Working Principle of Fresh Water Generator on Board Ship

Fresh water generator(FWG) is one of the essential machineries on board ship, After-all a large amount of fresh water is utilized on ship every day. On board ship Fresh water is used for the most part by huge boilers having steam turbines as main propulsion or cargo pumps driven by turbines. They all in all record for 30+ Tons of fresh water every day separated from the day by day necessities of 10+ ton for crew consumption as drinking, cooking, washing,Tank cleaning and different utilities. Adequate consumable water might be taken up against the cargo load capacity in the port for satisfying crew and machinery necessity yet isn't prescribed to utilize shore water for boilers because of their low quality, so Fresh water generator is unavoidable on board ship.

But why do we need the FWG on board in first place?

In the middle of good old days people used to bring across lots of water in their ship. It was good however it expands the load on the ship and furthermore water lack issues were always there. Be that as it may, the nature of shore water will be extremely (too much) bad to be used in water tube boiler and filling (expansion) tanks. The storage space that could have been used for fresh water can as a result be used for fuel or added/more space for payload and products (that are bought and sold) when fresh water generator is installed on a ship. As you may know the first (or most important) concern for running a ship or any transportation business is to make money. Further more Boiler needs demineralized water to reduce overall scale development and corrosion issues. It is also normally used to build the general efficiency of the running machinery, mostly it uses the engine warmth/heat by Cooling The Hot Jacket Cooling Water At Around 85 Deg Celsius To 65 Deg Celsius.

Working Principal Of FWG?

Extremely important rule of all low weight freshwater generator is that, boiling point of water can be decreased by lessening the pressure of the air surrounding it. By keeping up a low pressure, water can be bubbled at low temperatures say 55 degree Celsius. The source of warmth for the fresh water generator could be waste heat rejected by generators and main engine jacket cooling water. This decrease In Saturation Temp lead to early vaporisation of water due to vacuum created within the chamber. It Is Created By The Help Of An Air Ejector, Which Extracts The Air From That compartment/chamber. An Air Ejector Works On Bernoulli's Rule and being used side by side with a brine ejector used to suck salt water from the chamber. The vacuum help disappear the water leaving behind the salt or salt water to be sucked by salt water ejector. It is then passed through the dimmister (A sort of punctured plate with very minute gaps) which traps any water or salt particle traveling through it. The evaporated water is then condensed together with the help of ocean water and after that tested for sality with the help of salino-meter.

Regulations Regarding Production of sea water on board ship:

1. Ship must be 12 nautical miles away from the nearest coastline to start the FWG.
2. Engine must be running at full ahead sea speed during start of FWG.
3. Ensure main engine parameters are normal.
4. Ship is not in congested water.
5. Ship is not maneuvering.
6. There is no oil/chemical spill reported in the visinity of the ship.

Safety Equipments on A Typical FWG:

1. Vacuum Breaker For Releasing Vacuum when we shut down the FWG.

2. Relief Valve For Releasing The Excess Pressure.

3. High Salinity Alarm: It Is Fitted To The Salinometer As It Measures Higher Salt Content In The Water Produced.

4. Temperature Gauge.

Starting Procedures for Fresh water generator:

• First we need to ensure that suction, discharge and overboard valves for ejector pumps are under open condition. Now once been checked, start the ejector pump.
• Close the vacuum breaker valve.
• Make Sure the S.W pressure at ejector (air) is not less than 3 bar. Now wait for 10-15 minutes to build vacuum in the generation chamber of fresh water generator. Wait until it shows more than 90% vacuum.
• Now open the sea water feed to the evaporator. Check for the sea water level in the shell through the sight glass and ensure it is at optimum level controlling feed through feed valve. Once the heating coils are fully submerged by the sea water open the J.C.W valves to the evaporator slowly.
• Purge out any air in the system by opening air vent at the top of the evaporator.
• Check for evaporation from the sight glass and then start the salinometer.
• Divert the outlet back to the feed water until the salinity is under the limit.
• When the salinity level is as per the desired or set value, open the discharge valve of distillate pump which sends the water to the fresh water holding tank through flow meter.
• Increase the evaporation rate and start the discharge pump. Check for the sytem to be stable.

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Author Amit                                                          Article requested by: NIÑO GONZALES

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How to do crude oil washing on ships in 10 easy steps

COW or Crude Oil Washing cleans cargo tanks with jets of high pressure oil when the ship is unloaded. The crude oil is pumped through the washing machines to the jets and serves as a cleaning agent which is then pumped to land with the load/Product Discharge. It has been found that crude oil is more reliable washing medium than water. The washing / dissolving effect results in heavy, waxy and asphaltic deposits on the sides and bottom of the Holding tank to convert back into the liquid so that they are easily discharge To the shore. The Crude Oil Washing (COW) techniques has several advantages over washing with water, using Cow as the washing medium reduces the Sludge deposition, thereby reduces the discharge (Stripping) time and increasing the load/cargo flow. There low deposition of mud at the bottom of the tank which reduces Ship constant and so increase its dead weight. On the other hand washing with water takes more time due to more deposition of mud at the bottom. They not only cause delay in washing but also release hydrocarbon gases which becomes a challenge to gas free the tank. There are three essential prerequisites for the washing of petroleum product:

A fully functional inert gas system for maintaining the tank atmosphere in an inert state during the whole wash cycle.
Fixed Piping Lines for Tank washing system
Means to ensure that the bottom of the tank is clean and dry at the end of the operation.

The vessel must be equipped with an inert gas system which can function properly and produce Inert Gas with a maximum oxygen content of 5%. This should be maintained during the COW to ensure that the oxygen content does not exceed this value. No COW operation to be performed if the Inert Gas installation of the ship is not working properly and the oxygen content is not within the desired limit. The oxygen content must not exceed 8% by volume. The IG pressure in the tank must not be less than 200 mm. wg. The vessel to be washed with oil must be equipped with a fixed tank wash system connected by permanent lines to the main load venting system or by separate laundry lines of the loading system. The crude oil washing of discharging tanks takes place in a single step or in several stages during the discharge of the charge.

One Step Washing:

As soon as the tank is almost emptied , Washing starts and the tank is dried under pressure during the last washing step using stripping. The machine adjusts to the vertical angle from 0 to 140 degrees. Since single-stage washing is performed only during the last tank discharge stage, it is necessary to use the ship's instructor to remove the pump or reduce the speed of the charge pump so that the vacuum pump is effective. This method is generally useful between discharges at two terminals or between ignition operations.

Multi-stage washing

This involves washing the interior areas of the tank in stages as the load is pumped out of the tank. The revolutions of the charge pump are not reduced. Depending on the back pressure in the distributor of the vessel, this process results in a very small time loss during the bulk discharge of the tank. The wax and sediment collected in the spacers and other structural elements above the bottom of the tank are removed and pumped with the load to the ground. Any wax or sediment on the underside of the tank remains as long as the soil is not washed and stripped as a separate step. This increases the total discharge time, but is required for sludge control.


The machines are pre-set in the first stage at a vertical angle of 120 ° to 60 °. In the second step, when the loading level is about two thirds of the tank depth, it is set at a vertical angle of 70 ° to 30 ° and during the third stage when it is set to about 1 meter of the residual charge in the tank to 40 ° to 0 ° is. Each step is superimposed by approximately 10 ° in the preceding step, and the cycle is normally 11/2, ie, in the first step, for example, the nozzle moves in the horizontal plane by slowly changing its angle from top to bottom or from 120 * to 60 * from top to bottom, or from 60 * to 120 *, and from top to bottom, or from 120 * to 60 *

The regulation requires that the cow jets cover at least 90% of the horizontal surface area of the floors, rods and structural elements and at least 85% of the vertical direct zone. Shaded areas should be covered with splashes or deformations.

List of oil washing equipment controls
In the case of unloading of raw materials, the master must notify the competent authority and the terminal (or any other ship in transit to the ship), at least 24 hours in advance or at the time of compliance with the regulations. The washing of crude oil should only be approved once each step of the COW operation must be specified in the oil wash operation plan. There must be an operational checklist for the use of the crew at each port of discharge. This includes the control and calibration of all instruments to be used during the operation of the cow.

Pre-Arrival Checks at Discharge Ports

1. Notification to the terminal of the operation of the cow.
2. Is the oxygen analyzer successfully tested and operated?
3. Is the water heater and the flushing system of the motor compartment insulated?
4. All Valves Marked washing is isolated from that of engine room pipe line.
5. Are all V/vs closed for stationary tank washing machines?
6. Are the tanks cleaning lines under pressure and tested for leakage?
7. Do you make portable drives for the M/C quick tank sink that will be tested?
8. Have gauges on the top line relief manifold has to be verified.
9. Should the trimming system control equipment cheked?
10. Has the communication system been reviewed and tested?
11. Has the organizational plan been set up and defined the duties and responsibilities of crew?

 Checklist before cow Operation

1. All checks and conditions are in order prior to arrival.
2. Unloading/operating the raw oil wash has been discussed with ship and shore staff and is readily available the agreed plan for a simple reference?
3. Was the communication link between the control and control stations and the monitoring/shore station repaired and functioning properly?
5. Has the fixed and portable oxygen analyzer been verified and calibrated?
6. Is the inert gas generator functioning properly and the oxygen content of the inert gas is delivered below 5% of the volume?
7. Is the oxygen of the tank washed about below 8% in volume?
8. Is the gas pressure is positive for the entire cargo tank?
9. Keep person responsible for checking all the lines for leaks as soon as the operation starts?
10. Are stationary machines for the necessary washing and portable motor units, if installed, mounted and repaired?
11. Have valves and lines both in pump-room and deck been checked?

Checklist-During the operation of the cow

1. Is the quality of the inert gases supplied often controlled and recorded?
2. Are all deck and machine lines often tested for leaks?
3. Is the current tank only available for COW?
4. Is the pressure on the appropriate tank wash line indicated?
5. Is the processing time of the tank disk indicated?
6. Is the washing machine, which works with the propeller groups, often properly controlled and working?
7. is a responsible person constantly stationed on the bridge?
8. Will trim be satisfactory when bottom washing is in progress as specified in the COW manual?
9. Is the level in the reservoir for tank washing often checked to avoid overflow?
The cow should be abandoned immediately if:There is an error in the inert gas system or oxygen exceeds the permissible limit, or The pressure in the tank falls below the air pressure or a minimum required (usually 200 mm water gauge).

D Checklist-After cow operation

1. Are all the valves between the discharge and the washing line of the tank closed?
2. Has the laundry been drained of oil from the crude tank?
3. Are all valves closed to the washing machine?
4. Are the cargo pumps, tanks and pipes properly drained as indicated?

Sludge and sediment control

Under certain circumstances, substantial sludge may also form in the containers, even in the case of crude oils which are not normally associated with such accumulations. Studies of incidents of large sludge accumulation show that there are specific critical temperatures at which crude oil begins to precipitate hydrocarbon species that form mud. This temperature, cloud point, is the temperature at which the crude waxes change from their liquid phase to suspended, nearly solid particles with associated oil components. These particles separated by phases are installed at the bottom of the reservoir and form mud. Sludge from paraffinic crude oil, once formed, is extremely difficult to return to a liquid phase by heating alone. Even an effective COVER program, which eliminates them from boats, has only managed to solve the problem in shore-based containers.

Electrostatic risks
The oil used for COWing must be free of suspended water to minimize the formation of electrostatic charges by high pressure jets. To ensure that the oil supply to the VAE is dry, the cargo tank to be used must be discharged to the ground before the start of the COW. At least one meter of load must be discharged. This removes all bottoms from the tank before the mold starts. VACA procedures that remove the flushing fluid from the discharge current or use a sliding container that is then filled with clean oil will avoid this problem.

Image credit: Wikimedia

*Note: If anyone has any problem with the picture, please contact us we will act ASAP!

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Author ARPIT SINGH and Amit

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Air Compressor maintaince and Troubleshooting

In order for ships air compressors to work effectively, at any time, you should know what the most common problems can occur and their causes. You need to know how to take care of vents; How to hold and replace the air valves; Maintenance of pneumatic cylinders and pistons; And like the bearings adjust, crank pins and links. You should be able to replace and repair the lubrication , cooling, control and air systems.

AIR INTAKES

A clean, dry air is essential to the proper operation of the compressors. To do this, the air intake filters should be regularly inspected and cleaned; If the filter is clogged there is a loss of capacity. A clogged air screen or inlet filter can also lead to extraction of oil from a compressor crankcase, around the rings or through oil seals to cause an explosion. Remove the filter element and clean with a jet of hot water or steam or by immersing in a strong solution of sodium hydroxide. The filter housing must be drained and replaced. When the filters are soaked in oil, dipping in clean oil, intermediate and complete emptying must be done before the filter at the inlet changes. Do not clean the filter with petrol or kerosene! Vapors can accumulate and explode in the compressor or the receiver. Make sure that no rain or dew on the inlet side be present and a means to drain the water from suction tube be provided. The lines should be as short and direct as possible. To supply air compressor air to the divers, avoiding compressor absorbs every internal combustion engine exhaust. You should also avoid possible inlets fumes from the fuel tank, spilled oil or gasoline.

AIR VALVES

The inlet and exhaust must be clean and kept in good condition. The valves if have leakage are generally contaminated and cause a loss in capacity. Valves are removed by loosening the fastening screws or clamps and then removing the cover plates. Each relief valve , if provided, can be lifted. Each valve should be checked to ensure that it returns to the same port from which it was removed. The valves removed for inspection should not be removed for cleaning if the conditions so require. Usually, dirt or carbon in the valve hole can be removed without removing the valve. This is done by soaking the valves in kerosene, then giving a stiff, light brushing or light scraping. The action of the valve is to be tested by inserting a screwdriver through the seat opening; The valve must lift and close freely. If necessary, remove the valve, check the arrangement of the various parts so that the corresponding relationship is maintained with the valve assembly. (The periodic reports on board show damage to the piston and valve parts if connected poorly mounted valves in the way of the piston lugs protrude.) Before replacing the cylinder in a cylinder, replace the air valves, check the seals and replace them. Plates coated with copper or asbestos thin and thin copper. Alternatively, they can be used together of compressed asbestos temporary 1/16 inch. Each valve assembly is inserted into the same hole that has been removed. Since it may be difficult in many cases to distinguish between the suction valve and the pressure valve, care must be taken when the valves are inserted into the cylinder. Make sure the suction valves are open to the center of the cylinder and exhaust valves are clear. Failure to do so will result in serious injury or loss of capacity. Then, the valve cap in the cylinder ensures that the gasket is in place; Lower even coverage of nuts and again do not tilt the lid. Tighten the set screw of the valve or clamping screw, pulling the valve in its seat. If no special lock in the threads of the screw of the valve to prevent leakage leakage must be placed through a locking nut in a recess around the screw and placing welding or fuse wire.

CYLINDERS AND PISTONS

The cylinders on pistons should be inspected only AFTER the manufacturer’s technical manual has been consulted.   Be   careful   when   removing   heads,   particularly where metal-to-metal joints are involved, to prevent damage to the joint.

If replacement of piston rings is required because they are worn or broken, take accurate measurements of the cylinder liners. Standard size rings may be used in oversize cylinders if the oversize does not exceed 0.003inch per inch of cylinder diameter. The liner may also need to be replaced if it is badly worn or out of round. When replacing piston rings, first fit them to the cylinder to check for proper end clearance. You can file the ends, if necessary, to make them fit. The side clearance of the rings should be such that the rings will fall easily into the piston grooves, which should be deep enough for the ring thickness.  Ring splits should be staggered.  After you assemble the piston, wire the rings tight with a soft copper wire so that they will enter the bore easily. This wire can be removed through the valve ports after the ring has started into the cylinder bore.

When reassembling the air cylinders and heads, be sure  they  are  all  drawn  down  evenly,  especially on multistage   compressors   where   the   heads   contain cylinders  for  third  and  fourth  stages. Otherwise, the result will be excess wear on the cylinders and pistons.

When a compressor piston has been replaced, the piston end clearance must be checked. This is done by inserting a lead wire through a valve port or indicator connection. Jack the compressor over. When the piston has  moved  to  the  end  of  its  stroke,  the  lead  will  be flattened  to  the  exact  amount of  clearance.  The  wire should  be  long  enough  to  permit  a  reading  near  the center of the piston. These readings should be taken after any adjustment or replacement of the main, crank pin, wrist pin, or crosshead bearings. Methods of adjusting the clearances vary according to the compressor design. You should consult the manufacturer’s instructions for suggested   adjustment.

MISCELLANEOUS  ADJUSTMENTS 

From time to time other miscellaneous adjustments are  required  on  compressors,  including  those pertaining to  wrist  pins,  crosshead  shoes,  reduction  gears, couplings,   and   V-belt   drives.   The  manufacturer’s technical manual will give you specific information forth   care,   adjustment,   and  replacement   of   all   fitted bearings.  Refer  to  the  manufacturer’s  instructions  for detailed information  on  when  and  how  to  make  these adjustments.

Wrist pin bushings are replaced when necessary. This  is  done  when  they  are  worn  to  the  point of becoming noisy. In making a replacement, be sure the oil hole in the bushing is properly lined up with the oil hole in the connecting rod. After being pressed into the rod, the new bushing must be reamed.

Crosshead shoes are provided with shim or wedge adjustment.   Wear   should   be   slight,   but  adjustment should be made when the travel of the piston rod causes movement in the stuffing boxes.

Alignment of reduction gears and pinions should be checked periodically, especially on a new compressor. Misalignment  may  be  caused  later  by  settling,  straining, or  springing  of foundations; pipe  strains  on  turbine-driven compressors; bearing wear; or springing due to heat from a turbine.

Flexible couplings require very little maintenance when they are properly lined up.  Some types require occasional lubrication to prevent excessive wear of springs and bushings. A noisy coupling is an indication that the bushing is worn and requires replacement.

V-belt drives require adjustment for belt tension. Belts generally stretch slightly during the first few months of use. A loose belt will slip on the motor pulley and cause undue heating and wear on the belt. A tight belt will overload the bearings. Belts should be protected against oil and high temperatures.  To prevent rapid deterioration, belts should not be used at temperatures above 130°F. V-belts are usually installed in sets of two or three.  If a single belt is worn or deteriorated, the complete set should be replaced to ensure that each belt will carry its share of the load.

LUBRICATION SYSTEM

Proper care of a compressor lubrication system includes the following:-

1. Keep the oil at a normal level in the reservoir at all times to maintain proper oil temperature.
2. Change crankcase oil periodically, and at the same time clean and flush the crankcase and clean the oil filter.
3. Maintain proper lube-oil pressure by keeping the oil pump in good working order and adjusting the bypass relief valve.
4. Keep  the  oil  cooler  free  from  leaks  (since pressure  on  the  water  side  exceeds  that  of  the  oil)  to prevent oil contamination and emulsification.
5. Properly adjust the lubricator for the specified quantity of oil feed.

COOLING SYSTEM

Proper  care  of  a  compressor  cooling  system includes  the  following  inspections  and  maintenance procedures:

1. Periodically inspect the intercoolers and aftercoolers
2. Remove  collections  of  gummy  oils  or  tarry substances from the cooler tubes by washing tube nests with  a  suitable  solvent  and  drying  them  thoroughly before reassembling.
3. Correct any leakage in tube nests to prevent leaks of water into the compressor while secured or leaks of air into the water side during operation.
4. Inspect and clean the cylinder water jackets periodically with a cleaning nozzle.

When  filling  the  cooling  water  system  after  the compressor  has  been  drained,  open  the  water inlet slightly to allow the water to rise slowly in the cooler shells and water jackets. Vent valves fitted to the water spaces should be opened to permit entrapped air to escape and to remove any air pockets.

CONTROL DEVICES

Because of the great variety of regulating and unloading devices used on compressors, you will have to  consult   the   manufacturer’s   technical   manual   for information regarding the adjustment of these device son particular compressors.

If a control valve fails to work properly, it should be taken apart and cleaned Some valves are fitted with filter  filled  with  a  sponge  or  woolen  yarn  to  prevent particles of dust or grit from being carried into the valve chamber. These filters remove gummy deposits from the oil used in the compressor cylinders. When repacking, use only genuine wool. Cotton will pack and stop the airflow.  Relief   valves   are   very   important   for   safe compressor operation. They should be set as specified by the manufacturer and lift-tested by hand each time the compressor is placed in operation.  To check the setting periodically, test by raising the pressure in the spaces to which they are attached.

SUMMARY

Since an Engine man may encounter so many types of   compressed   air   systems,   air   dryers,   and  air compressors both ashore and aboard Navy vessels, this chapter presented only general procedures and facts.  To maintain, repair, and overhaul specific compressed air systems,  air  dryers, or reciprocating  air  compressors, you  must  refer  to  the  manufacturer’s  technical  manuals. A  definite  preventive   maintenance   schedule   with frequency and assignment of responsibility is required. You should have the manufacturer’s manual handy to establish   minimum   requirements  and   to   follow   its recommendations for maintenance.

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Author Amit                                                                            Article Requested By: Rauhjek

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Seawage treatment Plant on board ship | Explained

The discharge of untreated sewage in controlled or territorial waters is usually banned by legislation. International laws is in force to cover sewage discharges at certain distances from the earth. Accordingly, and to meet certain standards, all new ships have installed sewage treatment plants.

Two types of sewage treatment plants are used, using chemical or biological methods. The chemical process is essentially a reservoir that collects the solids for disposal in authorized zones or areas collection site. The biological process treats waste water, so it is acceptable to discharge near the coast.

Legal Regulations and  Ship’s  Sewage Discharge

Unloading the sewage and storage of sanitary water from ships and equipment and containers must be certified to meet the prescribed standards, it has been regulated according to national and international standards. The problem of marine pollution by ships is the International Convention for the Prevention of Pollution from Ships, 1973-1978 (MARPOL 73/78) introduced by the IMO.
MARPOL lays down rules and regulations that prevent downward marine pollution by using oil, chemicals, harmful substances in any form of packaging, waste water and waste, harmful gas emission and ballast.

The Convention comprises of a number of Annexes and Annex IV contains provisions regulating prevention and supervision of marine pollution by sewage waste waters from ships. Annex IV to the Convention refers to:
a) prohibiting or limiting discharge,
b) issuance of certificates and inspections,
c) equipment and supervision of discharge,
d) shore reception facilities.

MARPOL Annex IV, is applicable to ships on international voyages that are 400 gross tonnage and greater; or less than 400 gross tonnage when certified to carry more than 15 persons. The board discharge monitoring equipment should include at least one of the following sewage systems: 

• The sewage treatment plant will be managed by the administration taking into account the standards and testing procedures of the IMO.
• A grinding plant and waste water disinfection approved by the administration.
• Such a system will have for the temporary storage of sewage systems to the satisfaction of the administration, if the ship less than 3 miles from the next country.

Annex IV of MARPOL 73/78 (IMO) regulates the disposal of ships at international level. In addition, some countries have their own national and regional controls.

The board discharge monitoring equipment should include at least one of the following sewage systems:
The sewage treatment plant will be managed by the administration taking into account the standards and testing procedures of the IMO. A System liquidation and waste water disinfection approved by the administration. Such a system will have for the temporary storage of sewage systems to the satisfaction of the administration, if the ship less than 3 miles from the next country.

The Hazards and regulations regarding the Sewage Systems:

Water drainage and waste water narrow limits reduce the ability of self cleaning. You can see in the sediment to the water, along with hydrogen sulfide has a pungent smell. The combined hydrocarbon and carbon stimuli plant oxygen back into the water.

With less oxygen, the best aerobic bacteria or infections cause anaerobic bacteria to rise due to lack of oxygen and so requires a control. Together with the decomposition solution and the smell of decay and its process produce  gas (toxic). Consequently, the action of packing station a group of aerobic, is necessary for type of waste water.

Principle of Biological Treatment Plant

The system require slow and steady fluid flow. The accumulation of heavy slime is a problem even , longer stay in the aeration chamber significantly reduces the cost. For example, 80% of the waste water contains solid reduced waste after 12 hours of aeration tanks in 20% of its original weight.

The aerobic process to remove dissolved oxygen in water generates water, carbon dioxide and bacteria.

Operation of Biological Treatment Plant

Image Source : http://www.marineengineering.org.uk (Used For reference purpose only)

The above plant shown has 3 chambers. The sewage enters the aeration chamber through a coarse filter where large solids decomposes, Then it goes to the ventilation chamber  where the main biological effect takes place. Here air blower mounted on the sides of the unit used to pump in air for the survival of aerobic bacteria, product flow of oxygen and bacteria was stirred through a series of pipes and nozzles. Then the waste is in the aeration pool for a sometime.

Move sewage from settling basin (or funnel) into the biological flocculate under resting conditions, aeration enters and bacteria settles and to the aeration chamber by pumping air by using blowers. A second transfer line is from the surface of the settling basin and extends to the aeration chamber. This transfer mud which contains bacteria that the waste water enters to digest.

Safety Parameters:

Anaerobic bacteria in all forms in a given situation, give away toxic and flammable gases. There is a need to participate in reducing the required anaerobic in treatment plant. You can carry the gas freeing so it can not enter the damage limit.

Here are some ways you can help reduce the risk:
Use air bathroom to reduce the risk. There must be a positive pressure in the chamber at all time to avoid any further gassing and risk of aerobic bacteria to die out. When the water storage tank is flushed out, maintain a system of oxygen in the water. For example, it can be entrained in the water so can be injected directly into the air, or air is pumped in. You should check the container. If you use aerobic treatment device, always check that the direction of operation of the plant should be considered positive. You should refer maintenance system whenever needed.

Maintenance of Aerobic treatment units

1. Check for regular cleaning and care being paid to areas behind internal division plates
2. Checks on alarms and trips
3. Checks on aeration equipment
4. Checks on transfer systems in the tanks
5. The chlorination of the sample should be between 1-5 ppm

# Various books, study material and other online sources has been refereed prior to writing this article but no part is copied or produced  from any of the source but explained same thing in better detailed way.

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Author Amit                                                                            

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Watch Keeping at sea for Marine Engineers | Step-by-step

Watch keeping is an integral part of marine engineer’s duties on board ship. The technicians perform tasks and routines for monitoring the ship's engine room. The clocks are divided into three periods of four hours and the following work must be carried out and checks carried out at sea.

• Check the colour of  exhaust emission from funnel.
• Check the Economizer temperatures, pressure drop and the system for any leakage.
• Check the oil fired boiler water level, blow through gauge glass and check pressure.
• Check the boiler circulating pump for operating pressure, vibration, noise, gland leakage and bearing oil level.
• Check and confirm normal operation of incinerator if running.
• Check the waste oil tank level and temperature, drain off water.
• Check Main & Aux. engine header tank levels, if they require filling record the quantity of water added.
• Check the temperatures and pressure of the fuel valve cooling system. Examine the level of the F. V. C  header tank, check for contamination and confirm through flow.
• Check stern tube header tank level, return flow, sump, pump and oil condition.Examine M. E cylinder tops for leakage, movement, overheating and any temperature or pressure outside the normal parameters.
• Check for exhaust gas leaks.Examine turbo charger oil levels, pump operation, temperatures, pressures and differentials, whilst checking also for any unusual noise or vibration.
• Monitor air cooler pressure drop, and ensure Makers operating parameters are adhered to with regard to dew point temperature.
• Check cylinder oil day tank level and individual lubricators for level, flow and function.
• Check all bunker fuel tanks for level, temperature and drain for water.
• Check fuel fine filter differential.Examine fuel pumps for leakage or unusual noises.Ensure oil mist detector is functioning correctly and test alarm.
• Check ME governor oil level and fuel pump racks.
• Examine auxiliary blower if running and scavenge belt to ensure that scavenge and air cooler drains are clear.
• Feel over scavenge belt.Test air line drains for water.
• Check all standby pumps are on auto mode and ready to start.
• Check air compressor  oil level, and the temperatures and pressures whilst  running.
• Check fresh water generator for normal operation & also chemical dosing to feed line.
• Check sewage treatment plant for normal operation.
• Examine A/E and check all running parameters are within limits. Fuel leakage, non fitting of double skin pipes and removed  protection or insulation from exhaust manifolds to be rectified immediately .
• Check A/E bilge’s for leakage.
• Confirm that an alternator engine is on standby in the control room and that the L. O priming pumps are on Auto.
• Checking drinking and domestic water hydrophore systems for levels, and leakage. Ensure that the Calorifier, circulating pump and UV Sterilizer are operating satisfactorily.
• Examine boiler feed water system for normal pump operation and check the cascade tank for temperature and level. Also check that there is no hot well contamination with fuel oil due fuel oil heating coil leaks.
• Examine air reservoirs and check the drains for water, ensure that control and service air reducing valves are functioning correctly and that the control air dehydrator is operating normally.
• Examine the purifier room for leakage, ensure that running purifiers and operating normally with regard to oil levels, flow rates, temperatures and pressures. 
• Ensure lowest throughput for L O purifiers.Check Calorifier.
• Examine Booster pumps, flow-meter and heaters for normal operation without leakage.
• Ensure that all main engine pumps are running normally and that standby pumps are ready for Auto operation.
• Check HFO Serv & Sett tanks levels and temp. Drain off water.
• Check all running purifiers for normal operation. Check gear case oil level, Separated Oil temperature and feed rate, motor load etc.
• Skim off sludge from recycle tank.
• Check F. O booster p/p, check F. O temperature.
• Check JCW pump and motor for normal operation.
• Check M/E Lubricating Oil Pressure (Bearing), X-Head Oil Pressure and Piston Cooling.Check piston cooler and L. O cooler in/out temp.
• Check sounding of all sludge tanks, bilge storage tanks, compare with previous sounding.
• Check M/E L O pump discharge filter Pressure drop.
• Check M/E L O pump/motor for normal operation.
• Check thrust bearing L. O temperature Fwd/Aft.
• Check E/R bilge level with special attention under the flywheel.
• Check L. O levels and temps of intermediate shaft bearings.
• Check stern tube L. O sump level, oil pressure, temp and return flow.
• Check M/E L. O sump sounding. compare with earlier soundings recorded.
• Check and confirm L. O purifier is operating normally note L. O temperature.
• Check piston cool leak off tank, open skimming v/v to skim off oil from top.
• Check piston cooling water tank level top up if required.
• Check and confirm main S. W p/p, motor and auxiliary  S. W pump/motor working normally.
• Check piston cooling p/p pressure and in/out temp of all units check flow.
• Check A/E load and winding temp. Do a function test on alarm panel. Reconfirm all running parameters of M/E and A/E.
• See the Chief Engineer’s standing instruction book and also notice board for daily instruction and guidance. Discuss with outgoing watch keeping engineer if there have been any special operations problems during his watch or any change in status of running machinery Function and lamp test of Alarm panel.
• Check no alarms are inhibited.Ensure no alarms indicating abnormal condition are active.
• Ensure air and water on deck shut if not required.
• Log down all parameters in log book
• Check for following hazards and rectify :-
• No Fuel, L. O or water  leaks.
• No loosely stowed equipment.
• Gas bottles shut and welding plant shut down.
• Fuel high pressure pipes for M/E & A /E’s secure and no leaks.
• No abnormal vibrations of any type.
• No water tight openings open unnecessary.
• Ensure that the welding equipment is off.Double check additional A/E on standby, and Emergency Generator on Auto.
• Double check M. E controls on Bridge and max speed limit set as per Chief Engineer’s instructions
• Check no alarms have been isolated, unless authorized by C/E and E/O. Note there are no existing alarm condition, unless a valid reason and C/E and E/O aware of.

WHEN IN DOUBT DO NOT HESITATE TO CALL CHIEF ENGINEER

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Author Amit                                                                            

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How to prevent oil spillages and leakages during bunkering operation

Oil spills and leaks in fuel operations are an important source of contamination from discharges from ships. Experience has shown that most of the bunkers spill and overflow, which can be attributed to human error.

It is important that all operations are carefully planned and fuel runs. It is to be noted that due to the heavy oil spill pollution is particularly harmful and difficult to clean.

The personnel involved in the bunkers on board does not have to have other tasks and must remain at their jobs during the filling process. This is particularly important when the simultaneous loading with loading cargo, should avoid conflicts of interest between the operating staff.

Safe storage procedures:

Ship operators should require that all fuel operations are controlled in a process that is part of the ship safety management systems. The procedure must ensure that it is linked to the risks associated with the operation and controls in place to mitigate these risks. The procedure should also take into account emergency measures for loss containment. The operator should take into account when developing the process:

1. Determine that there is enough space for the volume of loaded cargo spaces.
2.Controls for the system valves hold.
3. Determination of the load factor for the beginning of the load, mass and auction sold.
4.Arrangements of bunker tank ventilation.
5.Tank overflow internal arrangements.
6.Setting alarm override alarm units.
7. Communicate with the terminal to determine when you are making fuel.
8. Communication Provider Bunker before the loading process to establish and start recording and how the quantity and quality controls can be carried out, especially if secure access between the ship and a barge is required.
9. Bunker management practices have dealings or may have a H2S salary.
10.Testing procedure to determine the presence of hydrocarbons or H2S vapor.
11.Method Determination temperature Bunker during charging.
12. A communication procedure for operation, including the emergency stop.
13.Monitoring of the bunkering operation and checking it conforms to the agreed procedure
14.Changing to tanks during charging.
15. Establish a maximum load volume for all reservoirs.
16. Special precautions for loading in double-bottomed tanks.
17. Having made arrangements for retention and cleaning equipment.
18. Requirement management to ensure safe operation.

After the intervention, a checklist must be implemented.

Responsibility of personnel engaged in bunkering operation:

The staff on board who is appointed to manage the operation of the fuel should not be involved in other operations. Spills are often caused by the staff distracted from another task. Before the start of the operation carried out all the controls and preload checked communication systems the work. The loading rate should be checked regularly.

Care should be taken when switching from tank to tank to ensure that excessive pressure is not applied to the rows of pipes or load. When filling tanks, it reduces the loading speed, reduce the possibility of air pockets in the container to the mist caused by the ventilation openings is transported and to minimize the risk that the supplier is enough to not stop quickly.

At the end of loading, all pipes and hoses should be drained before being separated into the tank or, if necessary, back to the barge. The practice of air ducts in the fuel tanks blows is common but a high risk of causing a spill when the tank is full and has only enough space to end the load.

To the responsibility for the security of the operations, while a ship bunker reception barge is shared the captains of the tanker and barge jointly. Fuel exploitation of responsibility is usually delegated to certain officials responsible for the boat and the barge. Before the bunking commissioning, the responsible should:

•Agree in writing on the handling procedures including the maximum transfer rates.
•Agree in writing on the action to be taken in the event of an emergency during transfer operations.
•Complete and sign the Bunkering Safety Check List.

Safety Manual List Bunkers Tax

The checklist uses security bugs to assign responsibility and accountability. Acceptance is confirmed by ticking or part of the box and finally signing the declaration. Once signed, the minimum basis for safe operation agreed by the mutual exchange of critical information is described in detail. Certain statements in the checklist are considerations that the ship is solely in charge of and responsibility, some of which the barge's sole responsibility and liability and other attribute responsibility and shared responsibility. The gray grades are used to identify statements that are not universally applicable to a party, even if the ship or the barge can create such sections if they so wish.

The division of responsibility and accountability does not mean that the other party's behavioral examinations exclude compliance. The division of responsibility and accountability allows a clear identification of the party responsible for the first compliance and continuing education throughout the transfer activity.

The responsible persons completing the checklist should be the people carrying out the bunkering operation.

The tankers representative should personally check all considerations lying within the responsibility of the tanker. Likewise, all considerations that are the responsibility of the boats must be personally monitored by the representative of the barge. In their responsibility, representatives must ensure that the security standards on both sides of the transaction are acceptable. This can be achieved by means such as:
i) Confirming that a competent person has satisfactorily completed the checklist.
ii) Sighting appropriate records.
iii) By joint inspection, where deemed appropriate.

Before the start of operations, and sometimes for mutual safety, member barge of the staff and, if necessary, a responsible official will perform inspections of the barge and carry out the vessel to ensure that his obligations, list, they are treated effectively.

The safety cabin list contains the following sections:

1. Bunkers to be transferred

A joint agreement on the amount and degree of the bunker transferred and the agreed transfer rate and the maximum return pressure.

2. The fee for the loading tanks

Identification of bear tanks sufficient space to ensure it is safe to transfer the bunker. A space for receiving the maximum filling volumes of each container and the volume provided.

3. Control barge before going to berthing

This section will be checked before the ship is next to the ship.

4. Checks before transfer

This section will perform controls to be presented jointly before the transfer activities.

Safety checks prior to berthing

1. The barge has obtained the necessary permits to go to the receiving container.

2. Mudguards have been checked, are in good condition and there is no way to metal against metal contact.

3. When fairly reasonable electrical insulation compound be present on the barge / boat.

4. All keep hoses in good condition and are suitable for the desired service.

5. The Ship is safely anchored.

6. It is a safe means of access between the ship and the barge

7. Effective communication has been placed in the place between the officials. (VHF / UHF .......... Ch)
Primary System: Backup system: emergency stop signal .

8. It is an effective clock on the barge and ship storage bunkers.

9. Firefighting hoses and fire extinguishers against fire on board the barge and the vessel are ready for immediate use.

10. All culverts are blocked. Detachable connectors at all times. The drip cups are in position around  the fuel tank vent openings.

11. Bunker connections are empty and completely screwed.

12.The transfer hose is properly rigged and fully bolted and secured to manifolds on ship and barge.

13. The valve housing is connected to the charging system, the holder of the engine compartment and bunker lines is closed and sealed.

14.All cargo and bunker tank hatch lids are closed.

15. The content of the bunk tank is not monitored at intervals. Supply oil spill clean

16.There is a supply of oil spill clean up material readily available for immediate use.

17. Radars are switched off.

18. The radio is in low power.

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Author Amit                                                                                      Article Requested By: David

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Arrival and departure checklist for engineers on Ship (Engine department).

The preparations for loading, unloading and a sea voyage requires a long list of tasks in form of checklist before the ship arrives or depart. Each ship has a checklist that is used by the service technician to prepare the engine for arrival and departure. Usually you will receive a message before 1 hour to final departure or arrival. The service technician will be called just before the hour of maneuvering.

Arrival Checklist

UPON RECEIVING ONE HOUR NOTICE FROM BRIDGE

• Inform chief engineer.
• Start standby generator and take on load.
• Stop fresh water generator as and when bridge starts reducing rpm to 95.
• Start main engine auxiliary blowers.
• Main air compressor put in auto, bottle pressed up and condensate drained.
• Auxiliary oil fired boiler on standby mode.
• When engine stopped check for speed log less than or equal to 7 knots try out main engine ahead/astern direction.
• Test telegraph, steering and clock synchronized.
• At STBY (EOP) note down counters and flow meters.
• Change over from low to high sea chest.

UPON RECEIVING FINISHED WITH ENGINE (FWE)

• Open indicator cock and blow through engine by air.
• Engage turning gear and turn the engine with manually pressing of cylinder lubricator.
• Stop main engine auxiliary blower.
• Block main start air valve on the main engine.
• Close main air starting valve on the air bottle.
• Open turbocharger drain and cover the turbocharger blower suction filter.

Departure Checklist
UPON RECEIVING ONE HOUR NOTICE FROM BRIDGE

• Inform chief engineer.
• Start standby generator and take on load.
• Check for main engine (M/E) lube oil pump, camshaft lube oil pump, main engine circulating and supply fuel oil pump running and pressure are normal.
• Engage turning gear and turn the engine with manually pressing of cylinder lubricator. Once complete disengage turning gear.
• Start boiler water circulating pump.
• Main air compressor put in auto, bottle pressed up and condensate drained.
• Test telegraph, steering and clock synchronized.
• Open main start air valve on the main engine.
• Open main air starting valve on the air bottle.
• Close indicator cock, turbocharger drain and remove the cover for turbocharger blower suction filter.
• Ensure all moorings are tight, gangway lifted and propeller clear prior blow through engine.
• Start main engine auxiliary blowers.
• Give control to bridge, try out engine ahead/astern direction.
• At STBY main engine note down time, counter and flowmeters.

UPON RECEIVING RFA (COP)

• Note down time ,counter and flow meters
• Prior starting freshwater generator ejector pump confirm the condition of sea water from bridge.
• Close main engine jacket water preheat steam slowly and maintain jacket water temp 80-85 deg centigrade.
• Put the main engine auxiliary blower control in auto.
• Maintain all parameters at normal working condition.

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Author Amit                                                                                      Article Requested By: Akul Gupta

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