Saturday, November 22, 2014

Deck Seal

Deck Seal (type: semi dry)
The above image is of tanker ship. In the image you can easily see the semi dry deck seal. In this article I am going to explain how this deck seal work. The IG (inert gas) which is treated flue gas of boiler combustion is go through the deck seal. Deck seal also act as a non-return valve. Before the non-return Isolation valve is also provided. The pressure in the deck line is measured in millimeters of Wg (water gauge) or in short (mmWg). In the normal condition water is flowing in deck seal by the help of weir integrated in the deck seal. This weir has essential purpose maintain a level of water in deck seal. When IG is not coming or generating from Engine Room (E/R) the Kinematic Valve is open. Also the water to present in U bend (or seal of pipe). As soon as the IG comes it closes the kinematic valve also displaces the water present in the U bend and then goes out from deck seal above pipe  I will draw a line of grey color that will show the path when IG is passing through deck seal. Also I will show what will be the case if IG is not passing.




The mounting on our ship of deck seal are
1.       Float switch
2.       SW Inlet and Outlet
3.       Steam Inlet and Outlet
4.       Drain Valve
5.       Kinematic Valve
6.       Sight Glass (It must be half of glass)
7.       Outlet line for sea water (it is going in Pump Room) I think so.

Saturday, November 8, 2014

Pipelines MT KARACHI for OMAN Dry Dock

Following was the diagram of Pipelines MT KARACHI for OMAN Dry Dock. The dimensions i have to taken are 

INLET DIAMETER
OUTLET DIAMETER
LENGTH
FLANGE DIAMETER
FLANGE THICKNESS
PITCH CIRCLE DIAMETER
NUMBER OF HOLES

OTHER INFORMATION

DISTANCE BETWEEN PIPES ETC



COPT CIRCULATING PUMP

DRAIN COOLER INLET LINE

FIRE & BILGE BALLAST PUMP

MAIN ENGINE AIR COOLER

STRAINER FLANGE

MAIN COOLING SEA WATER PUMP  NO. 2

MAIN COOLING SEA WATER PUMP NO. 1



Monday, October 20, 2014

AUTOMATIC UNLOADING SYSTEM



1.General
This system is provided to improve the efficiency of stripping work. It can perform complete stripping work by the cargo oil pump (hereinafter called “pump”) alone.
The features of this system are as follows:
(1)Since most of stripping work is automated, pump operation is very easy.
(2)Since stripping work can be done by large capacity pumps alone instead of conventional small capacity reciprocating strip pumps, unloading time can be reduced.

2.Basic principle and actions
The basic principle of this system is to automatically prevent the suction of gas into the pump. By doing so, the completion of stripping by the pump alone becomes possible.
(1)Removal of gas from pump suction pipe
The gas sucked in from the suction bell-mouth and the cargo oil vapour produced in the suction pipe are separated from the cargo oil in the separator  and gathers at the upper part. These gases are extracted by the vacuum pump out of the top of the separator.
Discharge control valve (hereinafter called “discharge valve”) for preventing pump from sucking in gas.
When a large volume of gas comes into the separator  in the stripping stage, its liquid level becomes very low.
When a large volume of gas is sucked into the pump, pumping becomes impossible.
In order to prevent this condition, the discharge valve is controlled to the degree corresponding to the liquid level in the separator (hereinafter called ”separator level”) and the pump discharge flow is adjusted.
When the separator level falls excessively, the discharge valve is throttled to decrease the sucking amount of gas from the bell-mouth and it prevents the suction of gas into the pump.
When the separator level falls below the minimum set value , the discharge valve is fully closed.

3.Function of components
(1)Separator
This is tank to separate the gas sucked in through the bell-mouth and the cargo oil vapour produced in the suction line from cargo oil. The separated gas is extracted by the vacuum pump through the gas extraction pipe connected to the top of the separator.
(2)Level transmitter
This is consisted with main body (differential pressure measuring portion and pneumatic signal converting portion) and low/high pressure detectors (diaphragm seal type).Pressure detector is connected with main body via lead(filled with sealed liquid) and low/high pressure detectors are fitted to upper and lower part of separator. Static pressure (basic pressure) of sealed liquid of lead and static pressure of separator liquid level which is transmitted from high pressure side diaphragm are acting to the main body. The gas pressure in the separator acts evenly on both sides of the low/high pressure detectors and thus its effect is cancelled, so that the main body only measures the differential pressure of both static pressures. This measured differential pressure is converted into pneumatic  signal as a separator level and transmitted to cargo control console.
(3)Discharge valve
This is of butterfly type valve driven by pneumatic cylinder and controls the pump discharge capacity. This valve is remote-controlled by the valve opening signal (automatic control or manual control signal) from A/M selector.


(4)Valve position transmitter
This transmitter, which is installed on the discharge valve , converts the opening of discharge valve into pneumatic signal and transmits it to the valve position gauge on the cargo control console.
(5)Vacuum pump
This is of horizontal water ring type. This is driven by the motor through the intermediate shaft which passes through the bulkhead, and extracts the gas separated in the separator  and discharge it to the slop tank.
This pump is automatically started and stopped by the pressure switches which are operated by the pneumatic signal from the level transmitter.
By means of the control switch, manual start and stop can be also made.
(6)Sealing water tank
This is tank to separate the gas from sealing water which is discharged from vacuum pump and to hold the sealing water necessary for the vacuum pump function.
(7)Suction valve
This is of screw-down check angle valve fixed on the suction flange of vacuum pump.
When the vacuum pump stops, this valve closes to prevent sealing water and gas from flowing back to the gas extraction line.
(8)Gas extraction valve
This is of pneumatically operated piston type installed on the gas extraction line and is opened and closed by the solenoid valve control led through the pressure switch.
This valve is in the same system as the automatic start and stop circuit of vacuum pump and opens when separator level is less than 50% and closes when it returns to 100% or more.
(9)A/M selector
This is used to change over the discharge valve to automatic or manual control. By setting the A/M selector at “MANUAL”, it can be remotely operated by manual loader to get any opening.
(10)Solenoid valve
The valve is controlled by the pressure switches operated through the pneumatic signal from the level transmitter, and opens and closes the gas extraction valve by changing over the gas extraction valve operating pneumatic line.
(11)Positioner
This is fitted on the discharge valve and it corresponds the discharge valve opening to the opening signal from the A/M selector.
(12)Booster relay
The booster relay, which are provided on the open side and shut side of pneumatic cylinder respectively, change over the loading pneumatic line of pneumatic cylinder through the pilot signal transmitted from the positioner to open or close the discharge valve.
(13)Lock valve
This is fitted on the discharge valve and it locks the discharge valve opening in case of the driving air pressure drops abnormally low.
(14)Speed controller
The speed controllers, which are provided on the open side and shut side of pneumatic cylinder respectively, controls the opening/closing speed of the discharge valve.

4.Operating procedure of system (AUS)
(1)While the liquid level in the cargo oil tank (hereinafter called tank level) is high, this system does not work.
(2)As the tank level falls, the suction pressure also falls and approaches the vapour pressure of the pumping liquid.In this case part of the pumping liquid will turn to vapour  and accumulates in the top of the separator and as a result the separator level begins to fall.
(3)When the separator level falls down to below 50%, the pressure switch is actuated by a pneumatic signal from the level transmitter and the vacuum pump starts. At the same time , the gas extraction valve opens and the discharge valve is throttled.
(4)When the separator level recovers above 70%, the gas extraction valve closes and 10 seconds later, the vacuum pump ctops.
The discharge valve opens.
(5)Every time the vapour of pumping liquid accumulates in the separator top, the above mentioned conditions (3) and (4) are repeated and thus the unloading work is advanced while the suction of gases by the pump is being prevented.
(6)When the tank level further falls (e.g. when the bottom longitudinals of the hull appear above the oil surface), eddy begins to occur around the bell-mouth. Soon, when the bottom of the depression of this eddy (gas column) reaches the bottom face of the bell-mouth, gas begins to be sucked into the bell-mouth.
(7)The gas sucked in is separated from the pumping liquid in the separator and accumulates in its top, lowering the separator level. Hereupon the action described in (3) and (4) above is repeated.
(8)When the tank level further falls, the liquid surface around the bell-mouth comes to wave violently and a large volume of gas comes to be sucked in directly from the bottom face of the bell-mouth. Under such condition, even though the vacuum pumps are operated, the separator level falls to a great extent.
(9)As a result, the signal air pressure of the level transmitter falls excessively, greatly reducing the opening degree of the discharge valve, namely the pump discharge flow decreases considerably.
In consequence, the speed of the pumping liquid flowing into the bell-mouth decreases and the wave motion of the liquid surface around it becomes small.
Thus the volume of the gas sucked into the bell-mouth decreases.
(10)When the volume of the gas sucked in becomes less than the, extraction capacity of the vacuum pump, the separator level begins to rise. At the same time the discharge valve opens gradually and the pump discharge flow begins to increase.
(11)As the result, the volume of the gas sucked in begins to increase again, the separator level falls and  the discharge valve is throttled.
(12)In this way the conditions described in (10) and (11) are repeated and the tank level further falls. During this time the vacuum pump is continuously operated.
(13)When the tank level falls excessively, the separator level falls excessively due to excessive volume of the gas sucked in and the discharge valve comes to be completely closed. Hereupon the separator level rises a little and as the discharge valve opens a little the volume of the gas sucked in becomes excessive again and the discharge valve  is completely closed again.
When the separator level becomes below 5%, the red lamp (LOW SEPARATOR LEVEL) lights, showing that the unloading work has entered the stripping stage.
(14)Thus, as the stripping of cargo tank advances, even though the vacuum pump is continuously operated, the separator level does not rise, as the result it so happens that the discharge valve remains completely closed from time to time.
(15)The continuation of this condition for a long time means that there is no residual liquid to be unloaded. When the red lamp (LOW SEPARATOR LEVEL) is ON for a certain (3mm.) the red lamp (COMPLETION OF STRIPPING) flickers and the buzzer sounds by each action of the pressure switch and time-lag relay, thus showing the completion of unloading work.



Saturday, October 18, 2014

VISITED TO DOCKYARD



                                          

Yesterday was our visit to dockyard we have seen the beautiful floating dock and the ice (Internal Combustion Engine) shop with pumps description in the premises of navy where there is a great restriction for the entry of mobile phone and the suicide bombers.

When entered the ice (internal combustion engine) shop, we have seen the beautiful environment of the shop with a proper precision and the decision which I think is control by a one command.

There the class was separate into two group se1 (Senior Engineering) and se2 (Senior Engineering).

Main discussion

V type engine with a 10 cylinders engine and we have seen a bench for the overhauling of engine which can be feasibly rotated.The overhauling included a 5 men working on an engine rating 750 kw 4 stroke diesel generator, top overhauling included the engine only the cylinder head and it related part.

The overhauling we have seen the liner piston have crown and skirt and the piping of water and lubricating and the oil sump, water jacket in which the fresh water is circulated, crankshaft is the most interesting part and there is a portable machine which is used to check the choke of a pipe.

In a separate room we have seen the atomizer and the fuel oil pump adjust machine.

In pump shop


We have seen the reciprocating, screw, centrifugal pump. They both have positive and negative displacement.

Screw pump have low suction but discharge is high; used for the high viscosity fuel like diesel engine.

Whereas roto dynamic centrifugal pump is high suction but low discharge pump.

WRITTEN BY: ZEESHAN AHMED
TIME AND DATE: 9:36PM & 19 FEB 2009.

Wednesday, October 1, 2014

MT Shalamar is soon going to add in current fleet.

Good news:

PNSC is going to buy fourth oil tanker which will be named SHALAMAR. Don't confused with the old MT Shalamar which was acquired in 2003 and scraped in 2007.
MT Shalamar19812003-2007Oil Tanker54474 GRT[30]Scrapped in 2007Built in Sanoyas Mizushima Works & Shipyard KurashikiJapan

This tanker is also going to buy from greek ship company named samos steamship. This company have 14 foreign going (FGN) tankers. The ship named Ambelos is now soon going to replaced by the Shalamar. Ambelos have the following 



IMO: 9336842
MMSI: 309884000
Call Sign: C6VS8
Flag: Bahamas (BS)
AIS Type: Tanker
Gross Tonnage: 55894
Deadweight: 105315 t
Length × Breadth: 228.6m ×42.04m
Year Built: 2006

OwnerNAFSIKA MARITIME SA
CategoryOil Carrier
SizeAframax
BuiltSumitomo / Japan
Year Built2006
DWT105315 M/T
L X B X D (m)228.6 X 42.00 X 21.50
Full Load Draught (m)14.78
FlagBahamas
ClassificationLR
I.M.O. Nr9336842
M/E:B&W 6S60MC-C
D/G:3x DAIHATSU 6DK-20
Cargo Segregations3
Double HulledYes
No. of Cargo Tanks13 (Slop Tanks included)
No. of Ballast Tanks12
98% Capacity (m3)114719
Cargo Tank CoatingYes Partial
CoiledYes
Cargo Pumps3 Centrifugal steam turbine
COWYes
IGSYes
VECSYes

Wednesday, September 24, 2014

Safety Management and its Maritime Application




Safety is common term; applied in our daily life routine. This book is written by Professor Chengi Kuo on title “Safety Management and its Maritime Application”.  Professor has deep knowledge in maritime activities. He has done graduation from the University of Glasgow where he pioneered the application of computers to ship design and shipbuilding before gaining experience working in the USA on propeller excited vibration.

This book has 13 chapters. Examples from our daily life for example you are going to buy a flat for temporarily residency what are the point you will consider. What are your requirement 3 or 4 room with attached bath, TV launch, 01 store, large garage area and washing area. What is your budget? Is smoking allowed in the flat or not. Is smoke detector must be fitted on ceiling. Is there any need to re-paint the walls or it is not required at all.

You wanted to go uphill a mountain by a four wheel car drive. What are the risks that will involve? What paths you will choose? Is the road slippery or not? Is there any risk of snow falling at time you have to drive? What is the wind speed? What is temperature outside there? How is traffic at the road at which you have to travel? And many of the factors you have to consider? So on these points you will make your risk assessment when going for uphill mountain drive.

Similarly on aboard ship by gaining experience you make the risk assessment.

Read the book fully, you will definitely enjoy it.


Monday, July 14, 2014

Ramadan Aboard Ship

Yeah it’s an adventure when you are aboard ship at middle of the ocean with having a Ramadan. You may or may not clearly see the moon shining. The first day of the Ramadan may be a hectic one because of all the routine is going to change. As I am from Engine side, Junior Engineer, as suggest from rank it will be more donkey work for me. But be patience fruit will come out in next coming days. Yeah you will be more conscious, alert and give pardon to each other.

As the Ramadan start our routine is changed, normally the routine schedule follow on our ship is

1.       0800 hours day work started
2.       1200 hours noon break for lunch and namaz, rest (etc.)
3.       1300 hours go back to work
4.       1700 hours routine and UMS mode put on (but it is not normal on our ship our routine for pack up is normally 1800/1900 hours)
5.       2200 hours UMS (unmanned machinery spaces) round
6.       2300 hours UMS round completed
7.       Then again Manned @ 0800 hours

Occasionally we have Sunday half day otherwise work and work. That is a never ending term on SHIP.
Ramadan routine is quite different for engineer. Here’s up

1.       2100 hours day work started
2.       0300 hours normally ( Engine Room on UMS)
3.       Junior Engineer plus senior engineer have to take the round at 1100 hours to 1200 hours. Also 1700 hours its depend upon how you have done the routine.
For SEA and CARGO watches  the timing is same throughout the year.

For SEA
1.       0800 to 1200 hours (Shift A) Senior + Junior
2.       1200 to 1600 hours (Shift B) Senior + Junior
3.       1600 to 2000 hours (Shift C) Senior + Junior
SEA watches is as international standard 4 ON & 8 OFF.

CARGO watches is
1.       0800 to 1600 hours (Shift A) Senior + Junior
2.       1600 to 0000 hours (Shift B) Senior + Junior
3.       0000 to 0800 hours (Shift C) Senior + Junior

CARGO watches is not as international standard but it’s for relaxation. 8 ON & 16 OFF


Monday, February 3, 2014

MSB (Main Switch Board)

In the name of Allah most beneficent and merciful


In this article you will understand how Electricity is “generate and consume” aboard ship. The distribution principal is something same like in domestic purposes but there is a difference, no need of lengthy cable in ship. Only a kilometer / half kilometer is maximum length of cable running across the ship length. So very much high power generation plant system is not required on ship e.g. in MW. There are only some minor losses of electricity on board.
The alternator produces electricity which is then goes to the ECR (Engine Control Room) through bunch of wire from beneath of ECR. These wires then led to the rectangular bar at back of panel known as busbar.
The main advantage of these bars over the cable is that it can easily connect a Motor starter panel or any other kind of load. The main switch board now distribute into several other panel which are listed below.
1.       Feeder panel  No. 1 440 VAC
2.       Feeder Panel  No. 2 440 VAC
3.       Feeder Panel  No. 1 110 VAC
4.       Feeder Panel No. 2 110 VAC
5.       Generator Panel No.1 
6.       Generator Panel No. 2
7.       Generator Panel No. 3
8.       Synchronizing Panel
9.       Group Starter Panel No. 1 (440 VAC)
10.   Group starter Panel No. 2 (440 VAC)
11.   Earth Monitoring Panel
12.   Distribution Box Panel
Now in the bus bar we have 440 VAC coming from generator but for some machinery we required only 110 VAC.  So for this we have usually Air Cooled transformer. 
 Generator Panel No. 1
On Screen
The panel of generator must have essential parameter to display, the figure which are non-essential can be local displayed e.g. RPM, Boost Air (Scavenge air ) pressure, Sea Water pressure, Cooling water pressure, differential pressure. Normally on screen reading are Lube oil Pressure, Lube Oil In/Out, Jacket Water out temperature,

On Vertical Rack
Mostly Alternator side parameters are displayed on it. E.g.  Voltage, Current and Kilowatt. Selector switch for Voltage and current are given so that one can switch to other phase to check voltage and current are present on other phases.  Standby by button is also provided on the panel.
Some two more instrument are provided on the ship e.g. Synchroscope, Synchroscope selector switch, 
Then the electricity which are on bus bar is led to the Feeder panel No. 1, where Group starter panel of are present.

Generator to ACB

ACB to Bus bar

Bus bar to different load/panel (motor, etc)