Guide Ship's Systems and Controls

Numerous different ships systems and controls being maintained by engineer officers are used on all types of vessels today. These consist of engine room systems such as lube oil, fuel oil, and seawater, along with deck officer's roles such as cargo recording and navigation.

Management of the Various Systems Within the Engine Room and Deck Departments

A ship could not function without management of the systems incorporated within her hull and deck. The following sections provide articles on this subject, and I have put these in their relative groups with a brief description. The subjects have been divided under general headings and linked to articles written by myself and other Bright Hub writers in the Marine Engineering channel. We begin with the various systems and controls within the engine room, before moving onto examples in the deck department.

Ships Electrical Systems

The electrical power is supplied from the generators to the main switchboard from where it is distributed to all parts of the ship through numerous breakers and relays. It is maintained by the Electrical / Electronics Engineer. There are normally three generators, one running and supplying power, one on standby, and one down for maintenance whilst at sea. When maneuvering or alongside working cargo, two generators share the load with the other on standby.

• Marine Electrical Power Distribution
• Ship to Shore Supplies
• Electrical Grounding on Ships.
• Electrical Power Generator Protection

Lube Oil Systems

The lube oil system comprises of the main engine sump, suction and discharge filters, circulating pump, coolers and centrifuge. The sump is the main storage tank, located under a grill in the crankcase. The suction and discharge filters remove any particles contained in the oil. (Any pieces of white metal in these could indicate bearing wiping, and must be investigated)

The cooler is required to maintain optimum temperature and viscosity and cools the oil using seawater that passes through tubes or plates depending on the type of cooler.

Regular centrifuging of the oil is essential for removing particles and water from the oil sump; some engines have the centrifuge running twenty-four hours a day; only being stopped for cleaning.

• Effects of not maintaining Lube oil system.
• Crankcase Lube Oil System
• Lube Oil Used in Marine Diesel Engines
• Lube Oil Cleaning by Centrifuging
• Use of Lubricants Aboard Ship
• Marine Oil Piston Cooling Using Lube Oil
• Treatment of Marine Engine Lube & Fuel Oil
• When Should Lube Oil be Changed
• Operation of Marine Lube Oil System
• Problems in the Lube Oil System
• Boundary and Fluid Film Lube Oil Systems
• Cylinder Liner Lube Oil System
• Wet & Dry Lube Oil Sumps
• Types of Lube Oil Systems

Heavy Fuel Oil System

The majority of ships engines use heavy fuel oil (HFO) being a by-product of crude oil refining. It is taken on board ships as bunkers, a sample of which should be checked by the Chief Engineer, as some suppliers abroad have been suspected of mixing old sump oil and even scavenge drains with bunker oil.

Before use in the main engine the HFO must be processed by heating, filtration, purifying, and clarifying. The heating is to keep the oil from waxing and improve the usually high viscosity; filtration is carried out at various stages of the process to remove particles. Purifying removes the water and sludge in the HFO, and clarification removes the solids.

• Preparation of Heavy Fuel Oil
• Handling, Storage and Use of Heavy Fuel Oil
• Marine Heavy Fuel Oil Contaminants
• HFO from Crude Oil Refining
• Taking on HFO Bunkers
• Marine HFO Management System
• Treatment of Marine Engine Fuel & Lube Oil
• Centrifuging Heavy Fuel Oil

Ship’s Deck Systems and Control

The Deck Officers use various methods to control the various systems of navigating, tank cleaning, steering the ship, or control of the cargo. Control of the cargo and producing a cargo plan is also the duty of the Deck Officers, usually the mate or Second Officer. It is a very important document required to keep a record of the type, description, and weights of the various pieces of cargo stored in the holds or on deck. It also notes its location as well as the sequence of loading, and thus the reverse order of discharge, in the various ports of call.

Ship’s Cargo Plan

Navigation System

The bridge is the Deck Officers domain. When I was at sea as an engineer, I used to go up to the bridge when off watch and marveled at the sophisticated navigation gear even in those far off days of 40-odd years ago.

This consisted of the auto-pilot, gyro-counter, radar screen, ship's speed and distance run, all neatly arranged on the bridge. The links below provide further information on this subject.

• Use of Marine Navigation Lights
• Marine Navigation Terminology
• Rules for Ship’s Navigation
• Use of the Magnetic Compass in Navigation
• Electronic Navigation Chart Explained
• Tour of a Ship’s Bridge
• Marine Navigation Using GPS
• Tools used in Celestial Navigation

Cargo Tank Cleaning Systems on Oil Tankers

When I was an engineer at sea, I used to dread the tank cleaning as the whole ship smelt like a petrol station forecourt! However it must be done in preparation for the next cargo. Gas freeing of the tanks is carried out first, with this being a combination of inert gas flooding and venting of the tanks.

Gas freeing and tank cleaning is under the remit of the Deck Officers; the Chief Officer normally being in charge of operations.

Tank cleaning occurs after discharge of cargo and gas-freeing, usually while on the sea voyage to the next loading port. The following two links explain the process involved in these systems.

• Gas Freeing and Tank Cleaning on Oil Tankers
• Inspection of Cargo Tanks on Oil Tankers

Ships Ballasting Systems

This is under the control of the Deck Officers using their own pumps in the pump-room or requesting the use of the engine room seawater on deck pump. Ballasting is carried out as the cargo is loaded or discharged to maintain the ships stability. There has been a lot of controversy lately regarding taking ballast on in one port and discharging in another port. This can transport and transfer alien species that will wreak havoc with the local flora and fauna.

• What is Ballast Water
• Problems Encountered in Discharging Ballast Water
• Ballast Water Management

References

Brighthub: Ships Control Systems

Maintenance Schedule for Marine Auxilliary Diesel Engines

Marine Auxiliary Diesel Engines are used for the generation of electricity on board merchant ships worldwide. This article discusses the various running hours based maintenance like 250 hours routines, 1000 hours, 8000 hours routines, as well as the daily checks to be made by a marine engineer.

Maintenance of Marine Diesel Engines

A marine diesel engine has to be maintained in conformity with the various international rules and regulations as per the ISM code. The advice of the manufacturer, as well that of the class and the Administration has to be followed. Thus all marine diesel engines have a maintenance schedule which is normally integrated into the preventive planned maintenance program of the company. It is kept on a dedicated computer with specialized software, which when fed the daily running hours gives you the work to be done, the work becoming due, and the work which is overdue. The ship’s data is synchronized with the head office data by the ways of data exporting twice a month. This allows a superintendent engineer to monitor the ship from the shore office and instruct the chief engineer accordingly. A maintenance schedule has been discussed in this article to give a rough guide line to the marine engineers. However the specific maintenance schedule given by the manufacturer should be followed and the local conditions, the load on the engines, would make it necessary to have a shorter maintenance interval. Engines running on light loads would require more frequent cleaning of the exhaust spaces and the pistons due to higher likelihood of fouling. In addition to the above, any unusual operating conditions, increase in sound, exhaust temperature, etc. must be investigated promptly and corrective actions taken.

DAILY CHECKS ON THE ENGINE

The following are the daily checks on the engines that should be made by all the watch keeping engineers in their duty hours.

1. Check the fuel level in the service tank and drain the service and settling tank of any water.
2. Check the lube oil level in the sump of the engine.
3. Check the governor lube oil levels.
4. Check the lubrication of the rocker arms (if running)
5. Check lube oil pressure, water pressure, exhaust temperatures, cooling water temperature, lube oil inlet temperature, etc. (if running).
6. Drain the condensate from the scavenge manifold and the air coolers.
7. Lubricate the fuel racks, linkages, and fuel pump rack operating gear.

250 HOURS ROUTINE

After an engine has run for 250 hours the generators must be changed over and the engine stopped and the following must be cleaned.

1. Clean the lube oil filters.
2. Clean the fuel oil filters.
3. Clean turbocharger air filters.

1000 HOURS ROUTINE

A thousand hours routine is little more exhaustive, and we have to check that the injection system and the running gears are all OK and nothing is amiss. The following is done by marine engineers at a thousand running hours of the engines.

1. Crankcase inspection to be done.
2. Remove the fuel injectors and pressure tests them. Adjust the pressure and put back.
3. Change the turbocharger blower and turbine side oil.
4. Check the tappet clearances.
5. Take the performance of the engine.

2000 HOURS ROUTINE

The crankshaft alignment must be checked and the graph plotted. It must be cross checked with the original figures. Once the diesel engines have been set up on the ship, it is very important that the engines be maintained within limits of the initial alignment to obtain a satisfactory performance of the engine and the alternator bearings. Though during the construction phase of the ship a very stiff seating is provided to the engines as foundation, the ship will either hog or sag during the operational life of the ship due to loading and discharging cycles. It is the duty of the operational engineers to take crank shaft deflection at regular intervals and monitor the alignment of the engines.

4000 HOURS ROUTINE

The four thousand routines are very important and is known as half decarbonization. Basically all the cylinder heads have to be reconditioned and the carbon removed. The liner and the piston top are inspected for any abnormal combustion tell tales. In addition the following are done.

1. All cylinder heads to be removed, overhauled and carbon removed.
2. The exhaust and inlet valves inspected, lapped, and tested.
3. The starting air valves overhauled.
4. All gaskets, o rings to be renewed.
5. The cooling water spaces of the cylinder heads to be cleaned.
6. The top of the piston and the cylinder liner top part cleaned.
7. Renew the lube oil if required as per the analysis reports.

8000 HOURS ROUTINES

The 8000 hours routine is called decarbonization by marine engineers. During this all the pistons are pulled out, cleaned, and inspected. The piston rings changed depending on the wear down, the shell bearings inspected, and also the cylinder heads overhauled. In addition the following is also done.

1. Remove cylinder heads and overhaul.
2. Withdraw pistons and clean. Change piston rings.
3. Clean exhaust piping and silencer.
4. Inspect big end bearings.
5. Overhaul turbocharger and renew the ball bearings.

25000 HOURS ROUTINE

Renew the connecting rod bolts.

CONCLUSION

The marine auxiliary diesel engines are used for generation of electricity, and hence must be maintained in good condition. The marine engineer has to be on his toes taking care of the engines. The above is just a guide line, but the management in consultation with the engine manufacturers may change the schedule of maintenance. Today’s new engines have a running period of 16,000 hours before taking out the piston. However the old ships still follow the 8000 hours routine. Sometimes the management company likes to over maintain the engine so that it reduces the interval between the overhauls.