Onboard Lubricating Oil Tests

(By Kamal Hossain, Chief Engineer)

(a) Explain how lubricating oil can be tested onboard.

Answer:

L.O can be tested on board by using Maker’s supplied test kit , which can give the result whether it is safe for further use or not.
For L.O test , sample oil must drawn out from correct point , such as from test cock or from pump’s discharge pressure gauge connection. It should not be drawn out from , filter out let and purifier out let .
Sample oil must be taken with standard plastic tube with seal for both on board test and Lab. analysis.
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Boiler Water Tests

(By Kamal Hossain, Chief Engineer)

Q. (a) Explain why regular testing of water in auxiliary boiler is advisable
(b) How to take correct sample
(c) Discuss what factors are necessary when measured value differ appreciably from desired value in each test.
(d) Give reasons for the situation when alkalinity is found to have fallen unaccountably.

Answer:

(a) For the well boiler operation, boiler water should be tested regularly and accurately. Then correct chemical treatment should be followed based on the test results for the following reasons.

– To keep the boiler water in alkaline condition
– To precipitate all scale forming , both dissolved and suspended salts in the boiler water , in the forms of removable and non-adherent sludge.
– To remove dissolved oxygen , carbon dioxide and other gases
– To produces substances which will be well below the limits for carry over , foaming and priming..
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Summary of Steering Gear Regulations & Requirements

(By Kamal Hossain, Chief Engineer)

SOLAS  REGULATION & REQUIREMENTS FOR STEERING GEAR

  1. Steering gear compartment must be separated from machinery spaces and readily assessable.
  2. Every ship shall be provided with main steering gear and auxiliary steering gear.
  3. The failure of one of them must not render the another one operation.
  4. Relief valves shall be fitted to any part of the hydraulic system. Setting shall not exceed designed pressure, i.e , 1.25 times of working pressure.
  1. Main steering gear and rudder stock shall be:
  • Capable to put rudder hard over from 35 deg. one side to 35 deg. another side not more than 28 second while running with full sea speed and full loaded draught.
  • They should be done at maximum astern speed as also.
  • Read more

UMS System Failure

(By Kamal Hossain, Chief Engineer)

It is complete failure of the UMS, bridge control and data logging system has failed and the main engine is needed to run on manual control and monitoring.
(a) State with reasons six main items of data, which require to be monitored and recorded manually.
(b) Explain how a watch keeping system should be arranged to provide for effective monitoring and control of the main engine.
(c) Explain how the staff will be organized to maneuver the engine safely. State the machinery plants at which attentions are required during maneuvering.

Answer:

(a) When M.E to be put on manual control and monitoring, the following six main items of data to be monitored and recorded manually.

1. Cooling water system.
It is required to prevent the thermal stress and thermal loading on the engine. Engine may breakdown in severe
Case.
– Jacket water temperature and pressure
– Piston cooling temperature and pressure ( If water cool )
– Sea water temperature and pressure ( For Coolers & condenser ) …. to be checked & recorded.
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Effects of Impurities in Fuel Oil

Q. Write brief notes on the adverse effects that a fuel containing high value of the following may cause: (a) Viscosity (b) Density (c) Sulphur (d) Corodson Carbon Residue (e) Asphaltene (f) Vanadium & Sodium (g) Ash (h) Water

(By Kamal Hossain, Chief Engineer)

Viscosity

High viscosity of fuel may cause the following effects being using high temperature heating
– Fouling of Oil heater
– Gassing of Fuel
– Thermal expansion to fuel pump and injector component leading to seizure or sticking
– Clogging of filter
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Boiler Water Treatment

By Maklub Al Mostofa

Scale formation and corrosion are the main two factors that determine the efficiency of the internal parts and as well as lifetime of the boiler. Badly corroded and scaled boiler can fail within very short time.

SCALE FORMATION IN BOILER

Depending upon the sources boiler water contains various types of salts and impurities. Under operating conditions all the salts comes out of the water. These salts cause formation of scale inside the boiler. The more the water contains solids and salts the more the boiler is prone to scale formation. Read more

Oil Record Book (Questions & Answers)

By Maklub Al Mostofa

QUESTIONS:

  • How to put entry in ORB?
  • What is action in case of wrong entry?
  • How many people fill up and sign it?
  • What is your action if an entry is missed?
  • What is your action if you make any mistake?

 ANSWER:                               

    • This guidance only includes sections C to I.
    • Operations should be recorded in chronological order as they have been executed on board.
    • Dates should be entered in dd/mm/yyyy format, e.g. 16-MAR-2009.
    • Incineration or landing ashore of oily garbage and used filters should be recorded in the Garbage Record Book only.
    • All Entries are to be made and signed by the officer or officers in charge of the operations concerned and each completed page shall be signed by the master of the ship.
    • Do not leave any full lines empty between successive entries.
    • Read more

CoC Oral Exam Questions Bank

By Maklub Al Mostofa

Maritime Regulations and Survey

    1. Describe Safety construction survey and items to be surveyed.
    2. Describe Load line survey. Purpose of load line survey. Why do we need load line certificate?
    3. Describe LOAD Line convention.
    4. Why load line mark is at the mid ship/ how to calculate load line for a ship?(details)
    5. Details about Safety equipment survey
    6. How many certificates to be carried on board?
    7. Describe Life boat regulation?
    8. Describe MLC 2006 details
    9. Describe Ballast water regulation.
    10. Describe SOLAS chapters and new amendment
    11. Describe MARPOL ,ALL THE ANNEX OF MARPOL,
    12. All the chapters of annex vi, details of NOx , SOx limit, tyre ,EEOI ,EEDI, SEEMP…….
    13. What is HSSC?
    14. ESP(Enhanced survey program)
    15. Regulation for vent pipe, sounding pipe
    16. Preparation for PSC inspection as C/E?

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Planning & Preparation of Dry Dock as a Chief Engineer

Image Credit:  www.rbrodarstvo.com

Preparations:

Dry docking survey is to be done every 2 ½ years interval , 2 times in 5 each year cycle , called annual docking and special docking survey. Special survey is carried out every 5 years interval.

As a Chief Engineer of a vessel , he must study the time of  dry docking due , verify annual or special , and  prepare documents & defect list to be repaired , at least 3 months priority for easy and efficient supports from ship company.

Preparation of Documents:

    • The necessary plans , drawings , instruction manuals , service records of previous docking to be collected and kept ready . Copy of plans and drawing to be sent to dockyard on request.
    • List and intend the followings to be supplied in time
    • Needful machinery spares repair materials for ship staff’s job
    • Paints
    • Collect and keep ready for special tools and devices
    • Issued needful instructions for safety , fire precaution and pollution prevention.
    • Issue assignments for the work to be done before entering dry dock and to be undertaken by E/R staffs under 2nd Engineer supervision.

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    CoC Oral Exam Preparation (Part – 20): OWS & Regulations

    MARPOL Regulations of Discharging Machinery Bilge into the sea:

    The rules and Regulations that govern the operation of an Oily Water Separator are under MARPOL  Annex I: “Prevention of pollution by oil”.

    Regulation 14: Oil Filtering Equipment

    1. Vessels above 400 GT and less than 1000 GT shall have an oil filtering equipment
    • Approved by the Administration
    • Will ensure that any oily mixture discharged into the sea after passing through the equipment has an oil content not exceeding 15 ppm

    2.  Vessels above 1000 GT shall have an oil filtering equipment

      • In addition to the above, shall be provided with alarm arrangements to indicate when the level cannot be maintained.
      • Also arrangements to ensure that any discharge of oily mixture is automatically stopped when the oil content of the effluent exceeds 15 ppm

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    CoC Oral Exam Preparation (Part – 19): Engine Room Watch Keeping

    Watch Keeping in Engine Room:

    pic05_up
    Image Credit: www.jamstec.go.jp

    A. Handing over a watch:

    Engineers on ships perform their duties in rotational shifts, each having fixed and equal number of hours. This work shift, also known as a watch, needs to be carried out in an efficient manner to ensure the safety of life and property at sea. The normal watch keeping schedule and responsible watch keeping engineers in a fully manned engine room:
    0800-1200——4/E,  2000-2400—-4/E
    1200-1600——3/E,  2400-0400—-3/E
    1600-2000——2/E,  0400-0800—-2/E

    1. A watch keeping engineer should take extra care while handing over the watch to the incoming watch keeping engineer to make sure that the ship runs safely and smoothly.
    2. It is  necessary that the right information is passed to the incoming engineer by the engineer on watch so that he can concentrate on his watch and perform more demanding and important jobs.
    3. Handing over of the watch should be carried out according to the instructions provided by the chief engineer’s standing orders and company’s instructional manual. It should be done very sincerely and honestly so that the watch keeping becomes smoother and continuation of any kind of work is not affected on the ship.
    4. The following things need to be informed to the reliving officer:
    5. Special orders related to any ship operation from bridge or the company
    6. Standing orders from the chief engineer
    7. Special mode of navigational operation of ship in case of emergency situation, damage, icy, or shallow water etc
    8. In case there is any kind of maintenance work being carried out in the engine room by other engineers and crew members then their work location, details of machinery under maintenance, and information of authorized person and crew members should be provided.

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    CoC Oral Exam Preparation (Part – 18): Electrical Miscellaneous

    16

    Servicing a motor effected/washed by seawater:

    1. Cut out power supply by circuit breaker & taking out fuse. Mark & disconnect supply wire. Took Megger reading & recorded.
    2. Take out the motor, open up & dismantle. (Make sure marking on both cover & body)
    3. Clean and wash with warm fresh water.( About 180′ F)
    4. Cover by canvas, dry with positive ventilation & 500 watt lamp
    5. Clean with Electro cleaner.
    6. Baking by 500 Watt lamp for few hours.
    7. Take Megger reading. (test stable or constant reading) Apply insulation varnish to the winding while warm.
    8. Baking & taking the Megger.
    9. Reassemble & put back into service.
    10. When test run check sound, ampere & temperature.

    Read more

    CoC Oral Exam Preparation (Part – 17): Boiler Safety Valve

    Boiler Safety Valves protect the boiler from over pressurisation. As per the requirements, at least two safety valves should be fitted to the boiler and both are mounted on a common manifold with a single connection to the boiler. Boiler with super heater, normally three safety valves are fitted; two to the boiler drum and one to the superheater. The superheater must be set to lift first to ensure a flow of steam through the superheater.

    Improved High Lift Boiler Safety Valve:

    1245

    Fig: Improved Highlift Boiler Safety Valve

    The sketch shown is improve high lift safety valve . The are usually mounted 2 Nos. on a single chest. Valve , seat , spindle , compression screw and bush are made of non-corroded metal and valve chest is made of cast steel.
    This valve improve than other type as because:

    • Using wingless valve to improve steam flow
    • Floating cylinder arrangement can prevent piston seizure.

    Read more

    CoC Oral Exam Preparation (Part – 16): CO2 Flooding System

     Requirements of CO2 Room:

    In CO2 flooding system, carbon dioxide bottles are placed in a separate room. The requirements for location, accessibility, use and ventilation of CO2 storage spaces as per IMO are:

    • Spaces for storage of cylinders or tanks for extinguishing gas should not be used for other purposes.
    • These spaces should not be located in front of the forward collision bulkhead.
    • Access to these spaces should be possible from the open deck.
    • Spaces situated below the deck should be directly accessible by a stairway or ladder from the open deck.
    • The space should be located no more than one deck below the open deck.
    • Spaces where entrance from the open deck is not provided or which are located below deck are to be fitted with mechanical ventilation.
    • The exhaust duct (suction) should be lead to the bottom of the space.
    • Such spaces should be ventilated with at least 6 air changes per hour.

    Read more

    CoC Oral Exam Preparation: (Part – 15): Fire & Safety

    Fire Hose:

    1. At least one fire hose for each of the hydrants and hose shall be used only for extinguishing fires and testing purposes. (Passenger Ship)
    2. One for each 30m length of ship and one spare, but not less than 5 in all. (Cargo Ship = or > 1000GT) and ship carrying dangerous goods shall be provided 3 hoses & nozzles in addition to those required above and cargo ship <1000GT, shall be provided no less than 3 fire hoses & nozzles.
    3. 2 ½” diameter and 30ft or 60ft. length.
    4. Nozzle for ER 12mm, 16mm and 19mm size and shall be approved for duel purpose (jet/spray) incorporating shut-off valve.
    5. Fire hoses shall have a length of at least 10 m, but not more than:
    • 15 m in machinery spaces;
    • 20 m in other spaces and open decks; and
    • 25 m for open decks on ships with a maximum breadth in excess of 30 m.

    Read more

    CoC Oral Exam Preparation (Part – 14): Ship’s Certificates

    Certificates onboard:

    1.Certificate of Registry
    2. International Tonnage Certificate
    3. International Load Line Certificate
    4. International Load Line Exemption Certificate
    5. Certificates for Master, Officers and Ratings
    6. Derating or Derating Exemption Certificate
    7. International Oil Pollution Prevention Certificate
    8. International Sewage Pollution Prevention Certificate
    9. International Safety Management Certificate, SMC
    10. International Medical Certificate
    11. Passenger Ship Safety Certificate
    12. Cargo Ship Safety Construction Certificate, SAFCON
    13. Cargo Ship Safety Equipment Certificate, SEC
    14. Cargo Ship Safety Radio Certificate
    15. Exemption Certificates for SAFCON, SEC and Radio Certificate
    16. Certificate of Classification
    17. Certificate of Insurance or other financial security in respect of civil liability for oil pollution damage
    Read more

    CoC Oral Exam Preparation (Part – 13): Entries of Important Documents

    OIL RECORD BOOK:

    Entries to be made in Oil Record Book as per MARPOL Annex I Requirements:

    Oil Record Book: PART – 1 (MARPOL Annex I Regulation 17): 

    Entries:

    1. Ballasting or Cleaning of fuel oil tanks
    2. Discharge of dirty ballast or cleaning water from fuel oil tanks
    3. Collection , Transfer and disposal of oil residues
    4. Non automatic starting of discharge overboard, transfer or disposal otherwise of bilge water accumulated in machinery spaces
    5. Automatic starting of discharge overboard, transfer or disposal otherwise of bilge water accumulated in machinery spaces
    6. Condition of the oil filtering equipment (Out of order or malfunction)
    7. Accidental or other exceptional discharges of oil
    8. Bunkering of all types of fuel oils or bulk lubricating oils
    9. Additional operational procedures and general remarks
    10. Recording of quantities retained in bilge water holding tanks (listed under section 3.3 of the IOPP Certificate) is voluntary.
    11. The recording of general maintenance of items pertaining to the OWS remains voluntary and is not required to be recorded in the ORB.

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    CoC Oral Exam Preparation (Part – 12): Stern Tube

    1245Image Credit: www.libramar.net

    Stern Tube:

    The stern tube is a hollow tube-like structure at the stern or rear part of the ship. A ship needs the propeller to drive it forward in water. The propeller, located outside the ship, needs to be connected to the engine inside the ship’s engine room. The propeller shaft is used for connecting the ship’s engine and the propeller. The stern tube is a narrow hole in the hull structure at the rear end (aft peak) of the ship, through which the propeller shaft passes and connects the engine and propeller.

    Stern tube bearings serve two main functions:
    1. To properly connect the propeller to the ship
    2. To keep water from leaking into the stern tube (and lubricant from leaking out)
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    CoC Oral Exam Preparation (Part- 11): Propulsion Machinery

    Marine-propulsion-systemImage Credit: Wikipedia.org

    FUEL INJECTION TIMING

    Checking of fuel injection pump timing:

    1. Turn 1 piston to TDC at the beginning of firing stroke.
    2. Turn backward to a point, a little earlier than fuel injection point.
    3. Shut fuel supply to engine, remove No. 1 fuel pump delivery valve assembly and put a bent pipe.
    4. Open fuel supply and when fuel lever is put to running position, oil will flow out at bent pipe.
    5. Turn engine towards TDC in its running direction slowly until fuel cease to flow.
    6. Check the marks on flywheel whether timing position is correct or not.

     Slight difference can be adjusted by:

    For large engine:

    •  Timing can be altered by shifting the camshaft to the position relative to crankshaft, after removing the idler gear between crankshaft and camshaft.
    • Timing can be altered by individual fuel pump cam for adjustable cam type engine.
    • Read more

    CoC Oral Exam Preparation (Part-10): Ship Construction

    Ship_size_(side_view)Image Credit: wikipedia.org

    Definitions and Ship’s Dimensions

    Hull:
    The structural body of a ship including shell plating, framing, decks and bulkheads.
     Afterbody :
    That portion of a ship’s hull abaft midships.
     Forebody:
    That portion of a ship’s hull forward midships.
     Bow :
    The forward of the ship
     Stern :
    The after end of the ship
    Port :
    The left side of the ship when looking forward
    Starboard :
    The right side of the ship when looking forward
    Amidships:
    point midway between the after and forward perpendiculars
    Read more

    CoC Oral Exam Preparation (Part – 9): Refrigeration & Air Conditioner

    header_refrigeration

    Image Credit: almaco.cc

    Refrigeration:

     What is a Refrigerant?

    • Refrigerants are used as working substances in a Refrigeration systems.
    • Fluids suitable for refrigeration purposes can be classified into primary and secondary refrigerants.
    • Primary refrigerants are those fluids, which are used directly as working fluids, for example in vapour compression and vapour absorption refrigeration systems.
    • These fluids provide refrigeration by undergoing a phase change process in the evaporator.
    • Secondary refrigerants are those liquids, which are used for transporting thermal energy from one location to other. Secondary refrigerants are also known under the name brines or antifreezes

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    CoC Oral Exam Preparation (Part – 8): Air Compressor

    Air Compressor

    H-274
    Image Credit: leelloyds.com

    Effects of leaking valves in Air Compressor:

    First Stage Suction:

    • Reduce air delivery
    • Reduce 2nd stage suction pressure
    • Unload the compressor
    • Increase running time.

    First Stage Delivery:

    1. Reduce air delivery
    2. Increase discharge temperature
    3. Less air drawn in, due to high-pressure air leaking back into cylinder.

    Read more

    Ventilation Arrangement for Hazardous Spaces in Engine Room

    The following engine room spaces are very hazardous on-board the ship and therefore, a special ventilation arrangement should be provided for safe entry:

    (a) CO2 storage compartment
    (b) Battery room
    (c) Purifier flat
    (d) Refrigerating machinery space
    (e) Shaft tunnel

    Ventilation Arrangement for Confined Spaces of Ships:

    (a) CO2 storage compartment
    – CO 2 compartment is situated on open deck , well ventilated and easily accessible .
    – Its compartment door is opened outward.
    – Boundaries between CO2 compartment should be watertight.
    – Ventilation louver is fitted at the bottom near the floor , for the leaky CO2 to release to atmosphere because CO2 is more heavier than normal air.
    – In some ships , exhaust fan is provided . Its suction is taken from bottom of the compartment and lead to open air deck . Exhaust system is separately provided from others.
    – In some modern built ships , CO2 leakage warning alarm is provided
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    CoC Oral Exam Preparation (Part-7) – Maritime Security

    isps1
    Image Credit: www.msecurity.ru

    When do the security measures come into force ?

    – 1st July, 2004.

    SOLAS amendments adopted in December 2002 :

    Chapter V:
    – Automated Identifications Systems(AIS)

    Chapter XI-1:
    -Ship identification number
    -Continuous Synopsis Record (CSR)

    Chapter XI-2:
    -Measures to enhance maritime security
    -International Ship and Port Facility Security (ISPS) Code (Parts A & B)
    Read more

    CoC Oral Exam Preparation (Part-6) – Boiler Operation & BW Treatment

    Boiler :

    Boiler Automatic Burning System:

    1. With correct water level, steam pressure transmitter initiates cut-in at about 1.0 bar below working pressure.
    2. Steam pressure transmitter initiates Master Relay to allow ‘Air On’ signal to force draught fan.
    3. Air feedback signal confirms ‘Air On’ and allows 30-sec. delay for purge period.
    4. Then Master Relay allows Electrode to strike ‘Arc’.
    5. Arc striking feedback signal confirms through electrode relay and allows 3-sec. delay.
    6. Then Master Relay allows burner solenoid valve for ‘Fuel On’ operation.
    7. Fuel On feedback signal allows 5-sec. delay to proceed.
    8. As soon as receiving Fuel On feedback signal, Master Relay checks ‘Photocell’, which is electrically balanced when light scatter continuously on it.
    9. Result is OK and cycle is completed.
    10. If not, fuel is shut-off, Alarm rings and cycle is repeated.
    11. Steam pressure transmitter initiates cut out automatically at about 1/15 bar above W.P.
    Read more

    CoC Oral Exam Preparation (Part- 5) – Boiler

    Exhaust Gas Boilers:

    • About 30% – 34% of Fuel Energy input to engine are discharged to Exhaust Gas, as Thermal Energy.
    • This thermal energy is converted into useful work in Exhaust Gas Boiler.

    Cochran Exhaust Gas Boiler:
    1. A double-pass, vertical type, in which Exhaust gases from ME pass through 2 banks of tube.
    2. Served as an efficient silencer, when the boiler is in use.
    3. A separate Silencer, always fitted along with exhaust gas boiler, to be used when the boiler is generating more steam than required.
    4. All or part of exhaust gases can be directed to the Silencer and atmosphere, without going through the boiler.
    5. Working Pressure is around 7 bars.

    Composite Boiler (Composite type Cochran boiler):

    1. If Exhaust Gases and Oil fire can be used at the same time, it is termed Composite Boiler.
    2. In double-pass, composite type Cochran Boiler, it provides a separate tube nest for exhaust gas passage, situated immediately above the return tube nest from Oil-fired Furnace.
    3. Exhaust gases from Oil-fired Furnace and ME; pass through the tubes, which are surrounded by boiler water.
    4. Separate Uptakes provided for Exhaust Gases and Oil-fired Smoke.
    5. Heavy Changeover Valves are fitted, to divert the gases straight to the funnel, when desired.
    Read more

    CoC Oral Exam Preparation (Part- 4) – Lub Oil & Fuel Oil

    MLT
    Image Credit: lube-oil.in

    Lubricating Oil

    Viscosity:
    1. A measure of internal resistance to flow.
    2. Viscosity of an oil changes with temperature, falling when temperature rises and vice versa.
    3. For crankcase oil, viscosity is between 130 – 240 Sec. Redwood No. 1 at 60°C.
    4. For cylinder oil, viscosity is 12.5 – 22 Cst.

    Viscosity Index, VI:
    1. The rate of change of viscosity of an oil, in relation to change of temperature.
    2. Oil of low VI has greater change of viscosity with change in temperature,
    than the oil of high VI.
    3. For crankcase oil, VI is between 75 – 85; For cylinder oil, VI is 85.
    4. Highest VI of mineral oils is about 115 and with special additives, this may be raised to about 160.
    5. Hydraulic oils, used in remote control hydraulic circuits must have very high VI; otherwise erratic response to the controls can be troublesome. (Telemotor hydraulic system oil has VI of 110.)
    Read more

    CoC Oral Exam Preparation (Part- 3) – Electrical

    images

    image credit: www.rchelectrical.co.uk

    Electrical Survey:

    Electrical equipment inspected and tested, during complete engine survey, at 4 years interval.
    Such a survey is prescribed, under the rules and regulations for the classification of ship.
    Following survey items generally apply to all ships:
    1. Generators and governors.
    2. Circuit breakers
    3. Switchboard and fittings (main and emergency switchboard, distributor switchboard).
    4. Cables
    5. Insulation resistance
    6. Motors and Starters
    7. Emergency power equipment
    8. Parts of steering gear
    9. Navigation light indicator
    Read more

    CoC Oral Exam Preparation (Part- 2) – Survey & Certification

    images (1)

    Image Credit: Marinelink

    Survey:

    Authorised independent examination, investigation, and inspection, measuring or testing of ship structure, machinery and equipment, done and supervised by Surveyors appointed by regulatory or commercial organisations.

    Classification Societies:
    They are third party independent bodies e.g. ABS (American Bureau of Shipping), BV (Bureau Veritas), LR (Lloyd’s Register), ClassNK (Nippon Kaiji Kyokai), DNV (Det Norske Veritas), GL (Germanischer Lloyd).

    Their functions:
    1. To ensure that ship is soundly constructed and the standard of construction is maintained.
    2. Carried out Statutory Survey on behalf of the Administration regarding the ship safety and prevention of pollution of marine environment.
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    CoC Oral Exam Preparation (Part- I) – Machinery

    MAN-B&W-K98MC-74760kw
    Source: MAN Diesel (MAN-B&W-K98MC)

    Cylinder liner wears:
    1) Normal frictional wear: Due to metal to metal contact with high surface asperities under
    marginal lubrication condition.
    2) Abrasive wear: Due to presence of hard foreign particles from fuel, LO, and air.
    3) Corrosive wear:Due to H₂SO₄ acid attack owing to sulphur within fuel. Only 0.1% of sulphur content causes corrosive wear, like hot and cold corrosion, and the rest carried away by exhaust gas. Sulphuric acid dew point = 120΄C to 160΄C.

    Hot corrosion occurs at 460 – 570΄C.
    Due to HCl acid attack, because of salts in air, charge air cooler leakage,
    sea water in fuel and LO.

    Other related causes:
    1. Unsuitable liner material.
    2. Incorrect ring clearance.
    3. Misalignment of piston and liner.
    4. Insufficient LO or improper arrangement of cylinder lubrication.
    5. Cylinder oil having too low viscosity or alkalinity.
    6. Cylinder oil containing abrasive particles.
    7. Using of low sulphur fuel, in conjunction with high TBN cylinder oil.
    8. Improper grade of fuel, and improper combustion.
    9. Improper running-in, without high cylinder oil feed rate.
    10. Overloading of engine.
    11. Too low scavenge air temperature, leading to dew point corrosion.
    Read more

    CoC Oral Exam Preparation (Part – 20): EKG

    1234 

    How does emergency alarm ring?

    Ans:    Continuous ringing of bell. Emergency situation is explained at the muster situation. Pattern of Emergency signal is indicated on Muster list

    Q. Explain the Fire Tube and Water Tube Boiler.

    Fire Tube Type: Due to simple design of the tubes effective heat transfer takes place, but periodical cleaning/maintenance is slightly difficult. Soot blowing is not effective for regular cleaning. Used with low pressure boiler

     Water Tube type: In comparison to fire tube type heat transfer is not so so effective. Gas side cleaning is easier, sometimes fixed water spray design is used for cleaning.  Soot blowing is effective , used with medium – high pressure boiler

    Q. What is Ogee ring?

    Ans:    Connects the bottom of the furnace to the boiler shell plating.
    Read more

    Question and Answer for Oral Exam, Part – 1

    What is I.S.M. ?

    The International Management Code for the Safe Operation of Ships and for Pollution Prevention (International Safety Management (ISM) Code).

     What is I.M.O. Convention ?

    Conventions are chief instruments of IMO, being binding legal instruments, regulating some aspect of maritime affairs of major concern to IMO e.g. safety of life at sea (SOLAS) or marine pollution (MARPOL).

    They are identified by name and the year of adoption by the Assembly, Such as the International Convention on the  Safety of Life at Sea, 1974.

    May have detailed technical provisions attached in annexes, such as six annexes to the MARPOL convention, each dealing with a different aspect of marine pollution.

     How many conventions are there ?

    About 50 ? Though checked up to 1998, 25.

     What is a Protocol ?

    A treaty instrument which makes major modification to a Convention which has been adopted but not yet in force. The Protocol usually speeds up the Convention’s entry into force. e.g. MARPOL 73/78, SOLAS 74/78

    Read more