### vehicle | ship:

Submarine
* Many submarines have a shape which can be described as prolate spheroid.
* Some submarines can also fire antisubmarine missiles from the torpedo tubes
  - carry pure oxygen
  - run on diesel engines
* also carry mines to deny sea areas to enemy surface ships or submarines.
* are albums
  - among the most complex structures built by man
* are capable of dives
  - sinks
  - combat vehicles that make a significant contribution to our national defense
* are located in oceans
  - shipyards
  - made of steel
  - powerful weapons and their torpedoes can inflict great damage
  - submersibles
  - warships
* can carry torpedoes, cruise missiles, and mines for use in time of conflict
  - hide under the water
* float in ocean, easily changing their depth.
* generally use radar only on the surface when leaving or entering port.
* have an inner and an outer steel shell, called a hull
  - to be specially designed to withstand high pressures when they are deep underwater
  - decks
  - fireplaces
  - floors
  - hubs
  - lenses
  - periscopes
  - readsides
  - ribs
  - room light
  - rudder blades
  - sections
  - sonars
  - vents
* military vehicle
  - vessel used for operations on the sea surface and below the surface
* move in a straight line in any direction.
* rise and dive by filling large tanks with seawater.
* sink or float as they pump water in and out.
* use a similar principle to control their buoyancy, as do some fish
  - sonar in order to steer around obstacles and avoid hitting fish and other submarines
* use sonar to find objects under the water, including other submarines
  - locate other large objects and to find the depth of the ocean floor
* vary their weight by adjusting the amount of air in the ballast tanks.
+ Warship, Modern warships: Ship types

### vehicle | ship | submarine:

Attack submarine
* Many attack submarines can also deliver mines.
* Most attack submarines can carry and lay mines.
* are submarines.
* carry torpedoes to fire against enemy ships and submarines.

Modern submarine
* are able to dive and surface due to the invention of bouyancy tanks
  - very much quieter and radiate very little noise except at very high speeds
* can fully submerge in less than a minute
  - stay submerged for months at a time
  - travel faster submerged than they can on the surface

### vehicle | ship | submarine:

Nautilus
* are found in the South Pacific and Indian oceans
  - sexually dimorphic and reproduce by laying eggs
* are the only Cephalopods with an external shell
  - cephalopods who have an external shell
  - extant cephalopods which have an external shell
+ Nautilus, Natural history, Reproduction and lifespan
  * Nautiluses are sexually dimorphic and reproduce by laying eggs. Females spawn once per year and regenerate their gonads, making nautiluses the only cephalopods to repeat reproduction. The lifespan of nautiluses is about 20 years, which is exceptionally long for a cephalopod
  - The shell: Cephalopods :: Living fossils
  * Nautiluses are the only cephalopods who have an external shell. This is an ancestral or basal, feature. The animal can withdraw completely into its shell. It can the close the opening with a leathery hood formed from two specially folded tentacles. It is pressure resistant, but will implode at a depth of about 800 m. The innermost portion of the shell is pearlescent, blue-gray

Nuclear submarine
* are able to stay underwater virtually as long as they have food
  - among the most complex structures built by man
  - compact vessels with controls and perils spread throughout
* depend on their reactors to replenish their air supplies.
* have elaborate listening systems.
* produce their own air and drinking water.