Tuesday, January 14, 2020

Generator fuel oil system

Oil record book (ORB) codes

Monday, January 13, 2020

Generator evaluation of readings regarding combustion condition

Scuffing

Scuffing is a form of micro-seizure of Piston Ring when LO breaks down. 
Scuffing is caused due to; 
Bad Cylinder Lubricant 
Defective Cyl. Lubricator 
Insufficient LO Points 
No oil groove in liner 
Absence or wrong Scraper Rings.

Turbocharger cutting-off procedures:


» When it is necessary to cut-off T/C due to heavy vibration, bearing failure, etc. cutting 
procedure should be done as per engine maker’s instruction. 
» Cutting-off operation depends on number of T/C installed and number of T/C damaged. 
Following procedures are in accordance with Sulzer RT engine practice: 
Case I: Failure of one T/C, with Exhaust by-pass piping:
Lock rotor as per T/C manual. 
Remove blank flange in by-pass exhaust piping.
Open covers of scavenge air trunk. 
Auxiliary blowers must be running during operation. 
If casing is cracked, stop T/C cooling. 
If T/C is supplied with external lubrication, shut L.O. supply. 
 Output 25%: RPM 60% at MCR. 
Case II: Failure of one T/C, of two T/C engine:
Lock rotor of damaged T/C. 
Remove expansion joints of both exhaust inlet and air outlet of damaged T/C, 
and put blank flanges. 
If casing is cracked, stop T/C cooling. 
If T/C is supplied with external lubrication shut L.O. supply. 
 Output 50%: RPM 80% : Running T/C rpm must not exceed normal rpm: 
Case III: Failure of all T/C of an engine, without Exhaust by-pass piping:
Lock rotors of all T/Cs. 
Open all covers of scavenge air trunk. 
Auxiliary blowers must be running during operation. 
If casing is cracked, stop T/C cooling. 
If T/C is supplied with external lubrication shut L.O. supply. 
 Output 15%: RPM 50%:

Precautions before Entry into Empty Tank:

1. Gas freeing is essential before entering empty tank. 
2. Manhole doors to be opened for at least 24 hours before entry. 
3. Forced ventilation with air duct, to be done with electric blower, for at least 24 hours. 
4. With forced exhausting system, minimum of 2 air changes should be completed during 
that time. [For every dangerous space, 10 to 20 air changes are necessary.] 
5. After thorough ventilation, tank atmosphere tested for any toxic or explosive gases, by 
invited Chemist or with Safety Lamp before entering. [Flame will burn clearly, if free 
from foul gases. Faint blue cap will show presence of explosive gases. If burning black 
or flame goes out, it shows presence of CO₂ gas, which is fatal to life]. 
 When tested by Chemist, TLV must be taken as a standard. 
6. When the tank is gas free, following LSA to be carried or kept ready, when entering. 
a) Lifeline or harness to be put on. 
b) Spark proof hand torch to be brought in. 
c) BA set to be kept ready. 
d) Resuscitation equipment to be kept ready. 
e) Have rescue team, readily available and properly led. 
f) Competent person, stand-by at entrance. 
g) Agree a communication system, before entry. 
h) Have adequate illumination.

Crankcase Relief Door: SOLAS Regulation and Requirements:

An IC engine of over 200-mm bore or crankcase volume of 0.6 m³ and above, 
shall be provided with crankcase relief door with sufficient relief area.(Regulation) 
Opening pressure = 1/15 bar (0.07 bar) above Atmospheric pressure, but ≯ 3∼7 
bar of explosion pressure. 
Free area of each relief valve ≮ 45 cm². 
Combined area of relief valves ≮ 115 cm² per m³ of crankcase volume.

Fire control plan

Fire control plan: 
» General arrangement plan must be permanently exhibited onboard, for the guidance of 
officers. 
» Positioned outside the deck house [opposite to gangway of both sides] in a permanently
watertight enclosure for assistance of shore fire brigade. 
» Fire Control Plan includes: 
Fire control stations. 
Various fire sections, enclosed by both Class A and Class B divisions. 
Particulars of fire detection and alarm system. 
Sprinkler installation and fire extinguishing appliance. 
Means of escape. 
Ventilation system, including positions and numbers of fan controls and dampers. 
Fire Fighting Appliances, FFA: 
 
All portable and semi-portable extinguishers: Good working order ensured, properly

Types of detector

Smoke detector:
1.
2.
3.
4.
5.
6.
Installed at stairways, corridor, escape route within Accommodation Space. 
Also used in Cargo space and Machinery space 
Maximum floor area per detector = 74 m². 
Max. distance apart = 11 meters. 
Max. distance away from bulkhead = 5.5 m. 
Photocell or light scattering types. 
Heat Detector:
Maximum floor area per detector = 37 m². 
Max. Distance apart = 9 meters. 
Max. Distance away from bulkhead = 4.5 m. 
Used Bi-metal strip. 
Fitted in boiler room, laundry, Control Room, Galley. 

Flame Detector:

Ultra Violet or infrared. 
Fitted near fuel handling equipment. 

Combustible Detector:
Fitted in galley, ER fwd bulkhead adjacent to p/p room under floor plate.

CO2 calculation

CO₂ Quantity Calculation: (by Regulation): 
 
For cargo space, CO₂ quantity shall be sufficient to give a minimum volume of free gas, 
equal to 30% of gross volume of largest cargo space so protected. 
For machinery space, CO₂ quantity shall be sufficient to give a minimum volume of free gas, 
equal to 40% of gross volume of machinery space so protected excluding the casing. 
Weight of CO₂ / bottle = 45 kg / bottle. 
Free gas volume of CO₂ = 0.56 m³/ kg. 
 

Sludge content onboard is high, what to do?


Sludge, waste oil or oil and water mixture up to 25% of water content could be 
burnt in incinerator. 
Sludge can be disposed from ship to shore reception facility through International 
Discharge Connection, provided at discharge side of Sludge Pump. 
Transferred to another (other) tank. (Indicate tank and total content of tank) 
Incinerated amount, total time of incinerator operation, disposal of oil residue 
(sludge), quantity of retention, tank no. and its capacity, port name, item no. and 
letter code are to be recorded in ORB. (See page 164) 
Reception Certificate attached with ORB.

SOPEP requirement

SOPEP Requirements:
Oil spill kit inside Oil spill Locker:
Can be grouped into: Solvent Absorbent Cleaning Plugging material. 
1. OSD 200 litres. 
2. Chemical splash suit 10 nos. 
3. Goggle 10 pairs. 
4. Boots 10 pairs. 
5. Nitrile gloves 10 pairs. 
6. Sawdust and cotton rags. 
7. Oil seals 30 nos. 
8. Oil coushions 40 nos. 
9. Oil scoop (non-spark) 1 no. 
10. Deep pan shovel (non-spark) 1 no. 
11. Disposable bags 10 nos. 
12. 29 ft³ Container 2 nos. 
13. Bucket (non-spark) 1 no. 
14. Brooms 6 nos. 
15. Scupper plugs 
16. Cement for plugging 
17. Submersible pump (Wilden) 
18. Bilge and Ballast Piping Diagram. 
19. Fuel and LO system Piping Diagram. 
20. HO responsible address. 
21. Port Authority Address. 
22. Agent Address.

Generator load test


 
1. After priming the AE, start and run under no load, low speed condition for about 3 to 
5 min. 
2. Then stop and checked externally for overheating. If no overheating, crankcase doors 
to be opened and checked temperature of bearings and running gears. 
3. If satisfactory, restart the engine at full speed, no load condition for about 30 min., 
then stopped and recheck again. 
4. If satisfactory, restart and load-shared with running generator engine. Load sharing 
should be gradually increased in small steps, taking about 6 to 10 hours to reach at 
full load condition. While running in full load, another generator to be run in stand-
by for possible emergency use. Synchronising or load sharing steps: 25%, 50%, 
75%, and 100% within 6 to 10 hrs. 
5. All necessary items checked, during load increasing steps. 
6. Then peak pressure indicator and other performance data, taken for each cylinder and 
compare with test results. 
7. Load test should be done, until preferential trip initiates.

Sounding pipe requirements

Used to determine the dept of liquid in a tank. 
Should be as straight as possible. 
If it is not possible, pipe curvature should allow easy passage of sounding rod or 
chain. 
Normally, bore of pipe must be not less than 32mm. 
Striking pad of adequate size and thickness placed under the pipe

Condition for freeboard and its important

Efficient means of protection must be provided for all openings to hull and 
superstructure, for protection of crew in heavy weather, and for rapid freeing of water
from weather deck. 
2. Condition of Assignment must be maintained, at all times in satisfactory condition. 
3. Annual Inspection to be made by assigning authorities, to ensure that they have been 
maintained in satisfactory condition for continued validity of Load Line Certificate.

Reed valve

Reed valves are a type of check valve which restrict the flow of fluids to a single direction, opening and closing under changing pressure on each face. 
Modern versions often consist of flexible metal or composite materials 
Reed valves are commonly used in high-performance versions of the two-stroke engine, where they control the fuel-air mixture admitted to the cylinder.
 As the piston rises in the cylinder a vacuum is created in the crankcase beneath the piston.

Friday, January 10, 2020

Crankshaft deflections


Crankshaft Deflections And Wear Down Gauge Readings

  • In order to prevent crankshaft failure and serious breakdowns, it is absolutely essential to maintain the main bearings of an engine in true alignment.
  •  The alignment must be checked as per the maker’s instructions, with the main bearing bridge gauge, and the crankweb deflection gauge. In taking these measurements, extreme care must be taken to see that the journal is bedding on its bearing.
  •  The thickness of the lower half main bearing shells must also be measured and recorded. If the reduction in thickness of individual bearing shells is not uniform then the differences will be a true record of misalignment.

A chart is provided by the engine manufacturer that gives the various tolerances which may be allowed.

Inspections : Cylinder Liner Gauging:

  • The gauging of the cylinder liners must also be taken and recorded on the appropriate form. Abnormal wear rate must be investigated and reported to the superintendent.
  • Cylinder Liners are high cost components, it is important to monitor the specific lube oil consumption and wear rates closely.
  • Other calibrations required by the engine manufacturers must be taken at the appropriate intervals.


Crankcase inspections:

  1. Crankcase inspections must be carried out at, or within, the manufacturers’ running hours.
  2. In the case of air starting systems the main air starting line is to be drained and completely vented.
  3. Before a crankcase inspection is carried out the turning gear must be engaged, indicator cocks or other cylinder pressure relief devices opened and the air or other starting arrangements must be isolated.
  4.  In the case of smaller medium speed engines and high speed engines without turning gear the starting arrangements must be isolated, and cylinder pressure relief devices opened. 
  5. Within the scope of diesel engines from high speed through medium speed to slow speed types, there are a wide variety of arrangements for the running gear and bearings, and all must be examined in accordance with manufacturers’ instructions, however the following checks are to be carried out:
  6. Sump drain grids for blockage, metal, or other impurities.
  7. If appropriate to the engine type a lubricating oil pressure test is to be carried out.
  8. The adequacy of the flow of oil from the bearings, its direction and pattern are to be carefully observed and compared with the manufacturers’ instructions. This test can provide positive indications towards locating faulty bearings.
  9. Take feeler clearances according to manufacturers’ instructions.
  10. As appropriate to the engine type and to “built-up” crankshafts the proof marks should be examined for correct alignment. The relevant Management Office must be informed if there is any doubt concerning proof marks.
  • The running gear such as the crankshaft, main bearings, bottom end bearings, top end bearings, guides, astern bars, etc., must be examined as every opportunity occurs, preferably as soon as the crankcase is safe to enter, after the "finished with engines" order is given.

    In carrying out this examination, attention must be given to the locking arrangements and tightness of all nuts, lubricating oil pipes, piston cooling pipes and glands, if fitted, oil drainage arrangements, drainage lines etc. A sharp look out must also be kept for any sign of white metal flakes or splinters as these are often evident if any bearings have "wiped" or tended to "run".

    Attention must also be given to crankshaft coupling bolts. At three monthly periods the tightness of these nuts must be tested with a light hammer and spanner, care being taken so that the coupling bolts are not unduly stretched. The welding of main bearing girders must be examined for signs of cracking. Maintenance performed on the main engine in the Maintenance Report Form
  • The chains and/or gearing driving the camshaft must also be examined. The chains must be kept at the proper tension. It is essential that the crankcase doors are always replaced between overhauling periods when in port to ensure that as little moisture as possible condenses in the crankcase. Care should be exercised to see that ventilators are not directed into the crankcase for the same reason. Crankcase pressure release doors which are fitted to each main engine crankcase should be inspected periodically and the diaphragm, where fitted, renewed if damaged.

  • The following instructions regarding the prevention of explosions and fires in crankcases are to be prominently displayed on the engine and all E/Os are to be familiar with them:

    Holding Down Bolts Inspections
  • The tightness of holding down bolts, particularly of main and auxiliary engines must be checked every three months.
  •  At the time they are examined the chocks should also be tested to ascertain that no movement or fretting has taken place. 
  • Special precautions are to be exercised when checking holding down bolts with resilient pads to ensure that the alignment is not distorted. It is also necessary to check these parts if the vessel has been in heavy weather.

  • Labels:

    Hull efficiency

    Hull Efficiency is defined as the ratio of the effective power for a hull with appendages to the thrust power developed by propellers.

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    Cavitation of propellor and cavitation number

    Pressure distribution in a blade element is shown below

    As the pressure on the back of a propeller falls lower and lower with the increase in a propeller’s n, the absolute pressure at the back of the propeller will eventually become low enough for the water to vaporize and local cavities form. This phenomenon is known as cavitation. (     , vapor pressure of water

     Cavitation on a propeller

    • Lower the thrust of the propeller, & thus decrease its efficiency
    • Cause vibration of hull & the propeller and generate uncomfortable noise, &cause erosion of the propeller blade.

    Cavitation number 

    The cavitation is most likely to occur at the tips of blades where the relative velocity is the largest and the hydro-static pressure is the lowest when blades rotate to the highest position. 
    It can also occur near the roots where blades join the boss of a propeller because the attack angle is the largest.

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    “Quasi-propulsion” coefficient

    Quasi-propulsion” coefficient  defined as the ratio of the effective horsepower to the delivery horsepower.
     The division of the quasi-propulsive coefficient are
    1) understanding the propulsive problem 
    2) in making estimates of propulsive efficiency for design purposes.

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    Deck fire extinguishing system

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    Slot welding

    • A weld between two members, one containing an elongated hole through which the other member is exposed
    • The hole is completely or partially filled with weld metal, thereby joining the two members; one end of the hole may be open

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    Parts Of A Compressor Suction And Discharge Valve .Overhaul procedure

    1. Loosen The Castle Nut By Suitable Spanner.
    2. Take Out The Split Pin.
    3. Remove The Nut Washer.
    4. Remove Buffer Plate.
    5. Remove 3 Spring Plates.
    6. Remove Damper Plate.
    7. Remove Valve Plate And Guide Washer.
    8. Remove Locating Pin(it Keeps The Valve Aligned ).Now All The Plates Are Checked For Proper Seating , If Valve Plate Does'nt Seat Properly, It Is Lapped By A coarser And finer Paste, Making A Figure Of 8 On A True Surface Plate. A Figure Of 8 Is Made Because An Even And Continuous Lapping Can Be Done Only By A Figure Of 8.

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    Main Air Compressor ( safeties, unloader, bumping clearances )

    Discharge Unloader And  Its Operatiom

    •  One Of The Most Important Component, An Unloader Is Used For Unloaded Starting Of Compressor And Draining At Continuous Intervals. 
    • An Unloader Is Fitted At The End Of Drain Line From Inter And Aftercooler. It Is Basically A Solenoid Operated Spring Loaded Valve Arrangement. 
    • Unloader Has Two Lines Drain From Above And Delivery Air Pressure Of 1st Stage From Below. When Compressor Is Shut And Delivery Air Pressure Is Zero, The Drain Opens The Unloader Valve Against Spring Pressure, Thus It Is Always Open. When Started, Slowly The Delivery Pressure Rises And Tries To Shut
    •  The Valve, During This Time The Actuated Solenoid Valve Overcomes The Air Pressure And Keeps The Valve Open. 
    • The Solenoid Valve Is Operated By A Time Delay Circuit As The Time Span Of 10-15 Sec Gets Over The Solenoid Is Deactivated And The Unloader Valve Shuts. 
    • After Every 20-30 Mins., It Is Activated Again And Clears The Drain For 10-15 Secs, Then Deactivates. If The Unloaderdoes'nt Function Properly, There Is A Manually Operated Valve Just Before Unloader, Which Should Bebe Open Before Starting The Unloader.
    • Now, Why Is It So Important To Start The Compressor In Unloaded Condition?
      It Must Be Unloaded Because When Started The Compressor Draws A Very High Current, If It Will Be Loaded I.e Valve Not Open. The Motor Which Is Driving The Machine May Get Overloaded

    Safeties In A Reciprocating Compressor

    1. Lubricating Oil Pressure Low Cut Out: It Is Provided Such That If Lub Oil Pressure Falls Down The Parts Which Are Lubricated Like Liner, Piston, Main Bearings, Bottom End Bearings Might Get Worn Out.

    2. Bursting DiscIt Is Given In Intercooler And Aftercooler In The Water Side So That If Any Highly Pressurized Air Tube Bursts, The Cooler Shell Will Not Be Pressurized , Bursting Disc Will Burst And Liberate All The Water , Indicating Air-tube Burst. Generally Made Of Copper.

    3. Non- Return Valve In Delivery Line:
     It Is Provided, So That The Air Once Delivered Does'nt Return Back To The Compressor In Case A Low Pressure Develops In Compressor Side.

    4. Discharge Unloader: Already Explained Above.

    5. Relief Valve On Intercooler:
     A Relief Valve With Setting 10% Above The 1st Stage Pressure Is Provided To Release Air If High Pressure Is Generated In 1st Stage Generally Due To Valve Malfunction.

    6. Fusible Plug:
     Generally Made Of Tin, Antimony And Bismuth, Is Fitted In Inter And Aftercooler To Release Excess Air When Temperature Rises Upto 121 Degree Celcius Due To Rise In Pressure.

    7. High Temperature Alarm: At Around 90 Degree Celcius, The Alarm Sounds Denoting The Rise In Air Temperature.


    Multistaging In Compressor .why
    Multi-staging Is Conducting The Process Of Compression In More Than One Stagesi.e Air Is Compressed By Two Or More Pistons Before Delivery. Generally, Two Stage Reciprocating Compressors Are Used On Board. The Purpose Of Multistatgingis :-


    1.If We Increase The Pressure Of Air Upto 30bar (pressure Of Air At 2nd Stage) In One Stage, The L.o Will Start Burning Due To Rise In Temperature. As Per The Thermodynamic Equation For A Polytropic Process,
    T2/T1= (P2/P1)^(n-1/n )
    Where N=1.35 For Air.
    P2/P1= 30/1
    T2= 450 Degcelcius.
    At This Temperature L.o Will Burn As Flash Point Of L.o Is 200 Deg. Celcius. So We Keep The Pressure Ratio Limited To 5:1.

    2. To Reduce The Work Done By Compressor In The Whole Process. The Compression Of Air To Higher Pressure And Lesser Volume Is A Reversible Adiabatic Process. I.e Change In Temperature Takes Place, If Change In Temperature Is Kept Minimum Or Zero , The Work Done By Compressor Will Be Minimum.

    Bumping Clearance In Compressor And Measurement

     Bumping Clearance As The Name Signifies Is A Clearance Given So That The Piston Of The Marine Reciprocating Compressor Would Not Bump Into Its Cylinder Head.

    How To Check Bumping Clearance:-
    1. In Case A Suitable Opening Is Available The Piston Can Be Barred To The Top Dead Centre And Then Feeler Gauge Can Be Put Inside And The Clearances Checked At Two Three Points.

    2. The More Convenient Method Is To Take Lead Wire From The Engine Store And Make A Small Ball Based On The Expected Clearance And Put It Between The Piston And The Head From The Valve Opening. Then The Piston Is Slowly Turned To The Top Dead Centre With The Help Of A Tommy Bar. After That The Piston Is Again Turned Down And The Lead Wire Ball Is Extracted And The Thickness Measured With The Help Of A Micrometer. This Measurement Would Give The Bumping Clearance. The Caution Which Must Be Observed In These Methods Is That The Clearances Of The Main And The Crank Pin Bearing Have Not Been Taken Into Account. The Correct Method Is Thus That After Turning The Piston To Top Deadcentre The Piston Connecting Rod Must Be Jacked Up With The Help Of A Crow Bar. It Is Only After This Hidden Clearance Has Been Accounted For, Will The Correct Bumping Clearance Be Found.

    How To Adjust The Bumping Clearance

    • The Cylinder Head Gaskets Can Be Changed To A Different Thickness Thus Altering The Bumping Clearance.
    • The Shims Between The Foot Of The Connecting Rod And The Bottom End Bearing Can Be Changed Thus Changing The Bumping Clearance. However After Adjusting The Bumping Clearance The Clearance Should Be Checked Once Again To Make Sure That There Is No Error And The Clearance Is Within The Range As Specified By The Manufacturers.

    Change In Bumping Clearance
    • Wear At The Crankpin Bearing. The Crankpin Bearing Wears Down Due To Use And This Clearance Can Travel Right Up To The Piston And An Unloaded Piston Can Hit The Cylinder Head. This Type Of Wear Can Be Recognized When The Compressor Makes Impact Sounds Running Unloaded At The Starting And Stopping Operations. This Type Of Wear Would Also Be Accompanied By A Slow Decrease In Oil Pressure Over A Period Of Time.
    • Opening Up Of Cylinder Heads. In Certain Types Of Reciprocating Compressors The Cylinder Head Have To Beremoved For The Changing Of The First Stage Suction And Discharge Valves. When The Cylinder Head Is Put Back Thecorrect Thickness Of The Cylinder Head Gaskets Should Be Used Otherwise It Would Change The Bumping Clearance.
    • Wear On The Main Bearings. Over All Wear On The Main Bearings Would Lower The Crank Shaft And Would Thus Lower The Piston And Increase The Bumping Clearances.

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    Firing order of IC engine

    The order in which the ignition take place in various cylinders of a multi cylinder engine is called firing order. Every engine cylinder must fire once in every cycle. Three factors must be considered before deciding the firing order in IC engine. These are

    Engine Vibrations:

     Load on the bearing should not be imbalanced due to firing order of cylinder so firing order should be kept in such an order that the load is equally distributed on bearings. The imbalance load on the two bearings would result in severe engine vibrations.

    Engine cooling

    The firing should be in such an order that the cooling system should work in an effective manner. The cooling position should not change its position with time otherwise the task of the cooling system becomes very difficult.

    Development of back pressure

    There should be sufficient time and space for the exhaust gases to travel in the exhaust pipe otherwise the danger of back flow will rise.
    The commonly used firing orders for engines are:
    Three cylinder inline engine: 1-3-2
    Four cylinder inline engine: 1-2-4-3, 1-3-4-2
    Six cylinder inline engine: 1-5-3-6-2-4, 1-5-4-6-2-3, 1-2-4-6-5-3, 1-2-3-6-5-4.

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    List of certificates and documents carried onboard

    Certificates:

    1. Certificate of Registry
    2. International Tonnage Certificate
    3. International Load Line Certificate
    4. International Load Line Exemption Certificate
    5. International Ship Security Certificate
    6. Intact Stability Certificate
    7. Minimum Safe Manning Document
    8. Certificates For Masters Officers Or Rating
    9. International Oil Pollution Certificate
    10. Document Of Compliance
    11. Safety Management Certificate
    12. Damage Control Booklets
    13. Oil Record Book
    14. Garbage Record Book
    15. Cargo Securing Manual

    List of additional certificate for PASSENGER SHIP

    1. Passenger Safety Certificate
    2. Exemption Certificate
    3. Special Trade Passenger Ships
    4. Special Trade Passenger Ships Space Certificate
    5. Search And Rescue Co-Operation Plan
    6. List Of Operational Limitations
    7. Decision Support System For Masters

    List of additional certificate  for CARGO SHIP

    1. Cargo Ship Construction Certificate
    2. Cargo Ship Safety Equipment Certificate
    3. Cargo Ship Safety Radio Certificate
    4. Cargo Ship Safety Certificate
    5. Exemption Certificate
    6. Document Of Compliance With The Special Requirements For Ships Carrying Dangerous Goods
    7. Dangerous Goods Manifest Or Stowage Plan
    8. Document Of Authorization For The Carriage Of Grain
    9. Certificate Of Insurance Or Other Financial Security In Respect Of Civil Liability For Oil Pollution Damage
    10. Enhanced Safety Report File
    11. Record Of Oil Discharge Monitoring And Control System For The Last Ballast Voyage
    12. Bulk Carrier Booklet

    List of additional certificate   for NOXIOUS LIQUID CHEMICAL

    1. International Pollution Prevention Certificate For The Carriage Of Noxious Liquid Substances In Bulk
    2. Cargo Record Book
    3. Procedures And Arrangement Manual
    4. Shipboard Marine Pollution Emergency Plan For Noxious Substances

    List of additional certificate for CHEMICAL TANKER

    1. International Certificate Of Fitness For The Carriage Of Dangerous Chemical In Bulk.

    List of  additional certificate for GAS CARRIER 

    1. International Certificate Of Fitness For The Carriage Of Liquefied Gases In Bulk

    List of additional certificate for HIGH SPEED CRAFT

    1. High Speed Craft Safety Certificate
    2. Permit To Operate High Speed Craft

    List of Plans

    1. General Arrangement Plan
    2. LSA Plan
    3. FFA Plan
    4. Shipboard Oil Pollution Emergency Plan
    5. Garbage Management Plan
    6. Antenna Rigging Plan
    7. Shore Based Maintenance Plan
    8. Capacity Plan
    9. Shell Expansion Plan
    10. Ship Security Plan
    11. Ballast Water Management Plan

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    International safety managment (ISM ) code

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    seafarer identity document

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    Thursday, January 9, 2020

    SOLAS requirement for low and high expansion foam system

    SOLAS requirement of Low Expansion foam firefighting system

    • Foam system should be approved by the administration
    • Foam monitors should have the capacity to discharge 3litres/m2/minute.
    • The system should contain five times the volume the of largest space
    • Expansion ratio should not exceed 1000:1
    • The main control station should be located away from the cargo area, adjacent to accommodation space.
    • The system shall be capable to discharge foam, in no more than 5 minutes, the quantity should be sufficient to form a foam blanket over the largest single area over which oil fuel is liable to spread.
    • The system shall be capable to supply foam not less than 20 minutes on tanker fitted with inert gas system and not less than 30 minutes on tankers not fitted with the inert gas system.
    • The rate of supply of foam shall not be less than the greatest of following
      1. 0.6 l/min per square meter of cargo tanks deck area, where cargo tanks deck area means the maximum breadth of the ship multiplied by the total longitudinal extent of the cargo tank spaces
      2. l/min per square meter of the horizontal sectional area of the single tank having the largest such area; or
      3.  3 l/min per square meter of the area protected by the largest monitor, such area being entirely forward of the monitor, but in no case should the output of any monitor be less than 1,250 l/min.
    • The capacity of an applicator shall not be less than 400l/minute and should capable of through foam not less than 15 meters in still air condition.

    SOLAS regulation for High Expansion Foam

    • The system shall be approved by the administration.
    • The system shall be capable of manual activation and shall be designed to produce foam at the required rate within 1 minute of release. Automatic activation is not permitted unless appropriate interlocks are provided.
    • The system and control station shall be located away from protected space.
    • The quantity of foam concentration shall be sufficient to produce the foam volume equal to at least five times the volume of largest protected space(E/R), at the nominal expansion ratio, or enough for 30 minutes of full operation for the largest protected space, whichever is greater.
    • The system should be capable of rapid discharging foam @ at least 1 meter in depth per minute
    • The operating instruction for the system shall be displayed at main as well as local control stations.
    • If an IC engine is used as a prime mover for seawater pump for the system then the fuel tank of that engine shall contain sufficient fuel to run the pump on full load for at least 3 hours and reserves of fuel shall be available outside the machinery space of category A to enable to run the pump on full load for additional 15 hours.
    • The foam generators shall be located at the place where adequate fresh air supply can be arranged.
    • The arrangement shall be provided for the crew to safely check the quantity of foam concentration.
    • The arrangement of foam generators and piping of the foam system in the protected space shall not interfere with the access to the installed machinery for routine maintenance activities.
    • The system shall be supplied main as well as the emergency source of power.
    • The foam generator room shall be ventilated to protect against overpressure, and shall be heated to avoid the freezing

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    Why we use low expansion foam on deck and high expansion foam in the engine room?

    • Low expansion foam is having a more weight to volume ratio as compared to high expansion foam. 
    • If we use high expansion on deck, then wind effect will blow away the foam.
    •  The low expansion foam having sufficient weight to counter the wind force effect. So, it is easier for low expansion foam to form a blanket over fire properly.
    • In the engine room, wind effect is not present only we need to suppress the flammable gases and to give a cooling effect in the large volume of the engine room. So high expansion foam is good to cover more space in a short time

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    Main Engine Fuel oil system

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    Fresh water generator

    Starting
    • First, check if the engine speed is running above 50 RPM. The reason for this is that at low RPM the temperature of jacket water is around 60 degrees, which is not sufficient for evaporation of water
    • Check if the drain valve present at the bottom of the generator is in closed position
    • Now open the suction and discharge valves of the sea water or ejector pump, which will provide water for evaporation, cooling, and to the eductor for creating vacuum
    • Open the sea water discharge valve from where the water is sent back to the sea after circulating inside the fresh water generator
    • Close the vacuum valve situated on top of the generator
    • Now start the sea water pump and check the pressure of the pump. The pressure is generally 3-4 bars
    • Wait for the vacuum to build up. Vacuum should be at least 90% which can be seen on the gauge present on the generator. Generally the time taken for vacuum generation is about 10 minutes
    • When vacuum is achieved, open the valve for feed water treatment. This is to prevent scale formation inside the plates
    • Now open the jacket water inlet and outlet valves slowly to about half. Simultaneously close the bypass valve
    • Keep an eye on the jacket water pump pressure as it should not fluctuate. Always open the outlet valve first and then the inlet valve
    • Slowly start to increase the opening of the valves to “full” open
    • The boiling temperature would then start increasing and the vacuum would start dropping
    • The vacuum drop of about 85% indicates that evaporation has started
    • Open the valve from the fresh water pump to drain
    • Switch on the Salinometerif it has to be started manually. Generally it is on auto start
    • Now start the fresh water pump and taste the water coming out of the drain
    • When the fresh water starts producing, the boiling temperature again drops slightly and the vacuum comes back to the normal value
    • Check the saltiness of the water coming out of the salinometer. Also check the reading of the salinometer
    • This is done to see if the salinometeris working properly or not and to prevent the generated fresh water from getting contaminated with the salt water. The value of salinometeris kept below 10ppm
    • The freshwater pump pressure is normally between 1.2 and 1.60 bars
    • After checking the taste of the water coming out of the salinometer, open the valve for the tank from the pump and close the drain valve.
    Stopping
    • Stop the hot water supply to the plant.
    • Close valve for feed water treatment, if any
    • Stop freshwater distillate pump
    • Switch off the Salinometer
    • Stop the ejector pump and open air screw / air vent
    • Close valves on the suction and discharge side of the ejector pump
    • Close overboard valve for combined brine/air ejector
    • Close the valve to freshwater tank
    Operation of FWG steam injection system:

    If the heating of JCW is not sufficient for boiling water in FWG, addition steam heating through a system known as steam injection system.
    The steam injection system is a closed water/steam system where the steam is injected into a closed water circuit and condensation of steam heats the water which circulates in the evaporator.
    Procedure
    • Set the fresh water generator system as required for starting
    • Fully open the HT fresh water system evaporator by-pass and close the inlet and outlet valves of HT fresh water to evaporator
    • Open steam heating valve and steam heating fresh water priming valves
    • Close the priming valve once the fresh water is filled
    • Open steam supply valve to steam injector
    • Open the fresh water heating to the evaporator
    • Control the steam supply to control the rate of evaporation
    Parts of Fresh water generator:

    1 ) Heat Exchanger

    A heat exchanger allows for the heat to move from high temperature medium towards the low temperature medium; without actual contact in between. In the process a medium loose heat while the other gained it. A heat exchanger basically consists of a number of segregated elements; in form of plates or tubes with high thermal conductivity

    2 ) Demister

    A demister is a thickened layer of mesh structure; fitted in between the evaporator and the condenser element. This is used to separate sea water from the steam vapour. A demister can be made of nickel, monel metals, copper, stainless steel and synthetic fibers; such as Polypropylene and PVC. Typically; demisters made of monel metal are used for fresh water generator.

    3 ) Ejector Pump

    Both Brine and air ejector in combined are called as ejector pump in general. In maritime industry specially with marine engineers; the sea water pump supplying operating water to these ejector are many a times also considered in ejector pump. An ejector is similar to that of eductors with no moving parts.

    4 ) Distillate Pump

    A distillate pump is a normal centrifugal pump located at the lower most part of the fresh water generator. It takes suction from the steam condensate; and discharge to the drinking water tank on ship. The output pass through a salinometer which checks for the salt content in the output water.

    5 ) Salinometer

    A salinometer is the device installed on fresh water generator; capable of detecting even the slightest of salt content in the sampling water. It is connected to the distillate output just before the solenoid operated three way valve. The salinometer output is feed to the control panel; which then based on required salt limit will send fresh water for storage or back to generator.

    6 ) Sea Water Pump

    Since the both ejectors works on the principle of venturi effect; you need something to provide them with the operating water. This is where the sea water pump came into play; it not only pass through the ejector creating suction pressure but also provide feed water for the fresh water generator to produce steam

    7 ) Control Panel

    A control panel is what that makes it easier and possible to control and operate any machinery including fresh water generator. It is what that automate the starting and stop procedures; letting us just to monitor and see if its all well. It just makes it easier for us to start, stop, test alarms, test salinometer and set desired ppm level.

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    Cargo operated pump turbine (COPT)

    Cargo operated pump turbine (COPT) is required on tanker ships for discharging of loaded cargo to the port.
    COPT is steam driven centrifugal pump operated by steam produced from the ship’s boiler.
    STARTING
    • Check the lube oil sump level
    • Start the lube oil priming pump and check the pressure
    • Operate the vacuum condenser seawater pump suction and discharge valves to obtain a flow through the condenser
    • Switch on the breaker for vacuum condenser pump
    • Start the pump and check sea water pressure
    • Open the lube oil cooler seawater valves
    • Check the level for vacuum pump water supply
    • Check the water level in the condenser
    • Operate drain valve of turbine casing and remove the water
    • Operate the steam inlet and exhaust valves opening gland
    • Steam valve to provide sufficient steam pressure to the gland
    • Start the vacuum pump and check the vacuum pressure
    • Operate the condensate pump suction and discharge valves and then start the pump
    • Press the turbine rolling button and start warming up the COPT and check all the parameters
    • Check if the steam drain valve is open
    • After warming up, turbine will be ready to start
    • Check auxiliary boiler steam pressure when COPT is in operation
    STOPPING
    • Reduce the boiler load as per the consumption of steam
    • When the COPT is stopped, steam consumption is reduced, so adjust the load on boiler accordingly
    • After stopping the stripping pump, put the boiler on minimum firing load
    • Shut the steam inlet valve to stripping pump
    • Reduce the dump valve setting so that the steam pressure can be reduced
    • Stop the boiler and changeover to 6-9 bar mode
    • Shut the main dumping valve by putting the setting to zero
    • Shut the main steam valve for the COPTs
    • Shut the gland steam valves and air ejector steam inlet and outlet valves
    • Put the vacuum condenser condensate pump in manual and stop it, and shut the inlet and outlet valves of the condensate pump
    • Open the drains of all the COPTs, and drain the water. Close the drains after draining the water
    • Let the vacuum condenser cooling sea water pump running for 1 hour for cooling
    • Stop the vacuum condenser cooling sea water pump after 1 hour and shut the inlet and outlet valves of the pump
    • Stop the lube oil priming pump
    Preparing COPT for Cargo Operation
    • Change the boiler to high firing mode
    • Start the COPT as discussed above
    • Ensure to adjust the gland steam pressure and maintain it in between 0.3 –0.5 KG/cm2
    • Ensure COPT condenser vacuum is at correct pressure
    • Blow off the manual drain line for COPT steam line and governor drains
    • Open manual inlet valve for selected IG blower
    • Open measuring line from the selected blower to the O2 analyzer and ensure other lines are kept shut
    • Ensure the four position cock on the analyzer control panel is on the sample side
    • Start the IG system
    • IG mode must be selected at least 20 minutes before the cargo discharge operation
    • Ensure boiler ramps up to 40% load and O2 analyzer reading for the gas delivered in below 5%
    • Confirm with chief officer that transfer of COPT control to duty deck officer can be done
    • Transfer the COPT controls from remote to local i.e. to cargo control room

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    Quick closing valve

    A quick closing valve is an important part of the engine room fire fighting system. During emergencies, it cuts off one of the main sources of fire prominently present in the engine room - fuel oil.


    The quick closing valves are installed in all fuel tanks in the engine room. They can be closed from a remote position outside the engine room, normally from fire control station. These valves are spring loaded and are normally operated by following methods:
    • Wire-pulley system
    • Pneumatic system
    • Hydraulic system
    Wire pulley system operation:
    • Check for any slackness in the wire
    • Ensure all the wires are seated on the pulley
    • From the remote station, first release the required lever from its seat
    • Pull the lever with a jerk to operate the required quick closing valve
    • Once the quick closing valve is operated, the wire will be slackened
    Pneumatic system operation:

    A pneumatic cylinder with piston is fitted in the quick closing valve housing which operates the spring to close the valve. The normal working air pressure required is 7 kg/cm2 supplied from an air tank fitted in the fire station. This system covers all the oil tanks in the engine room.
    A separate bank of quick closing valves, which includes main engine and generator engines fuel oil supply lines, is operated by a different local station fitted near the 2nd deck of the engine room or near the main starting air receiver. The air for operation of these valves is provided normally by the control air system.


    Operating Procedure:
    • Check the air tank in fire station is full
    • Ensure the inlet valve of the tank is always open
    • For operating the engine room fuel tank valve, go to the fire station
    • To shut a group quick closing valve for tank system, operate/ push/ open the air valve for that quick closing valve
    • This will supply the air to the piston instead of venting which closes the quick closing valve
    • Emergency generator valve tanks are not included in the pneumatic system and a local wire pulley system is installed outside the emergency generator.
    The system is similar to pneumatic system with the operating media as oil.
    Operating Procedure
    • Check the hydraulic tank for oil level
    • Ensure there is no leakages from any hydraulic piping
    • For operating the engine room fuel tank valve, go to the fire station
    • To shut a quick closing valve for tank system, operate/ push/ open the hydraulic valve for that quick closing valve
    • This will supply the oil to the piston which closes the quick closing valve
    • Emergency generator valve tanks are not covered and a local wire pulley system is installed outside the emergency generator

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    Flooding in engineroom

    Engine room flooding as the name indicates, means filling up of the engine room space with water. Engine room flooding can affect the watertight integrity of ship.
    Action to be taken During Flooding

    • Call for maximum manpower to tackle the situation
    • The sooner you find the fault the better
    • Start the other circulating system and isolate the leaking pump, pipe, cooler etc.
    • Close inlet and outlet valves of the affected system to stop the leak
    • Inform chief engineer regarding the leak and follow the instructions from him
    • Put a notice or placard regarding leaking equipment or system and trip the breaker until repairs have been done
    • In case of any tank leakage, start transferring the excess content from that tank to any other tank and try to minimize it as much as possible
    • Tank should not be used until cement box or welding has taken place or repairs have been done
    2) In case of leakage from Overboard Valve
    • If the leakage is after the valve and if the valve is holding, shut the valve if the system involved for that valve permits normal operation of the ship with the valve closed
    • If the valve is not holding then identify the leak. It may be from the valve stem gland or flange joint; try to repair the leak
    • If system for that valve can be isolated without disturbing the normal operation of the ship, put a blank in the valve
    • If the repair is temporary then when ship reaches the port, call clivers to blank the valve opening from outside and carry out permanent repair
    3) Flooding due to crack in the hull or small hole
    • In this case, as soon as you find the leak, call for help from nearest coastal state because if the leakage is more, the ship's stability will be affected
    • By all means, the leakage has to be minimized and finally stopped
    • If the leak is not big enough, then cement box is to be put in place of the leak and repairs are to be done accordingly
    • In case of leakage due to damage from any accident like collision or grounding, there is nothing much that can be done as the opening in the bulkhead is large and there is no chance of stopping the leak. In such cases, the captain has to decide whether the ship is a safe place to stay or not and decision for abandoning the ship has to be made
    • In case of abandon ship signal announcement, the crew should muster to respective lifeboat and abandon ship operation should be carried out
    • For any of the above reasons, if the water level ingress in the engine room is very high, open the emergency bilge ejector valve with consent of the chief engineer and pump out the water overboard. Entry of the same is to be made in Oil record book (ORB) with date, time, and position of the ship and reason of direct discharge with signature of officer involved in operation, chief engineer, and master

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    Boiler fire


    There are three main stages of boiler fire:
    Stage 1: Normal Soot fire
    Stage 2: Hydrogen fire
    Stage 3: Iron fire

    Stage 1- Normal soot fire:
    Soot is deposited in the water tube of the exhaust boiler. When the ship is at slow speed, the exhaust temperature of main engine may vary from 100 to 200 °C . This temperature is enough to ignite “wet soot” whose ignition temperature is around 150 °C .
    If the soot is “dry”, it will not get ignited at such low temperature (150 °C) but when the engine is running at higher speed and the temperature of gases reaches to above 300 °C , then in the presence of excess oxygen the deposits of combustible materials will liberate sufficient vapor which can be ignited by a spark or a flame.
    The above type soot fire is called small or normal soot fire because the heat energy is conducted away by the circulating boiler water and steam. Also the sparks remain inside the funnel or diminish while passing through the flame arrestor in the funnel top.

    Stage 2: Hydrogen fire
    Hydrogen fire in an EGB occurs when the chemical reaction of dissociation of water takes place at temperature above 1000 °C. This leads to formation of Hydrogen (H2) and Carbon mono-oxide (CO) which are both combustible in nature.
    2H2O= 2H2 + O2
    (Dissociation of water leading to formation of hydrogen H2)
    H 2 O + C =H 2 + C O
    (Reaction of water with carbon deposits leads to formation of carbon monoxide-CO)

    Stage 3: Iron fire
    At this stage, the chain reaction of oxidation of iron metal starts at a high temperature of 1100 °C. This means at such high temperature the tube will start burning itself, leading to complete meltdown of tube stacks.
    2Fe + O2 = 2FeO+ heat

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    Boiler furnace blowback

    Cause of Boiler furnace Blow Back

    Main cause of boiler furnace blow back is accumulation of hydrocarbons inside the furnace. Hydrocarbons may exist as vapours or liquid form inside the boiler furnace. Accumulated fuel vapours inside furnace catches fire and develops high pressure inside the furnace thereby resulting in dangerous explosion. It is a usual practice that when there is frequent flame failure, operator try to fire the boiler in manual mode. In manual mode pre purging is not automatically controlled. Hence an attempt is made to fire boiler with insufficient pre purging time and eventuality may be catastrophic explosion.

    Preventive Actions

    • Allow sufficient time for pre purging the furnace with dampers full open to ensure all the accumulated vapours are expelled out.
    • Purging to be carried out 5-6 times the furnace volume for effective expelling.
    • Never try to reduce purging time or bypass it.
    • Carry out boiler burner and swirler routine as per planned maintenance system.
    • Do not fire boiler with heavy fuel oil or sludge if it is not designed for the same.
    • Air fuel ratio of oil compound regulator to be adjusted correctly to maintain proper and complete combustion.
    • Pilot burner to be maintained in good condition so that flame failure while starting does not occur.
    • Igniter or ignition transformer, its leads, etc. to be properly insulated and tightened.
    • Fuel oil fed to the boiler to be properly treated as per manufacturer’s recommendations.
    • If an economizer or pre heater is fitted in the boiler exhaust, same to be water washed and inspected regularly to avoid back pressure of gases.
    • Conduct furnace inspections periodically to inspect conditions inside.
    • When a flame failure is experienced find and rectify the root cause. Do not try to fire again and again.

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    Corrosion and Erosion

    • Both corrosion and erosion happen due to certain external actions on a surface. Corrosion means the destruction of materials through chemical reactions whereas erosion means the carrying away of the topsoil from the surface of the earth.
    • Corrosion normally happens because of chemical reactions. Erosion occurs by chemical reactions and by certain forces of nature. 
    • Corrosion also means the loss of electrons from the metals when it comes in contact with the moisture and oxygen in the atmosphere. Erosion happens because of natural forces like water and wind. Other factors such as acid rain, salt effects and oxidation of materials are also known to cause erosion.
    • In terms of the process, corrosion is an electro chemical process whereas erosion is a physical process. The corrosion of metals is often referred to as rusting and it is evident in the material itself. Erosion is a natural process that removes or carries away materials from one place to another. 
    For instance, when sand is carried away from the beach or riverbanks, it is still sand even after erosion. Corrosion isn’t like that. When corrosion takes place, the material will be transformed to another chemical compound known as rust.
    • Various types of corrosion include galvanic, crevice, pitting, intergranular and selective leaching. Erosion also involves several different processes like weathering and dissolution. 
    • Both corrosion and erosion can be prevented. To prevent corrosion, a protective layer is coated on the surface of the metal that constantly comes in contact with the atmosphere. 
    • Terracing the terrain or planting more trees on the surfaces where erosion is likely to happen can prevent erosion

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    Hunting gear mechanism

    • The floating lever movement to the left pulls the pump control lever also to the left with the pivoting taking place at the bottom point. When the tiller arm turns it pushes the hunting link to the right, which in turn pushes the pump control lever inwards and to mid position with pivoting taking place at the top point.
    • At mid position the pump is at ‘no stroke’ and thus the rudder is stopped at that helm angle. For the rudder to be brought back to the midship position the telemotor receiver cylinder will have to move to the left, the floating lever top to the right pushing the pump control lever further in.
    • Pump will start and the tiller will move in the opposite direction, pulling the hunting link to the left. This will in turn, will pull out the control lever of the pump back to the mid position, pivoting about the top floating lever point.

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    VIT and Super VIT

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    Wednesday, January 8, 2020

    Inclining experiment

    Purpose

    Ship’s stability calculations not only rely on the ship’s geometry but also on the knowledge of where the ship’s centre of gravity (G) is positioned. Although the distance of G from the keel can be ascertained for various conditions that the ship may be in, it is essential that it is accurately known for one specified ship condition.
    To this end, the need to carry out an inclining experiment becomes necessary and from this, two facts should become known
    1. the displacement; and
    2. the position of G in a known ship’s condition.
    The inclining test is carried out to find the lightship KG at the lightship displacement. It is sometimes known as a ‘controlled list experiment’. By conducting the experiment by means of a series of weight shifts, the GM of the vessel can be ascertained under the test condition. This GM value can then be compared with the ship’s KM to obtain the vessel’s KG value: KM – GM = KG

    The environment of the dry dock is ideal for performing such a stability check. While the vessel is in the dock, it is usually in its light condition, the water is still and the facilities for moving known weights are readily on hand

    Conditions for Carrying Out the Inclining Experiment

    1. The vessel should be upright.
    2. The moorings should be slack, allowing the vessel to be inclined without restraint.
    3. The vessel should be in still water conditions.
    4. The density of the water should be known.
    5. There should be no free surface action inside the ship’s tanks.
    6. The contents and weights of all the ship’s compartments should be known.
    7. Calm weather conditions should prevail.
    8. The vessel should be clear of all unnecessary personnel.
    9. The light condition displacement should be known from the builders.
    10. The fore and aft draughts and the mean draught should be noted

    Experiment Preparations

    The ship in an upright position, in its light condition, is fitted with a wire plumb line suspended from a high point on the transverse centre line. The ‘plumb bob’ on the end of the line is set into a horizontal trough of light oil or other viscous substance to dampen the movement of the plumb bob, once the vessel is inclined. Fastened to the edge of the trough is a graduated scale batten, measured in millimetres.



    The inclining weights are then placed on board, preferably by the dockside cranes. These weights are usually fitted with a wheeled platform to assist movement on board the vessel, throughout the period of the experiment. Finally, all non-essential persons are sent ashore and the gangway is landed.

    Conduct of the Experiment

    The vessel is then caused to be listed over, by moving the weights of the ship’s centre line, to a measured, accurate distance in a horizontal direction.
    List Moments + Displacement = GG1 (namely the horizontal shift in the ship’s C of G)
    Unless the displacement value is known, it would be usual practice to carry out a draught survey prior to conducting the experiment in order to obtain the exact displacement figure.

    Graphic Presentation (vessel floating freely)

    1. Consider the two similar triangles ABC and GMG1
    2. In triangle ABC: AB represents the length of the plumb line.
    3. BC represents the deflection when the ship is heeled.
    4. In triangle GMG1: GM represents the ship’s metacentric height in this condition.
    5. GG1 is the shift of ‘G’ due to the moving weight.
    As the triangles are similar:
    Then Tan Ø = GG1 + GM but Tan Ø = BC ÷ AB
    Therefore: GM = GG1 × AB + BC
    But GG1 = (w × d ) ÷ Displacement
    Therefore: GM = (w × d × AB) ÷ (Displ. × BC)
    Where: w × d = list moments (in tonne metres)
    AB = Length of the plumb line (in metres)
    BC = Deflection of plumb line (in metres)
    Displ. (W) = Ship’s weight in this condition

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