Reefer Compressor oil properties

-Good chemical stability

(little or no chemical reaction with refrigerant or materials)

-Good thermal stability

(should not form hard carbon deposits at hotspots in the compressor like valves or discharge ports)

-Low viscosity

(good fluidity at low temperatures)

-Low wax content

-Low pour point (temp at which the oil ceases to flow)

-Low floc point (temp at which wax content in L.O. separate from L.O & refrigerant)

-Moisture-free

(may cause corrosion)

Desirable properties of refrigerant

-Low boiling point (otherwise operation at high vacuum becomes a necessity)

-Low condensing pressure (avoids heavier plant and reduces leakage risk)

-High specific enthalpy of vaporization

-Low specific volume in vapour state (reduces size and increases efficiency)

-High critical temperature

-Non-corrosive & non solvent

-Stable  under working conditions

-Non-flammable & non explosive

-Immiscible with oil (oil separator is a must if miscible)

-Easy leak detection

-Non toxic

-Cheap, easily stored & obtained

Refrigerant used on my ship (Plz know the same for your ship)

R134A----->CF₃CH₂F----> 1,1,1,2-Tetra fluroethane

-does not contain chlorine atoms and thus does not attack the ozone layer.

-But it is a green house gas, may be subjected to future legislation.

Reefer System Safeties

-HP cut out

-LP cut out

-Differential pressure L.O. cut out

-Cylinder head relief valve

-Relief valve in condenser                                               

-Unloaders / capacity controllers

-Non-return shut-off valves

-Pressure & temperature sensors

-Oil separator

-Drier (removes moisture in the line)

-Motor overload trip

-Belt driven (slips at overload)

-Mechanical seal

Parameters to be checked in refrigeration rooms

-Suction pressure

-Discharge pressure

-L.O. pressure

Typical room temperatures (±2)

Veg room           (+5°C)

Fish room           (-18°C)

Meat room          (-20°C)

** During defrosting process (manual/automatic), higher temperature may be shown.

REFRIGERATION basics

Cooling – final temperature may not be lower than the surroundings.

e.g. cooling the coffee or tea in the room.

Refrigeration- final temperature is always lower than the surroundings.

e.g. cooling the water with ice cubes.

Gas cycle

-involves gas with sensible cooling and no phase change takes place.

Vapour cycle

-involves phase change from liquid to gas in evaporator and gas to liquid in condenser.

*Vapour compression uses mechanical compressors.

*Vapour absorption uses thermal compressors.

Why SUPER-LONG STROKE ?

Super-Long stroke advantages

- Low quality fuel can be burnt 

(since more time is available for fuel combustion).

- Slow rpm is possible

(-->so large diameter propeller can be used -->propeller efficiency increases.)

- More time for heat dissipation to cooling water.

-better scavenging

-higher compression ratio can be achieved.

(so more fuel can be burnt per stroke and more power developed)

-reduced exhaust temperature

-reduced fouling, smoke, NOx

-increased thermal efficiency   

(heat converted into useful work / total heat supplied)

-power to weight ratio is more.

Classification based on stroke/bore ratio (For Man B&W)

Short stroke             : 2.6-3.2

Long stroke              : 3.2-4.0

Super-Long stroke : 4.0-4.7

Ultra-Long stroke  : >4.7

CRITICAL SPEED RANGE

Critical Speed Range (or Barred range)

-is the range of speed at which resonance may occur.

-Resonance is a phenomenon experienced when the engine’s operating frequency coincides with the natural frequency of the hull which results in vibrations of higher amplitudes than normal which is very dangerous.

-The critical speed range should be passed as soon as possible.

-In order to avoid operation of the main engine in critical (or barred) speed range, a quick-pass function is provided.

If the bridge command is within these areas, the lamps for critical rpm limit on the bridge and in the engine control room will illuminate.

The system will,

-during acceleration, keep the engine running below the lower critical speed,

-during deceleration it will keep the engine running above the upper limit.

Indications of Critical speed range :

- More vibrations can be experienced.

- The lamps for critical rpm limit on the bridge and in the ECR will illuminate.

*The speed range is marked RED in all Manoeuvring Panels. (Bridge, ECR, Local)

*The critical speed range is also labeled adjacent to the Manoeuvring Panels or near the telegraphs.

Means to reduce the amplitude of vibrations:

-sectionalizing of the shafting and

-interposing special couplings between sections.

-using vibration absorbers fitted to the crankshaft.

Means to avoid resonance is to adjust:

-speed of the engine

-mass of the flywheel or

-engine’s firing order.

MCR, NCR, IDEAL FIRING SPEED

Maximum Continuous Rating (MCR)

-The maximum output that can be produced by an engine continuously without causing failure to the propulsion machinery.

-It is the assured continuous power by the engine manufacturer to the ship owner according to the contract agreed upon.

In real scenario, this power is never used.

It may be used only at rare emergencies like:

- Extreme bad weather condition like a storm is (or is expected) on your course.

-Ship under pirate attack.

Normal Continuous Rating (NCR)

-The rating at which the engine can be operated most efficiently, economically and with least maintenance.

-typically 85~95% MCR

-this is usually the contractual output for which the propeller is designed.

Ideal Firing Speed

-The minimum speed/rpm required to fire the engine.

-typically 8~12% MCR

Values for my ship (plz know the values for your ship)

MCR ----->    23000kW @ 73.9rpm

NCR------>     20700kW @ 71.3rpm

Ideal firing speed

M/E-->           12rpm

A/E-->            200rpm

Question Bank for the FRESHERS

For the FRESHERs!!! (Chennai MMD only)

As a fresher if you don’t know what to prepare, this question bank should help you.

(From now on  you can’t say you don’t know what to prepare;-))

As a minimum prepare answers for the following questions for your first attempt. (for Chennai MMD only)

(Please don’t ask me for all the answers!!!)

Also keep track of trending questions for that week/month from FB group.

Recommended reference books:

Reed's Naval Arch, Ship Construction

Eric Tupper - Introduction to Naval Architecture

SOLAS, MARPOL (latest editions)

Reed's GEK

Reed's MEK

Lamb’s Q&A

Dennis T Hall -  Marine Electrical Knowledge

McGeorge - Marine Electrical Equipment and Practice

Fernandez  - Marine Electrical Technology

*All your ship manuals

NOTE:

*  Bulk carrier specific question

#   Tanker specific question

$$ Container specific question

Function 3

Basic naval arch & ship construction terms. (Refer Eric C. Tupper from Pg 414)

GRT, NRT, GT, NT and their significance.

LOA, LBP and their significance.

What is sheer and why it is provided?

Types of floors.

Stringers

Stiffeners

What is lightening holes?

What is freeing ports?

Types of bulkheads.

Advantages of corrugated b/h.

Collision b/h and its purpose and specialty.

What is Class A fire b/h? Where they are used?

Also prepare class B & class C .

Paint locker safeties.

Transverse section of ur ship.

$$ If container, why torsion box?

$$ What is TEU. Its types & their dimensions?

*If bulk carrier, why hopper  is provided?

*Bulk carrier special safeties.

*Ingress alarm regulations.

*Cargo hold smoke detection system.

What is bilge keel? from where to where it extends?

What is duct keel? from where to where it extends?

What is Load line/ Plimsoll line?

Load line diagram. What each item on it signifies ?

What is Fresh water allowance?

What is TPC?

What is Angle of Loll? How to correct it?

What is Margin Line?

What is reserve buoyancy?

What is freeboard?

What is condition of assignment of freeboard?

# * Why tankers have less freeboard?

# * What is Permeability? Permeability values for E/R, cargo spaces, stores, accommodation.

# IG system, composition of IG.

# Flammability diagram and explanation.

# Uses of pv valve, pv breaker, deck seal. (how many provided and where provided)

# Mast riser

Bonjean curve, Curve of Statical stability.

What is Free Surface Effect? What actually happens due to FSE?

How can it be avoided and how it can be reduced?

Know all the chapters in SOLAS  in their order?

* If u r bulk carrier then Chapter 12 complete!!!

What is ISM? Explain. Certificates under ISM and their validity, renewal etc.,ISM is under which chapter of SOLAS?

What is ISPS? Explain. (including security levels) ISPS is under which chapter of SOLAS?

Explain each Marpol Annexes and certificates & equipments under each Annex.

E/R bilges discharge criteria.

ORB entries.

What is SOPEP? What it contains? Items in SOPEP locker.

Fire Control Plan.Its contents.

Safeties in fire main. Why drains provided? Why relief v/v provided?

Isolation valve and its purpose. Normally kept open or close?

International Shore Coupling and its use. Its dimensions.

Standard Discharge Flange and its use. Its dimensions.

Explain Fixed firefighting in E/R.

If CO2,  how many bottles in CO2  room. How CO2  is calculated for E/R (formula)?

Draw CO2  extinguisher. Why horn? Why siphon tube? How to distinguish co2 extinguisher from others?

How foam is formed in Foam extinguisher?

S/G regulations.

S/G motor safeties.

S/G room safeties.

E/G regulations.

E/G supplies.

EPIRB

SART

Function 4b & 6

Draw various indicator diagrams. (Power card, draw card, compression diagram, light spring diagram) and significance of each diagram and how u get each of the diagrams?

What is Peak pressure, Compression pressure and where u get them?

What is MEP, MIP? And their values for ur engine.

What is compression ratio?

How Indicated power is calculated?

How BHP is calculated?

What is SFOC? How it is calculated?

M/E specification and what each letter denotes?

Advantages of super long stroke.

M/E interlocks.

M/E Safeties

M/E Cylinder head mountings.

What is Puncture valve? Its function. (MAN B&W)

Fuel injector parts and various tests done on fuel injector before commissioning.

How Starting air line explosion takes place?

Safeties in starting air line.

Types of scavenging.

What is overlap period?

Why scavenge air is cooled?

Types of turbochargers.

What is T/C surging. Reasons.

Piston ring clearances and their significance.

What is Piston Cleaning Ring(PCR)? And its purpose.

What is Anti-Polishing Ring(APR)? And its purpose.

One unit exhaust temp is high. Reasons?

How cylinder is lubricated in M/E? (If alpha lubrication then know its working.)

What is ovality of liner?

What is clover leafing?

M/E lube oil flow.

A/E lube oil flow.

M/E starting air system.

A/E starting air system.

M/E Crankcase inspection.

Stuffing box overhaul.

Why crankshaft deflection is taken?

How will u start the Generator manually?

Generator trips (both mechanical & electrical) and how to check the trips are working?

A/E piston overhaul & checks done on spare piston.

Working principles of FWG, Ejector P/P.

FWG troubleshooting like “vacuum not building up, high salinity etc.,”

Special arrangements in FWG suction line and Distillate outlet line.

Air compressor safeties.

Why intercooling? State as many advantages as possible.

What is Bumping clearance/clearance volume? What if it is more or is less? How it is taken?

Compressor valve parts and their functions. and overhauling procedure.

How will u start the Main Air Compressor(MAC) manually?

Why reefer compressor is belt driven?

Advantages of Vee belt.

Refrigeration circuit with block diagram.

How refrigerant is charged in the circuit? Both liquid & gas charging.

HP trip and LP cutout difference. Reasons.

 What happens if “Low charge”?

Why Back pressure valve is provided in vegetable room?

Thermostatic Expansion Valve diagram.  Function of TEV.

Operating principles of Purifier, OWS.

Purifier – Clarifier difference. State as many as possible.

How  motion transmission takes place from motor to bowl?

How will u start the Purifier manually? Manual desludging procedure.

Purifier overhauling procedure. Know the sequence.

Special tools required for purifier overhaul.

Purifier troubleshooting  like “purifier overflowing, bowl not closing, bowl not opening for desludging etc.,”

Boiler mountings.

Boiler safeties.

How will u start the Boiler manually?

Boiler gauge glass blow through procedure. And cross questions.

Boiler blow down procedure. Sequence of valve operation.Why so?

Why boiler water is treated?

Boiler water tests.

Boiler sampling line special arrangement.

What is cascade tank? Why it is provided? Safeties in cascade tank.

Oil in observation tank. Action?

Oil inside boiler(gauge glass). Action?

Sewage Treatment Plant (STP) working.

STP mountings.

What if blower of STP is not working?

Capacity of sewage holding tank.

Centrifugal p/p parts and their functions.

Overhauling procedure.

What is lantern ring?

Wear ring clearance value and why it is provided?

Globe v/v parts.

How to know the valve is a N/R valve or not?

Function 5

Safeties provided on MSB.

Generator paralleling .(conditions, procedures) and cross questions.

Generator   trips and their set point.

Explain Reverse Power Trip.

Explain Under Voltage Trip.

What is Preferential trip? And why provided?

True power, Apparent power, Reactive power.

Fuse-Relay-Circuit breaker differences. As many as possible.

Types of fuses.

Fuse ( Inverse current time)characteristics.

What is Single phasing?

Motor operating principle.

How speed of motor is controlled?

Induction motor working.

Synchronous motor working.

Motor name plate details.

Why we need starters?

Types of starters.

Explain each starter with diagram and where they are used. What each starter does? Also study SOFT STARTER.

Alternator working principle..

Alternator specifications.

Alternator maintenance.

What is Air gap? How much it should be? What if it is less & what if it is more?

Megger working  ,diagram and safety.

How insulation resistance is measured thro’ megger? What should be the IR value normally?

How insulation can be improved?

What is space heater?

What are the classes of insulation?

What is Class F insulation?

AVR working.

Components in AVR.

What is residual magnetism?

Transformer working principle.

How transformer is cooled?

Various voltages used onboard.

Contactor  maintenance.

Thermistor

Thermocouple

Battery room safeties.

Battery room maintenance.

Electrolyte used in Lead acid battery and Ni- Cd battery.

Chemical equations for the type of battery used on ur ship.

What should be the density of electrolyte when the battery is in FULLY CHARGED & FULLY DISCHARGED condition.

Difference b/w intrinsically safe & Explosion proof.

Intrinsically safe voltage & current values.

What is short circuit? How will u identify it?

What is open circuit? How will u identify it?

440v Low insulation alarm. Action?

A Piece of Advice for all Class4 aspirants out there.

Here is some tips, advice & mokkai for you all…:D

You might often think the questions asked in orals are very simple and wonder how someone could fail despite being asked such easy questions!!!

You are probably right about it but why would someone fail to answer such easy fundamental questions???

It is because they had probably forgotten the BASICS just like you would forget them too!!!

Trust me… this may happen with you too!!!! How????

Let me explain my own experience. When I was in my 6^th semester when my faculty said about how our seniors were performing in their orals and how they were unable to answer simple questions, I had always wondered how someone could be so dumb. Guess what, that is exactly what had happened with me too…:’(

If you had asked me about intercooling and its advantages in my 6^th semester, I would have filled atleast one A4 sheet. When I was asked the same during my orals, I couldn’t say more than just 2 points!!!

Similarly when the External asked me about TPC during my orals, I readily answered him “ sir, it is the tonnes per cm immersion …the weight required to change the ship’s draught by 1cm”.

For which he replied “everyone saying the same answer”. At that time, I wondered if there is only one answer how could someone come out with a different answer!!!!!!!

I hope most of you would have thought the same but trust me the answer was WRONG!!!

NOTE: An incomplete answer is as good as a wrong answer!!!

If I had asked the same question during your pre-sea training, you might have come up with an answer atleast this long.

So what should you do the next time when someone posts his questions??????????

-You shouldn’t just read through the questions and ask the answers for the unknown questions alone.

-Even if you get answers for those questions, you shouldn’t just stop there.

Please take time in understanding what it is all about. If you just knew what to answer and do the same during your orals, the surveyors will corner you through their cross questions. These cross questions are to ensure that you actually understand what you are telling and not just blabbering.

(This is the main reason why the surveyor would have accepted your friend’s answer but not when you gave him the same answer. So know the BASICS before you open your mouth next time before the surveyor. Some of the surveyors would wait till the last word comes out of your mouth. Each surveyor has his own way of cornering so don’t just bluff. Admit that you don’t know politely when you really don’t know.)

-If you know the answer, you should engage yourself in discussions and not just spectate. Only by discussions you will learn many new things.

(it is very simple… just comment whatever comes to your mind…

if it is correct, people will agree… and it will boost your confidence…

if it is wrong, someone will give you the correct answer…

or at the maximum, you may get a sarcastic reply… now your ego is disturbed… you will refer books and get the correct answer yourself!!!!!!

Either way it is a WIN-WIN situation for you…J)

-If you think it is an easy question, don’t just skip it.

Many a time you will ignore those questions and will convince yourself that you know the answer.

Each time you see that particular easy question, your mind will subconsciously reply “I know …I know… I know” and once when you are asked the same question during your orals, all you can remember is “I KNOW”only and not the actual answer…L

So the next time you come across an easy question, try answering it for yourself and see if you could recollect what you had learnt a long time ago and ensure actually “you know”…J

If not, then take a notebook and make notes about the same for future reference so you can revise it later and recollect. This way you can work on your basics.

Why should you prepare your own notes!!!!!!

You can refer notes from many sources but it is always advisable to prepare your own notes which can be understood just by glancing and will serve as a ready reckoner when you are in doubt. It will always come in handy for your final revision just before your orals.

It will also give you confidence that you have come prepared for the orals and not just for an MMD visit. If you feel down when waiting for the orals, you need not read anything but just glancing through your notes itself will be of some morale boost that you know something.

NOTE: Your notes have expiry dates!!! START FRESH EACH TIME!!!

Your notes’ validity is just one & half month. Prepare fresh notes for each attempt or at the least update existing notes because you might not be able to recollect/grasp all the stuff from your previous notes.

You might be able to remember points/ideas from your notes for the immediate appearance but not the subsequent ones. (just like you would forget the subjects of your previous semester in the ongoing  semester)

What should you do before asking a question in the group?

There is a search option available in FB groups. (only for those who are not aware of it yet)

For example if you wanted to know what is meant by GREEN SEA then just try all possible combinations like green sea, green water

Just go through each post and all comments. Your doubts might have already been answered by one of your great grand brothers!!!

Also you would get more idea from the discussions which happened earlier.

Similarly, you can also use this method to get a particular surveyor’s questions.

e.g. Choudhry, chowdhry, choudry, chowdry etc.,

What should you do when no one answers your question/doubt???

It is very simple. Just give a random/stupid answer yourself in the comment and leave it.

You would get response within next 24hrs for sure because some people cannot just sit back & tolerate any mistakes/wrongdoing before their eyes…;-)

(This is called “Aniyayathai kandu ponguthal”)

Learn from your seniors as well as your JUNIORS!!!!!

Your seniors can help you with their experiences. So when they say something just keep your eyes & ears open and follow them blindly.

(“Kelvi kekathaey palanaimattum anubhavi”)

No matter how smarter/brighter cadet you are, he is still your senior and he definitely knows something more than you. You also have the right to disturb him any time so be good to him. Believe me I had really freaked out some of my seniors to the FULL.

Even when I was told to find the answer for “Accumulation of pressure test” by Mr. Mathews, I asked one of my college seniors only. You might wonder what the big deal here is. What if I told you that  he was also told to come back by Mr. Mathews and he was first in that line!!! If I was in his place, I would have simply replied “I don’t know” but he explained me patiently because of which I had cleared my orals. Unfortunately he didn’t…L

Despite being in the same college for 3 yrs together I didn’t even know his name nor had I talked to him but when I was in need he helped me readily.(Thanks a lot bro… I owe you a million thanks._/\_ )

Sometimes you have get help from your juniors too. Trust me they can give you more points and better answers than you might think they will. Because they might have just wrote a test or an assignment in which they had written:

10 differences b/w safety v/v & relief v/v

What is TPC & its significance?

What is intercooling & its advantages?

Why a TIMER is provided for L.O. cut out in reefer compressor?

>>>>>>>>>>>>>endless>>>>>>>>>>>>>>>

Why saying someone to “google it” may actually be rude at times!!!!!!!

“Google it” is the most common answer you would come across. When I just finished my cadetship I had always wondered why people are so lazy to even google before asking/posting the doubts/questions in the FB groups that is when I was using an UNLIMITED DATA PLAN. But when it all turned to LIMITED DATA PLAN in a 6months time and  just WHATSAPP PLAN & FACEBOOK PLAN in an 8months time, I had realized how rude it is to say  “Google it”!!!!!!

So the next time when someone asks you to provide exact link to something, please think in this line before saying him to “Google it”

I’m still confused what should I do when a random member had posted his orals questions but has failed!!!

If I liked the post, it may send him a wrong meaning!!!!

If I had commented like “I’m sorry for you” or “hard luck” or “better luck next time”>>>etc>>>

again I might have spoiled his mood because he might have already recovered from that thought and I had probably reminded him and worsened it further.

Also who am I to console him? There are always his best friends & family members who are there to console him.

(For example: If a guy posts a sad post on FB… remember time passers just comment on the post but the real well wishers would send a  personal message or make a direct call )

And a kind request for you all.

Please use this group [MEO CLASS 4 PREPARATORYORAL QUESTIONS, MMD CHENNAI. ] exclusively for posting oral questions and subject doubts.

https://www.facebook.com/groups/358698064208866/

If you are going to flood this group for your general clarifications such as slot booking opening time,  seat booking opening time, whatsapp group formation, etc., remember one fine morning when you want to go through the type of questions asked in that week or in that month, you would find your own rubbish posts. (I actually wanted to use some other word here). So please friends it is for your own good and for the greater good of your fellow members. Please remove those posts yourself and help the group to serve its purpose better.

You can always use this group [ Chennai MMDClarifications ]for your general clarifications.

https://www.facebook.com/groups/1526795567540804/

And there is this confession page [Chennai MMDClass4 Orals Confession Page. ]  to post your oral questions anonymously in case you don’t want to receive those annoying notifications each time someone likes or comments about your post and wants to know about your results for no reason!!!

https://www.facebook.com/chennaimmdoralsconfessions

Thanks for visiting my blog.

This blog is for helping the beginners for Class4.

This blog will give you an idea about the minimum level of preparation required for Class4 orals.

This blog is purely a copy-paste work from various reference books, manuals, blogs, websites and discussion forums.

I have to compile a lot of topics from my notes. I will begin by posting answers for some common questions in the coming days. So if you need anything in particular, you can leave it as a comment here>>> Request a post <<<

I will make a post on it at the earliest if I already have the answers for them in my collection of notes…JJJ

Thank you.

Request a Post

This blog is for helping the beginners for Class4.

This blog will give you an idea about the minimum level of preparation required for Class4 orals.

This blog is purely a copy-paste work from various reference books, manuals, blogs, websites and discussion forums.

I have to compile a lot of topics from my notes. I will begin by posting answers for some common questions in the coming days. So if you need anything in particular, you can leave it as a comment in this post.

I will make a post on it at the earliest if I already have answers for them in my collection of notes…JJJ

Thank you.

What is TPC???

TPC is the weight which must be loaded or discharged for any given draught , to change the ship's mean draught by 1cm.


TPC= Water Plane Area* density/100

Significance:

TPC values for the draught range of a ship allow us to calculate how much cargo/ballast etc., to load or discharge to achieve a required draught.

My Final Encounter

This is what happened…JJJ

*******************************************************************************

When I was called to report to Mr.Mathews' cabin. I stood up from my chair and with a fake smile on my face proceeded towards his cabin. There were no ALL THE BESTs nor any GOOD LUCK wishes from my fellow candidates because they knew what was going to happen.

As I walked towards his cabin , all I prayed God was to give me enough strength to face my neighbours for next one & half month!!!(for real)

At his cabin door .

Me:  “Excuse me sir”

No response

Me again: “Excuse me sir”

Him: What for I should excuse u???

Me: Excuse me sir, may I come in?

Him: Come in.

Me: Stood next to an empty chair.

Him: Sit.

Me: Thank u sir.

Him: What type of ship u sailed in?

Me: 4500 TEU container vessel. (I gulped the word vessel)

Him: How can anyone sail in a container.

Me: Sir!!!!!! I sailed in a 4500TEU container vessel. (This time more loud &clear)

Him: Why didn’t u say container “vessel” before!!!

Me: But sir, I said it earlier too.

Him: No. I didn’t hear it. Listen if I’m not able to hear your answer then it will be considered as a wrong answer!!! Am I clear???

Me: Yes sir!!!Sorry sir…

He took my TAR book and was glancing through the pages and stopped in SHIP PARTICULARS page.

Him: What is your M/E?

Me: MAN B&W

Him: What was the BHP of your M/E?

Me: 23000kW @ 73.9rpm

Him: What was the SFOC of your M/E?

Me: Sir it was around 162-168g/kWh.

Him: Tell me that u had signed off long back so u have already forgotten about ur engine. Do u remember what value u wrote exactly in your TAR book?

Me: Sir… I think I didn’t enter any value!!! (I had a xerox copy of my SHIP PARTICULARS)

Him: Why didn’t u enter???

Me: Sir… this was entered as soon as I went onboard .I was in a haste to get signature so I might have missed it.

Him: What does MAN B&W stand for?

Me: It is the name of the engineers who designed the engine.

Maschimenfabriek Augsburg Nurmberg Burmeister & Wain

Him: So u r saying Maschimenfabriek Augsburg Nurmberg is name of a person!!!

Me: Sir…Burmeister & Wain are names of the engineers… Maschimenfabriek Augsburg Nurmberg may be names of some places.

Him: MAY BE!!! So u r not sure!!!

Me: Yes sir. May be!!!

Him: What is the TYPE of your M/E?

Me: 2stroke, crosshead type, internal combustion engine.

Him: TYPE!!!

Me: (again I said) 2stroke, crosshead…..(interrupted)

Him: I asked TYPE!!!!

Me: Sir… my M/E specification was 6S80ME-C9

Him: What is this “S”?

Me: Sir… it denotes Superlong stroke.

Him: What do u mean by superlong stroke?

Me: If stroke/bore ratio is more than 4.0 then it is called superlong stroke.

Him: U mean to say if I build a very large dimensioned engine then it can be called a superlong stroke engine. Tell me technical answer.

Me: Sir… Its power to weight ratio is more.

Him: WRONG!!!

Me: Sir… It has higher compression ratio so we can burn low quality fuel.

Him: WRONG!!! What do u mean by low quality fuel?

Me: Sir… Fuel which has higher residual components.

Him: What do u mean by residual components?

Me: The wastes from fractional distillation of crude oil.

Him: WRONG!!!

Me: if the calorific value is very low then we can say it is low quality sir…

Him : WRONG… Listen whatever answers you told is wrong and whatever answers you are going to tell will also be wrong.

Me:!!!!!!!!

[By now I understood what he was expecting from me. So I politely replied]

Me : Sorry sir … I DON’T KNOW…:p

[A WORD OF CAUTION: Don't tell "I don't know" at the very beginning. Just answer whatever u know about that question and when u are finished with everything then admit it!!!]

Him: During manoeuvring, bridge gives SLOW AHEAD . What happens then?

Me: (I was explaining him Main Engine Starting Air System from marineinsight.com

instead of MAN B&W Manoeuvring System by Sriram

https://www.youtube.com/watch?v=K4WR9ALTcIM

After I realized this I started explaining him again from the beginning but couldn’t explain him properly.)

Him: Who taught you this??? Chidambaram(Professor from AMET)???

Me: No sir… It was Mr. Ravikumar(Professor from AMET) who taught us IC engines!!!

Him : Atleast u should have told me various items in the system.

Me: Sir… but I can tell all the items.

(With that I started telling one by one.

He quickly interrupted and said no no…that is not the question…leave it.)

Me:!!!!!!!!!

[By now I already had 2 cross marks on his sheet.

I knew this would happen so I managed to keep my calm.

But couldn't help my mind from flashing dejected faces of my near & dear ones …L]

Him: U see the starting air line is abnormally hot during manoeuvring. What does it indicate and what harm can it cause?

Me: It indicates one or more cylinder air start v/v is leaking which can lead to a starting air line explosion.

Him: How can it result in explosion?

Me: Sir… if the air compressors &air bottles are not drained properly then oil will be carried over and may be present in the manifold and heat is available from leaking air start v/v and when engine is started it can cause an explosion.

Him: I mentioned that the engine is still running!!!

Me: Sir…it won’t result in an explosion unless the engine is stopped & started again… also there is bursting disc & flame trap provided.

Him: U had a bursting disc???

Me: Yes sir… bursting disc will be in the starting air manifold and flame screen will be present just before each air start v/v.

Him: What is the function of T/C?

Me: It utilizes the waste heat energy of engine exhaust and provides supercharged air to the engine.

Him: So what???

Me: Sir… the thermal efficiency of the engine increases.

Him: How???

Me: Sir… normally about 35% of the heat energy is wasted through exhaust… this heat is utilized to turn turbine which also turns the compressor wheel to supply supercharged air to engine.

Him: So???

Me: So we can supply more volume of air into the engine and burn more fuel.

Him: How can u supply more volume when the cylinder dimensions are fixed?

Me: Sir… by cooling the air in charge air cooler the density  increases . Density= mass/volume…so mass is increased…( I realized that I had told volume increases earlier)

Him: Mass increases or volume increases???

Me : Sorry sir … mass increases…

Him: Where do u come across “Accumulation of Pressure test” and what is it for?

Me: Sir …it is for the boiler to ensure that the boiler is of adequate strength since it is a pressure vessel!!!

Him: WRONG!!! So why don’t u have it for air bottle. It is also a pressure vessel.

Me: Sir… to check integrity of boiler…it is also a SOLAS requirement…

Him: WRONG!!! U call Venugopal(my HOD @AMET ) and ask him what it is for and let me know.

Me: Sir… it is carried out by shutting all feed inlets and steam outlets…

Him: I don’t want how the test is carried out… I want what it is for???

Just then Gopikrishnan sir came in and both of them were having a chat.

Gopi (to Mathews): how many more if u want I can take for some of them.

Mathews: 2 more files I have and I have asked 2more guys to come back. So if u want take these 2.

Gopi(after looking those 2 files, he returned one to Mathews): Sir I will not take for him. He already came twice to me and didn’t get any functions so let him try his luck with u.

Me: !!!!(my mind voice: sambo mahadeva)

After Gopi sir went. Mathews told me to find the answer and come back.

I asked the answer to one of my seniors who was also called back and was waiting for my turn again.

When it was my turn again:

Him: Did u find the answer?

Me: Yes sir…It is to ensure that the safety valves are of correct discharge capacity for the boiler.

Him: So it is not for the boiler???

Me: No sir …it is for the boiler safety valves and it is Classification Society requirement and not SOLAS requirement.

Him: Ok, then what about SUPERLONG STROKE!!!

Me: (Deep breathe)!!!

Him: So u found answer for only one question and not this???

Me: Sir… wherever I had referred it is given this much only sir… I couldn’t find anymore points…L

After a couple of seconds of silence, he started writing something on my files and said:

Him: Ok go.

Me: (with hesitation)Sir!!!!!!!!!!

Him: GO PASS.

Me: (in disbelief) Sir ???

Him: Go u have PASSED!!!

Me: Thank you so much sir…:D

I would like to thank all my friends, seniors, juniors and all the random MACHIs,MACHAs, BROs, DUDEs, BOSSes, JIs,BHAIs,THALAIs from all the Fb & Whatsapp groups for  helping me clearing this exam…JJJ

I wish each one of u all the very best for your exams.

Keep sharing your knowledge and keep spreading happiness around u…JJJ

Once again…Thanks one & all__/\__