuff Works, “The hulls of nuclear submarines are made of HY-80, an alloy made from nickel, molybdenum and chromium.” When you see a submarine on the surface you are seeing the outer hull. It is water proof and provides that extra layer of protection for the crew.  

Ballast Tanks  

Ballast tanks are critical to a submarine because by using these it is able to submerge and rise to the surface at will. Ballast tanks are located between the inner and outer hull of a submarine. When a submarine needs to submerge it fills these tanks with sea water. This changes the buoyancy of the submarine. Special ballast tanks, located forward and aft, are known as “trim tanks.” They are filled with air or water allowing the bow or stern of the submarine to rise and sink.  


The earliest known submarines were propelled by human foot petals. According to New World Encyclopedia, “The first mechanically driven submarine was the 1863 French Plongeur, which used compressed air.” Later came battery power for running submerged and diesel power for running on the surface and charging it’s batteries. This type of submarine is known as diesel electric. The diesel motors do not drive the propellers but power electric motors that do. Submarines built since the 1950’s have nuclear power. Nuclear powered submarines, from World Nuclear Association, can stay submerged for extremely long periods of time. Everything the crew needs is provided by the nuclear reactor. Air, fresh water and electricity.  

Conning Tower  

Also known as the “sail” or “tower,” this is the control center of the submarine. A periscope is located in the conning tower so the submarine can remain completely submerged and still visually see what is on the surface. All of the submarine’s operating systems are controlled and monitored from the conning tower.  


Located on the bow and stern of a submarine are the hydroplanes. These work like the flaps on an airplane. As the submarine is propelled through the water the hydroplanes can be adjusted to make the submarine dive or surface. The vertical fin is the rudder, which turns the submarine right or left.


Modern submarines carry with them a wide range of weapons, from Shima Demon. They have conventional torpedos, missles, anti ship missles, mines, cruise missles and nuclear missles. The power of destruction empowered in a nuclear submarine is hard to believe. 


Submarines cannot visually see where they are going while submerged. They depend upon a lot of electronic equipment to accomplish this task. Submarines use GPS satellites, as in GPS 101 by Richard Lewis, SONAR, inertial guidance. GPS satellites can pin point a submarine’s exact location anywhere in the world. SONAR, from How Stuff Works, uses sound pulses sent out into the surrounding sea and listens for echoes reflecting back indicating any obstructions. The inertial guidance system uses gyroscopes that can tell direction and distance traveled but only for about 10 days.  

Life Support  

In the past, submarines had to surface regularly to renew their air supply and charge their batteries. Today’s nuclear submarines convert sea water, by electrolysis, to make oxygen and scrub carbon dioxide from stale air. They also make fresh water from sea water using electricity. Nuclear submarines have large stores of food supplies on board so they can remain submerged for several months at a time.  

Submarines have played a very important part in human history. They were the absolute terror of the seas in World War 1 and World War 2. Modern 21st century nuclear submarines are silently patrolling the seas protecting peace around the world.