how does a ship's engine work?

Question

does the large ocean liners and cargo vessels use two stroke or four stroke engines?

Answer 1

most modern ships use electric motors to turn prop. the motors are supplied power from electric generators powered by very high horse powered diesel engines

Answer 2

The trend now a days is to use two stroke diesel engines.
The ships propeller should turn slowly so that losses due to water splashing (eddy currents) are minimum. In two stroke engines, the engine fires every second stroke, whereas in four stroke it fires once in four strokes. So 2 stroke engines can be designed to run very slowly (100 RPM or so) and yet be powerful enough, to move a big ship. They are directly coupled to the propeller. If 4 stroke engine is used, a reduction gear will have to be used to slow down the propeller, and this means more weight on the ship.Slow speed also allows the use of cheaper fuel, which requires more time to burn. Also, vibrations and wear/tear is less in 2 stroke engines.

Answer 3

Steam turbines are used to generate electricity which turns the prop shaft.
Using steam is a very effficient way to use fuel and electric motors can rotate at very high speeds so reducing the need for gearboxes as with some more convetional ships.
Some ships use nuclear plants to generate this steam rather like a nuclear power station.
As you proably are aware, steam was used originally to drive ships in times gone by.
Once the internal combustion engine was developed, ships used two stroke engines, and to reverse the ship they would stop the engine, alter the magneto or injection pump position and start the engine up in reverse.
Deisel for most medium sized ships is the preferred method for moving ships now and they have some very very big engines that are incredibly slow revving.. They generally have very long strokes and big bores providing maximum torque which can be turned into movement at the propellor.

Answer 4

Large ocean liners and cargo ships are powered by steam turbines. The steam is generated in oil-burning furnaces that contain a large bank of water-filled steel tubes leading to boilers that separate out the steam. Turbine exhaust steam discharges to condensers that recover the "fresh water" for reuse while creating a partial vacuum that expands the steam even more providing maximum power and fuel efficiency. Much older seagoing ships often used triple expansion steam engines that had such large pistons for the low-pressure stage (steam well expanded) that four men could play cards on the steam piston (when cooled and disassembled!). Of course fairly large excursion ships do use very large diesel engines. Smaller personal cruise ships often use automotive type four stroke gasoline engines.

Answer 5

Mostly they use deisel motors to create electricity and pump steam. But turning the big screws requires a steam engine. Bigbig huge boilers make steam out of filtered seawater wich is pressurized and pumped to the steam engine wich turns the screws wich make the ship go. Oh to answer your question, the steam engine is a two-stroke process. The deisels are four.

Answer 6

4 stroke.