1. State concept & function of Main propulsion plant equipment of Main propulsion plant?

a.   Main Engine

-Generates mechanical energy to turn a ship's propeller

-Kinds of following main engine can be used: Steam engine, steam turbine, gas turbine, diesel engine, and “generator - motor”

-Diesel engine is mostly used nowadays. Besides this, on modern ships newly manufactured with large power, the steam turbine propulsion plants are being developed.

-In the marine propulsion plant, one or more main engine can be used.

b.  Propulsion equipment

-Transforms mechanical energy of the main engine into thrust force when maneuvering.

-The oldest type of mechanical propulsion for ships is Jet propulsion.

-Paddle wheel was used on steamers until about 1850.

-Nowadays, screw propeller was used on all ship with advantage of high efficiency and safe working.

-There are two common kinds of screw propeller used in the marine propulsion plant, they are:

+ Non controllable - pitch propeller

+ Controllable - pitch propeller

c.  Driving equipment

-It is intermediate equipment to transmit power from a main engine to a screw propeller

-Driving equipment consists of: Shafting, flanges, split muff coupling, clutch, and reduction gear.

d.  Main boiler

-Its duty is to supply steam (with high pressure and temperature) to steam engine, steam turbine and other auxiliary machinery.

-Main boiler is used only on steam ship.

e.   Conveyance equipment

-They are used to convey working substance to a main engine. They consist of steam tube, gas tube.