An Introduction to gas turbine

In the name of ALLAH who is the most beneficient and merciful

The aim is to be able to identify and explain the function of gas turbine major engine component and discuss the mode of operation of simple and complex cycle gas turbine engines compared with diesel and steam plant.

Definition of a Gas Turine

A continuous cycle self contained heat engine using a gas as the working fluid.

Breakdown of definition

1.      Energy output. After providing the power to drive the compressor(self contained) the energy output may be in the form of :

·         Jet thrust

·         Shaft power

·         Compressed air from compressor

·         Heat

2.      Self contained. Once running it is not dependent on any other machine.

3.      Gas may be.

·         Air – Open cycle

·         Hydrogen, helium etc closed cycle . In this case heat is added by means of a heat exchanger.

4.      Energy source. This may be provided by

·         Oil fuel

·         Natural gas

·         Sewage gas

·         Waste gas

·         Waste heat (eg blast furnance)etc .

5.      Compressor. This is usually either axial or centrifugal, but free piston and reciprocating compressor have been tried, although the process then is no longer continuous.

6.      Continuous. Unlike a diesel which operates with gas in a similar way the GT uses a constant pressure process which is continuous.

Comparison of cycles

In the services we are concerned with three main forms of providing power (see below). These all have particular advantages and disadvantages, some of which can be readily appreciated by a quick comparision of the ideal cycle on a T-S chart.

The following factors show themselves:

1)      Steam Plant

• Operates across saturation envelope.
• Closed cycle – recovery process needed to condense and re-use steam, hence much additional machinery.
• Small work to compress fluid. Good work from expanding vapour- large exess.

2)      Diesel

·         Fairly good available work output after compressing gas.

·         Open cycle.

·         Non-continuous cycle means valves and moving parts. Stress problems.

3)      Gas turbines

• Very poor specific work output available after compressing gas. High powers only available if:
• Component efficiencies high
• High mass flow
• High mass flow possible because process is continuous.

Conclusions

From the above comparisons the factors which stand out about gas turbines are:

• Unlike The others, an overall power output is possible purely because the constant pressure lines diverge with increase in entropy.
• Its specific output is very small and dependent upon the efficient operation of the various components. Mass flows are high hence small increases in component efficiencies will give relatively large increases in output.

Refrigerant

R12 CCL2F2 FREON 12

R22 CHCLF2 FREON 22
R502 CHCLF2 / CCLF2CF3

FOR FREON 12
Actual refrigeration effect = 400 kj/m3
compression heat= 66kj/kg

FREON 11 (VERY LOW PRESSUREFRERIGERANT ; suitable for large air conditioning installations)

FREON 22 (suitable for low temperatures without negative evaporator pressure in vaccum)

FREON 502 (for hermetic i-e integral gas tight motor and compressor)

THERE IS NO IDEAL CHOICE IN THE FREON GROUP AS THERE ARE ADVANTAGES AND DISADVANTAGES FOR R11 ( CC;3F)

FOR GOOD HEAT ENERGY TRANSFER RATE AT A TEMPERATURE DIFERRENTIAL OF ABOUT 8DEGREES BETWEEN COOLING WATER INLET AND CONS\DENSATION TEMPERATURE IS USUAL.

WRITTEN BY S/C ZEESHAN AHMED (A/C 2988)

INSTRUCTOR: CHIEF ENGINEER TAHIR JAMIL

DATE: 25/10/2009

TIME: 10:05:00 AM

Fuel consumption and efficiency

 In merchant ships the optimum design, maximum thermal efficiency and minimum fuel consumtion are arranged for full power condition. Specific consumtion is much higher when speed are at maximum. In IC engines such as diesel generators has peak thermal efficiency at 70% of maximum load. When all units developing equal powers. The power estimation method provides fuel consumption values. The rate of fuel consumption is the amount of fuel used in a unit time eg. Tonne/day.

Since fuel consumption @ power

Where   power= tone2/3 x V3

                        _____________

                        Admiralty coefficient

Then fuel consumtion/day=_displ2/3 x v3_______________

                                                Fuel coefficient

How would you become aware of a scavenge fire? How would you deal with a scavenge fire?

The first indication of a scavenge fire may be a slight reduction in the engine speed due to the reduction in power which comes about when a fire starts. Other indications are a higher exhaust temperature at the cylinders where the scavenge fire has started and irregular speed of turbo-blowers. External indications will be given by a smoky exhaust and the discharge of sooty smuts or carbon particles. If  the scavenge trunk is oily the fire may spread back from the space around or adjacent to the cylinders where fire started and will show itself as very hot spots on areas of the scavenge trunk surfaces. In ships where the engine room is periodically unmanned, temperature sensors are fitted at critical points within the scavenge spaces. On uniflow-scavenged engines the sensors are fitted round the cylinder liner just above the scavenge ports. A temperature higher than reference or normal then activates the alarm system.

If a scavenge fire starts, two immediate objectives arise; they are to contain the fire within the scavenge space of the engine and to prevent or minimize damage to the engine. The engine must be put to dead slow ahead and the fuel must be taken off the cylinders affected by fire (see note). The lubrication to these cylinders must be increased to prevent seizure and all scavenge drains must be shut to prevent the discharge of sparks and burning oil from the drains into engine rooms. In allows the fire to burn itself out without damage. Once the fire is out and navigational circumstances allow it, the engine should be stopped and the whole of the scavenging port examined and any oil residues found round other cylinders removed. The actual cause of initiation of the fire should be investigated. If the scavenging fire is more major nature. It sometimes become necessary to stop the engine and use the steam or extinguishing arrangement fitted to the scavenging trunk. The fire is then extinguished before it can be spread to surfaces of the scavenging trunk. Where it may cause the paint to start burning if special non-flammable paint has not been used.

Marine gas turbine (GT)

In the name of Allah (The most supreme knowledge)

An aircraft can use the energy in the gas stream directly to provide the propulsive power eg in a jet. In the marine environment this is not feasible because of the very nature of the surroundings , the noise, the requirement to reverse and limitations imposed by the construction of the ship. The GT must be used to drive a propeller/water jet/generator. Because of this requirement we may consider the marine GT to be split into two main parts.

·         The gas generator- that providing the high energy gas stream.

·         The power producer- that converting the energy in the stream into a useful form of power eg shaft power(power turbine)

Hence it is possible to adapt an aircraft engine for  marine use by the addition of a power turbine eg Olympus SMIA.

In addition marine GTs are not nearly so restricted for space as the aero versions and therefore it is theoretically possible to attempt to improve the performance by using one or more of the following:

• Intercooling
• Reheat
• Heat exchanger
• Water injection
• Waste heat recovery

REASONS FOR THE ADOPTION OF GAS TURBINE

1. The aim to be able to explain the reasons why the royal navy and other navy is adopted gas turbines as main propulsion units in major surface warships, the typical problems associated with running them at sea and their solutions.

1. The resons for using gas turbine in warships:

·         High power/weight ratio.

·         Quick startup capability

·         Comparatively low development cost.(benefits from aero engine development)

·         Low onboard maintenance requirement.

·         Ease of upkeep by exchange of critical parts.

·         Reduced watchkeeping manpower.

·         Good SFC at high power.

·         Availability

·         Reduced underwater noise(fewe hull openings)

1. Typical problems and solutions

·         Distortion of combustion chambers- ongoing design effort, regular inspection.

·         Combustion of naval fuels-redesign of combustion system.

·         Compressor fouling-air filtration, regular washing.

·         Surge and rotating stall- air bleeds, variable geometry blades.

·         Turbine Disc failures – Design effort, defined service life.

·         Bearing failures- Uprated bearings, earlier detection of possible failure.

·         Fuel consumption at part load- multispool variable geometry engines, higher operating temperature.

·         Practical problem of a complex cycle- no solutions at present.

·         Poor life of aero types –rapid engine change capability-comprehensive repair/rebuild facilities, life continually being upgraded.

Oil lubricated stern tubes

Progress from sea water to early oil lubricated stern tubes involved exchange of the wood lined bronze carrierfor a while metal lined, cast iron bush. oil retention and exclusion of sea water. necessitated the fitted of an external face type seal. The stuffing box was returned in many early oil lubricated stern tubes at the inboard end.
the latter designs with an extended length boss built into the stern frame provide better support for the white metal lined
bearing. A minimum bearing length of two times the shaft diameter will ensure that bearing load doesnot exceed 0.8 N/MM2

the tube is fbricated and welded direct to the extension of the stern tube frame boss at the after end and to the aft peak bulkhead at the forward end.

oil contaminated with in simplex type stern tube by lip seal. The elastic lip of each nitrile rubber seal liners at outboard and inboard end of the steel propeller shaft.
The outboard liner additionally protects the steel shaft from sea water contact and corrosion.

Heat produced by the friction will result in hardening and loss of elasticity of the rubber, should temperature of the seal material exceed 110c. cooling
at the outboard end is provided by the sea. Oil circulation aided by convention, is arrranged to maintain low temperature of seals at the inboard end.
connections  are fitted top and bottom between the two inboard seals.

The chrome steel liners act as rubbing surfaces for the rubber lip seals and grooving from fricitional wear has occurred. The problem has been overcome by using a ceramic
filler for the groove or alternately a distance piece to axially displace the seal and ring assembly. Allowance must be made for relative movement of shaft and stern tube due to
differential expansion. New seals are fitted by cutting and vulcanizing in position.

Lip seals will accept misalignment but a floating ring design was introduced by one maker.

Marine Gas Turbines

In the name of ALLAH who is the most beneficient and merciful

Marine Gas Turbine (GT)

AN INTRODUCTION TO MARINE GAS TURBINE

The aim is to be able to identify and explain the function of gas turbine major engine component and discuss the mode of operation of simple and complex cycle gas turbine engines compared with diesel and steam plant.

Definition of a Gas Turine

A continuous cycle self contained heat engine using a gas as the working fluid.

Breakdown of definition

1.      Energy output. After providing the power to drive the compressor(self contained) the energy output may be in the form of :

·         Jet thrust

·         Shaft power

·         Compressed air from compressor

·         Heat

2.      Self contained. Once running it is not dependent on any other machine.

3.      Gas may be.

·         Air – Open cycle

·         Hydrogen, helium etc closed cycle . In this case heat is added by means of a heat exchanger.

4.      Energy source. This may be provided by

·         Oil fuel

·         Natural gas

·         Sewage gas

·         Waste gas

·         Waste heat (eg blast furnance)etc .

5.      Compressor. This is usually either axial or centrifugal, but free piston and reciprocating compressor have been tried, although the process then is no longer continuous.

6.      Continuous. Unlike a diesel which operates with gas in a similar way the GT uses a constant pressure process which is continuous.

Comparison of cycles

In the services we are concerned with three main forms of providing power (see below). These all have particular advantages and disadvantages, some of which can be readily appreciated by a quick comparision of the ideal cycle on a T-S chart.

The following factors show themselves:

1)      Steam Plant

• Operates across saturation envelope.
• Closed cycle – recovery process needed to condense and re-use steam, hence much additional machinery.
• Small work to compress fluid. Good work from expanding vapour- large exess.

2)      Diesel

·         Fairly good available work output after compressing gas.

·         Open cycle.

·         Non-continuous cycle means valves and moving parts. Stress problems.

3)      Gas turbines

• Very poor specific work output available after compressing gas. High powers only available if:
• Component efficiencies high
• High mass flow
• High mass flow possible because process is continuous.

Conclusions

From the above comparisons the factors which stand out about gas turbines are:

• Unlike The others, an overall power output is possible purely because the constant pressure lines diverge with increase in entropy.
• Its specific output is very small and dependent upon the efficient operation of the various components. Mass flows are high hence small increases in component efficiencies will give relatively large increases in output.

Marine gas turbine  (GT)

An aircraft can use the energy in the gas stream directly to provide the propulsive power eg in a jet. In the marine environment this is not feasible because of the very nature of the surroundings , the noise, the requirement to reverse and limitations imposed by the construction of the ship. The GT must be used to drive a propeller/water jet/generator. Because of this requirement we may consider the marine GT to be split into two main parts.

·         The gas generator- that providing the high energy gas stream.

·         The power producer- that converting the energy in the stream into a useful form of power eg shaft power(power turbine)

Hence it is possible to adapt an aircraft engine for  marine use by the addition of a power turbine eg Olympus SMIA.

In addition marine GTs are not nearly so restricted for space as the aero versions and therefore it is theoretically possible to attempt to improve the performance by using one or more of the following:

• Intercooling
• Reheat
• Heat exchanger
• Water injection
• Waste heat recovery

REASONS FOR THE ADOPTION OF GAS TURBINE

1. The aim to be able to explain the reasons why the royal navy and other navy is adopted gas turbines as main propulsion units in major surface warships, the typical problems associated with running them at sea and their solutions.

1. The resons for using gas turbine in warships:

·         High power/weight ratio.

·         Quick startup capability

·         Comparatively low development cost.(benefits from aero engine development)

·         Low onboard maintenance requirement.

·         Ease of upkeep by exchange of critical parts.

·         Reduced watchkeeping manpower.

·         Good SFC at high power.

·         Availability

·         Reduced underwater noise(fewe hull openings)

1. Typical problems and solutions

·         Distortion of combustion chambers- ongoing design effort, regular inspection.

·         Combustion of naval fuels-redesign of combustion system.

·         Compressor fouling-air filtration, regular washing.

·         Surge and rotating stall- air bleeds, variable geometry blades.

·         Turbine Disc failures – Design effort, defined service life.

·         Bearing failures- Uprated bearings, earlier detection of possible failure.

·         Fuel consumption at part load- multispool variable geometry engines, higher operating temperature.

·         Practical problem of a complex cycle- no solutions at present.

·         Poor life of aero types –rapid engine change capability-comprehensive repair/rebuild facilities, life continually being upgraded.

Next topic

Scavenge Fire

List the various factors which must be present for a scavenge fire to start?

For any fire to begin there must be present a combustible material, oxygen or air to support combustion and a source of heat of a temperature high enough to start combustion. In case of scavenge fires the combustible material is oil. The oil is usually cylinder oil which has drained down from the cylinder material is oil. The oil is usually cylinder oil which has drained down from the cylinder spaces, in some cases the cylinder oil residue may also contain fuel oil. The fuel may come from defective injectors, injectors with incorrect pressure setting, fuel particles striking the cylinder, and other similar causes. The oxygen necessary for combustion comes from the scavenge air which is plentiful supply for the operation of the engines. The heat in the scavenge space, around the cylinder, brings the oil to a condition where it is easily ignited. The high temperature required to start combustion may arise from piston-ring blow past.

How would you become aware of a scavenge fire? How would you deal with a scavenge fire?

The first indication of a scavenge fire may be a slight reduction in the engine speed due to the reduction in power which comes about when a fire starts. Other indications are a higher exhaust temperature at the cylinders where the scavenge fire has started and irregular speed of turbo-blowers. External indications will be given by a smoky exhaust and the discharge of sooty smuts or carbon particles. If  the scavenge trunk is oily the fire may spread back from the space around or adjacent to the cylinders where fire started and will show itself as very hot spots on areas of the scavenge trunk surfaces. In ships where the engine room is periodically unmanned, temperature sensors are fitted at critical points within the scavenge spaces. On uniflow-scavenged engines the sensors are fitted round the cylinder liner just above the scavenge ports. A temperature higher than reference or normal then activates the alarm system.

If a scavenge fire starts, two immediate objectives arise; they are to contain the fire within the scavenge space of the engine and to prevent or minimize damage to the engine. The engine must be put to dead slow ahead and the fuel must be taken off the cylinders affected by fire (see note). The lubrication to these cylinders must be increased to prevent seizure and all scavenge drains must be shut to prevent the discharge of sparks and burning oil from the drains into engine rooms. In allows the fire to burn itself out without damage. Once the fire is out and navigational circumstances allow it, the engine should be stopped and the whole of the scavenging port examined and any oil residues found round other cylinders removed. The actual cause of initiation of the fire should be investigated. If the scavenging fire is more major nature. It sometimes become necessary to stop the engine and use the steam or extinguishing arrangement fitted to the scavenging trunk. The fire is then extinguished before it can be spread to surfaces of the scavenging trunk. Where it may cause the paint to start burning if special non-flammable paint has not been used.

 How can the incidence of scavenge fires be prevented or reduced?

One of the first things that must receive attention is maintaining the scavenge space in as clean a condition as possible. This can be done by keeping scavenge drain pipes clear and using them regularly to drain off any oil which comes down into scavenge space drain pockets. The scavenge space and drain pockets should also be cleaned regularly to remove the thicker carbonized oil sludge which don’t drain down so easily and which are a common cause of choke drain pipes. The piston rings must be properly maintained and lubricated adequately so that ring blow-by (blow-past) is prevented. At the same time one must guard against exceed cylinder oil usage. With timed cylinder oil injection the timing should be periodically checked. Scavenge ports must be kept clear.

The piston-rod packing ring and scraper rings should be regularly adjusted so that oil is prevented from entering

 NEXT TOPIC

Fuel consumption and efficiency

 In merchant ships the optimum design, maximum thermal efficiency and minimum fuel consumtion are arranged for full power condition. Specific consumtion is much higher when speed are at maximum. In IC engines such as diesel generators has peak thermal efficiency at 70% of maximum load. When all units developing equal powers. The power estimation method provides fuel consumption values. The rate of fuel consumption is the amount of fuel used in a unit time eg. Tonne/day.

Since fuel consumption @ power

Where   power= tone2/3 x V3

                        _____________

                        Admiralty coefficient

Then fuel consumtion/day=_displ2/3 x v3_______________

                                                Fuel coefficient

 REFRIGERANTS

R12 CCL2F2 FREON 12
R22 CHCLF2 FREON 22
R502 CHCLF2/CCLF2CF3

FOR FREON 12
ACTUAL REFRIGERATION EFFECT = 400 KJ/M3  
COMPRESSION HEAT= 66KJ/KG

FREON 11 (VERY LOW PRESSUREFRERIGERANT ; SUITABLE FOR LARGE AIR CONDITIONING INSTALLATIONS)

FREON 22 (SUITABLE FOR LOW TEMPERATURES WITHOUT NEGATIVE EVAPORATOR PRESSURE IN VACCUM)

FREON 502 (FOR HERMETIC I-E INTEGRAL GAS TIGHT MOTOR AND COMPRESSOR)

THERE IS NO IDEAL CHOICE IN THE FREON GROUP AS THERE ARE ADVANTAGES AND DISADVANTAGES FOR R11 ( CC;3F)

FOR GOOD HEAT ENERGY TRANSFER RATE AT A TEMPERATURE DIFERRENTIAL OF ABOUT 8DEGREES BETWEEN COOLING WATER INLET AND CONS\DENSATION TEMPERATURE IS USUAL.

WRITTEN BY S/C ZEESHAN AHMED (A/C 2988)
INSTRUCTOR: CHIEF ENGINEER TAHIR JAMIL
DATE: 25/10/2009
TIME: 10:05:00 AM

  
 

Control Engineering

The closer control of machinery operating conditions, eg cooling water temperature and pressure, permits machinery to be run at its optimum design conditions, making for fuel economy and reduced maintenance.

Automation can carry out some tasks far more effectively than men in other areas it is less effective. For example, the monitoring of machinery operating conditions such as temperatures and pressure can be carried out by a solid-state alarm scanning system at the rate of 400 channels/sec giving a degree of surveillance wihcih would be impossible by human observation. Conversely the detection of a noisy bearing a leaky gland or a cracked pipe is scarcely possibly by automatic means. The balance between the possible and the necessary would be achieved in this case by combining automatic monitoring of all the likely fault conditions, with routine machinery space inspection say twice daily.

Classification societies

The class notation of a ship granted by a classification society, is a mark of approval of its standard, and it indicates that the vessel has been built to specific rules and thereafter periodically surveryed. It is the practice to include in the notation a special mark for ships designed to operate with periodically unmanned engine rooms, e.g. Lloyds Register add U.M.S. to the 100A1 notation to signify approval of operation with unattended machinery spaces.

The granting of special notations is also subject to the ship being built in conformity with rules or recommendations concerning automation. The principal international classification societies are Lloyds Register of Shipping, the American Bureau of shipping, Detnorske Veritas, Bureau Veritas and Germanischer Lloyd.

CONTORLS FOR GENERATORS

In unattended machinery installations it is necessary to provide certain control facilities for the electrical generating plant. These may vary from simple load sharing and automatic starting of the emergency generator, to a fully comprehensive system in which generators are started and stopped in accordance with variations in load demand.

Medium-speed propulsion plants normally use all-diesel generating plant. Turbine ships obviously use some os the high quality steam generated in the main boilers in condensing or back pressure turbo charger generators, with a diesel generator for harbour use. The usual arrangement on large-bore diesel propulsion systems is a turbogenerator employing steam generated in a waste-heat boiler, plus diesel generator for manoeuvring, port duty, and periods of high electrical demand.

Diesel generators

The extent of automation can range from simple fault protection with automatic shut-down for lubricating oil failure, to fully automatic operation. For the latter case the function to be carried out are:

1. Preparation for engine starting
2. Starting and stopping engines according to load demands
3. Sychronisation of incoming sets with supply
4. Circuit breaker closure
5. Load sharing between alternators
6. Maintenance of supply frequency and voltage
7. Engine/alternator fault protection
8. Preferential tripping of non essential loads

When diesel generators are arranged for automatic operations, it is good policy to arrange for off-duty sets to be circulated with main engine cooling water so that they are in state od readiness when required. Pre-starting preparations are then simply limited to lubricating oil priming.

It is necessary to provide fault protection for lubricating oil and cooling services, and in a fully automatic system these fault signals can be employed to start a standby machine, place it on line, and stop the defective set. In some installations, automatic controls carry out the sequence as far as synchronisation, and leave final circuit breaker closure to the engineer.

Turbo-generators

The starting and shut-down sequences for a turbo-generator are more complex than those needed for a diesel-driven set, and fully automatic control is therefore less frequenctly encountered. However, the control facilities are often less frequently encountered. However, the control facilities are often centralized in the control room, together with sequence indicator lights to enable the operator to verify each step before proceeding to the next. Interlocks may also be employed to guard against error.

The start up sequence given below is necessarily general, but it illustrates the principal and may be applied to remote manual or automatic control:

• Reset governor trip lever
• Reset emergency stop valve
• Start auxiliary L.O. pump
• Start circulating pump
• Apply gland steam

1. Start extraction pump
2. Start air ejectors
3. Open steam valve to run-up turbine

Where a waste heat boiler (economizer- a word form economy) is used to supply steam to a turbo-alternator, control of steam output is normally controlled by a three way valve in the exhaust uptake, the position of which is regulated in accordance with steam demand. Surplus waste-heat is then diverted to a silencer.

Conditions of assignment

In the name of ALLAH who is the most beneficient and merciful.

Conditions of assignment

The load line rules are based on the very reasonable assumption that the ship is built to and maintained at a high level of structural strength and will sail in a safe and seaworthy condition.

Until recently the rules laid down the standard of longitudinal and transverse strength. The classification societies usually found it necessary to increase these standards although in some design considered the rules excessive. It is now felt that the structural strength of the ship is more properly the function of the classification societies who may well be the assigning authority.

Standards of stability are given in the rules for both small and large angles of heel. Details of the information required to be carried on a ship are stated, together with typical calculations, all the information is based on an inclining experiment carried out on the completed ship in the presence of a DTp surveyor.

It is essential that all openings in the weather deck are water tight. Hatch coamings, hatch covers, ventilator coamings, air pipes and doors must be strong enough to resist the pounding from the sea and standards of strength are laid down. The rules also specify the height of coamings, air pipes and door sills above the weather deck, those at the force end being higher than the remainder.

It is important to remove the water from the deck quickly when a heavy sea is shipped. With completely open decks, the reserve buoyancy is sufficient to lift the ship and remove the water easily. When the bulwarks are fitted, however, they tend to hold back the water and this may prove dangerous. For this reason openings knows as freeing ports are cut in the bulwarks, the area of the freeing ports depend upon the length of the bulwark. If the freeing ports are wide, grids must be fitted to prevent crew being washed overboard. In addition, scuppers fitted to remove the surplus water from the deck. The scuppers on the weather deck are led overboard whilst those on intermediate decks are may led to bilges or, if automatic nonreturn valves are fitted, may be led overboard.

Type A ships, with their smaller freeboard are more likely to have water on the decks and it is a condition of assignment that open rails be fitted instead of bulwarks. If the vessel has midship accommodation, a longitudinal gangeway must be fitted to allow passage between the after end and midships with out setting foot on whether deck. In larger ships it is necessary to fit shelters along the gangway. Alternatively access may be provided by an underdeck passage, but while convenient for bulk carriers could prove dangerous in oil tankers.




WRITTEN BY S/C ZEESHAN AHMED (A/C 2988)
INSTRUCTOR: CHIEF ENGINEER YASEEN SAHAB
DATE: 25/10/2009
TIME: 10:05:00 AM

Life Savings Appliances

In the name of ALLAH who is the most beneficient and merciful.

Life Savings Appliances
The life savings equipment carried on board a ship depends upon the number of persons carried and the normal service of the ship. A transatlantic passenger liner would carry considerably more equipment than a coastal cargo vessel.

There must be sufficient life boat accommodation on each side of the ship for the whole of the ship’s complement(number/quantity that make something complete). The lifeboats must be at least 7.3 long and may be constructed of wood, steel, aluminium or fiberglass. They carry rations for several days, together with survival and signaling equipment such as fishing lines, first aid equipment, compass, lights, distress rockets and smoke flares. One life boats on each side must be motor driven.

The lifeboats are suspended from davits which allow the boats to be lowered to the water when the ship is heeled to 15 degrees. Most modern ships is heeled to 15 degrees. Most modern ships are fitted with gravity davits, which when released allow the cradle carrying the boats to run out board until the boat is hanging clear of the ship’s side.(fig.1)

The boat is raised and lowered by mean of an electrically driven winch. The winch is manually controlled by a weighted lever(fig.2) know as dead man handle which releases the main brake. Should the operator lose control of the brake the lever causes the winch to stop. The speed of descent is also controlled by a centrifugal brake which limits the speed to a 36 m/min. Both the centrifugal brake and the main brake drum remain stationary during the hoisting operation. If the main power fails while raising the boats, the main brake will hold the boat.

Each member of the crew is supplied with a lifejacket which is capable of supporting an unconscious person safely.

Lifebuoys are provided in case a man falls overboard. Some are fitted with self igniting lights for use at night and others fitted with smoke signals for pin-pointing positin during the day

Class 4 MEO Combined from Various Sources (India, UK, Pakistan, Australia, Malaysia)

Angola Navy Says Missing Tanker Located, Crew Faked Pirate Attack

From Dynacom FB seafarer club 

Good news, find below msg on dynacom web site, Update 2. Sunday 26 January 2014, 1500 UTC

Communication with "KERALA" has been re-established. 

All crew are safe and accounted for.

Pirates hijacked the vessel offshore Angola. The pirates stole a large quantity of cargo by STS transfer. The pirates have now disembarked.

Dynacom is committed to the safety of the crew, environment and the vessel and is dealing with the incident in conjunction with the relevant authorities.

Some more reading about this 

Jan 24 2014

Dynacom’s LR1 ‘Kerala’ was thought to have been hijacked by pirates off Angola.
The shipmanagement concern confirmed that communication with the ‘Kerala’ was lost on 18th January.

It was suspected that pirates had taken control of the vessel but this had not been confirmed, Dynacom said in a statement.

”Since then, we have taken immediate actions and working together with authorities/agencies for establishing communication, with the vessel,” the statement said.

The 74,998 dwt 2009-built tanker was thought to have disappeared while fully loaded with gas oil. She was last seen 150 miles off the Angolan coast.
In May, 2012, Dynacom’s 157,000 dwt Suezmax ‘Smyrni’ was the last ship successfully taken by Somali pirates. It was released after a ransom payment.
In a warning to members, Skuld quoted security concern Dryad Maritime as saying that suspiscious activities have recently been observed off the Angolan coast.
If the hijacking is confirmed, this means that Nigerian pirates are trying to extend their maritime zone to reach easier targets, ie ships that are not implementing protection against piracy, the insurance/P&I service concern warned.
Meanwhile, on the other side of Africa, pirates attacked a Navios-controlled LR1 about 115 miles south of Salalah, Oman.
This attack occurred during the evening of 17th January.
According to the International Maritime Bureau (IMB); "Pirates in a skiff, launched from a mother vessel, approached and fired upon a product tanker underway. Master raised alarm, increased speed, altered course, activated SSAS, contacted UKMTO and the non-essential crew members mustered in the citadel. The on board armed security team returned fire resulting in the pirates aborting the attack. A coalition helicopter came to the location to assist."
The vessel was identified as the Navios Tankers managed, 2013-built, 74,695 dwt, Marshall Islands flag, ‘Nave Antropos’.
A Japanese naval vessel- ‘Samidare’ -was conducting merchant vessel escort duties through the Internationally Recommended Transit Corridor (IRTC) in the Gulf of Aden in support of the Combined Maritime Forces (CMF) Combined Task Force (CTF) 151 when UKMTO received the report of the attack.
‘Samidare’ responded by heading towards the tanker and launched her helicopter to search for the pirate dhow ‘mother’ ship. Those on board the tanker at the time of the incident were reported safe and the vessel was able to resume her westbound voyage.
In co-operation with a Japanese Maritime Patrol aircraft, ‘Samidare's’ helicopter found the dhow and passed its location to the EU NAVFOR flagship, the French naval vessel ‘Siroco’. ‘Siroco’ was then able to sail towards the dhow and launch its helicopter and boarding team.
The EU NAVFOR Force Commander, Rear Admiral Hervé Bléjean, said: "Thanks to an exceptionally effective international co-operation, we showed once more that there will be no safe haven for piracy in the area as long as counter piracy forces remain fully dedicated to their task. I also congratulate ‘Siroco’ with this success."

From other source:

Angola’s navy said on 26th January that the crew of an oil tanker that vanished off its coast on Jan. 18 had turned off communications to fake an attack, seeking to calm energy sector fears that the vessel had been hijacked by pirates.

Unconfirmed reports that the tanker had been seized raised concern that piracy off West Africa was spreading south from the Gulf of Guinea, near Africa’s biggest oil producer Nigeria, where most hijacking gangs are believed to originate.Pirate attacks jumped by a third last year off West Africa. Any attack off Angola, which is the continent’s No. 2 crude producer, would be the most southerly to date.
Captain Augusto Alfredo, spokesman for the Angolan navy, said the missing Liberian-flagged MT Kerala has been located in Nigeria and that reports of a hijacking were false.
“It was all faked, there have been no acts of piracy in Angolan waters,” he told Reuters. “What happened on Jan. 18, when we lost contact with the ship, was that the crew disabled the communications on purpose. There was no hijacking.”
Alfredo declined to comment on how the navy had established the behaviour of the MT Kerala’s crew, saying only that other authorities may provide further details later.
He also would not be drawn on the crew’s possible motivation but said the ship, owned by Greece-based Dynacom, had been due to finish a time-charter contract for the Angolan state oil firm Sonangol on Feb. 12.Sonangol said on Friday the MT Kerala had 27 crew, all of them Indian or Filipino.
Alfredo said a tugboat had contacted the tanker in Angolan waters and then led it to Nigeria. The tugboat is a replica of one involved in a pirate attack off Gabon last year, he said.An SOS raised by another tanker in Angolan waters saying it was under attack from pirates on Friday was also a false alarm.
“The navy and the air force went to the location and did not find any signs of an attack. We want to know if this was a diversion tactic and will remain alert as there may be some forces manoeuvring behind these acts,” Alfredo said.