1. Marine Engineer’s Duties

Engine room of a merchant ship has the following personnel: Chief Engineer, Second Engineer, Third Engineer and Fourth Engineer.

All ship engineers are responsible for keeping in order all the machinery.

The Chief Engineer is free of watch. His main task is to ensure general leadership. He is responsible for the safety of the power plant and buying bunker and technical supplies in ports.

The engineer on watch must be usually present in the Engine Control Room and supervise the readings of all instruments, pressure gauges and devices. He must properly fulfill the orders from the bridge.

From time to time the engineer on duty must go to the engine room and inspect the machinery. If he detects some trouble such as vibration of any gearing or pump, high temperature of oil in the bearings, oil leakage from a pipeline, absence of cooling water in a tank and so on, he must do everything possible to prevent damage.

The Second Engineer is responsible for the main diesel engine or main turbine, reduction gears, propeller shaft and so on.

The Third Engineer is responsible for boilers, fuel oil tanks, compressors, separators and some other machinery. He is in charge of receiving bunker.

The Fourth engineer is responsible for all the deck mechanisms.

2. Ship Motorman’s Duties

The Motorman is responsible to the Second Engineer.

He is responsible for:

- Assisting the watch keepers in the Engine Room;

- Assisting with the maintenance of all machinery;

- General cleaning in the Engine Room;

- The adoption of safe working practices;

The Motorman on watch must:

- Check the fuel level in tank;

- Check the oil level;

- Refill lubrication oil tanks;

- Pump out the bilge of the Engine Room;

- Overhaul mechanisms;

- Take part in the emergency operations;

- Ensure bunkering and other oil operations;

- Measure oil and water consumption;

- Inspect and fasten the loose parts;

- Renew some part;

- Grease the machinery in the Engine Room;

- Do painting in the Engine Room;

- Repair something under the supervision an Engineer Officer.

3. Refrigerating Plants

Refrigeration is the process of eliminating heat. Refrigeration itself is based on one of the most important physical laws - the relationship between pressure and temperature.

Any refrigerating plant consists of four main parts: the compressor, the condenser, the regulator, the evaporator.

A compressor serves for compressing the refrigerant and delivering it to the condenser. The hot, high-pressure gas from the compressor is cooled in the condenser and condenses into a liquid. The condenser is usually cooled by water or air. A regulator is used for metering the liquid refrigerant in right proportion.

The evaporator is the first cooled by the refrigerant and then cools the surrounding air or other medium. After that the refrigerant returns to the compressor and the cycle of operation is repeated.

4. Steam Power Plants

Steam power plant is an arrangement that converts the energy of fuel into mechanical energy. Steam power plant consists of a boiler, a turbine, a condenser, a feed pump.

The feed pump supplies water to the boiler. The function of the boiler is formation of steam from feed water. There are two basic types of boilers in use in ships: the fire-tube boiler end the water-tube boiler.

Water-tube boilers have replaced fire-tube boilers for generating steam for main engines. There are two types of water-tube boilers - main boilers and auxiliary boilers. The main steam boilers generate steam for the main engines, driving the propellers, and for auxiliaries. The auxiliary boilers generate steam only for the auxiliaries and other ship's needs.

According to the pressure water-tube boilers are classed as low, intermediate and high pressure boilers.

A water-tube boiler consists of steam and water drums, water-heating tubes, a furnace, a super-heater, an air-heater, an economizer.

The furnace is used for combustion of fuel and generating hot gases. The hot combustion gases from the furnace pass upward and transfer their heat to the water in the tubes. Heat is absorbed by the water and steam is formed.

The function of the super-heater is formation of superheated steam from saturated steam. The economizer is used for heating feed water. The function of the air-heater is heating combustion air. The super-heater, the economizer end the air-heater are heat-transfer surfaces which cool the exhaust gases to the minimum possible temperature and increase the efficiency of the boiler.

Steam from the boiler passes to the turbine where the heat energy of steam is converted into mechanical energy. Steam from the turbine passes to the condenser where it is converted into water. The cycle is repeated.