[esailor Team]

20th June 2023
Examiner: Mr Zohurul Haque
Online via Microsoft Teams, the examiner didn’t mention where he was based
Call time 50 minutes

Examiner introduced himself and explained how the exam would be conducted; according to MIN 654, recently updated from MGN 69, he asked if I was aware of that. I said yes.
Checked my ID and he wanted to see my current CoC which I had to leave the room to get as I didn’t know I needed it infront of me.
He asked about my employment history and also asked about prior to working at sea.

He then said there would be feedback at the end if I wanted it in the event that I were to fail the exam. If you pass then that will be the end of the session.
The would be recorded from his side if I consented and he asked me to confirm that I could see the red icon appear on my screen when he started.

Start of exam
Your employment history suggests all 4 stroke medium speed engines, have you worked on slow speed 2 stroke engines? I said no
Can you tell me about your most recent ship? 110m motor yacht, diesel electric, PWM speed control for propulsion motors, twin shafts, fixed pitch propellers.
Can you tell me the constructional differences between large slow speed 2 stroke engines and medium speed 4 stroke engines, as many as you can? I started at the bottom and worked up, bedplate with holding down bolts, semi built crankshaft as opposed to 4S forged underslung crankshaft to a single casting block. 2S has A-Frames and Entablature held to the bedplate with tie bolts, crosshead and piston rod in a 2S, only a con rod in a 4S.
I mentioned the differences in exhaust valve arrangement and inlet valve as opposed to scavenge space and scavenge ports. Pulse turbocharging in 4S and constant pressure in 2S. Separate cylinder oil and crankcase oil in a 2S. Direct drive and reversible on 2S, gearbox or Alternator for PEM in 4S.
What is the function of the crosshead?
To allow for the long stroke of the piston rod and connect it to the connecting rod and to transmit the transverse forces through the guide shoes and guide bars into the A frames and then with the help of side struts into the hull of the ship.
On your large 4 stroke engine you are experiencing repeated premature wear on the last bearing closest to the output shaft, can you tell me what could be the reasons for this?
I said the possibilities are misalignment with the alternator, crankshaft deflection or LO supply issue.
How would you investigate each? Take crankshaft deflections, inspect LO supply channels for evidence of fouling and check LO flows out, check coupling to alternator for alignment using dial gauge.
Can you tell me about the Thrust bearing arrangement?
I mentioned the arrangement of the pads and that on a running hours based PM we would check the clearance by jacking it over to one side.
 
Can you tell me about the crankshaft sealing arrangement to the engine casing?
I said in my experience I have seen it overhauled at a major overhaul interval of 16,000 hours and that it was a double o ring arrangement held in by retaining covers. That the orings are joined/bonded and can leak crankcase oil out if they are not installed correctly.
Can you tell me about the methods of joining the intermediate shaft to the tail shaft?
Either bolted flange connection or muff coupling, which uses hydraulic pressure to expand the tapered bore and also hydraulic oil to lubricate the other shaft to allow for push up which is recorded and documented as per manufacturers instructions together with specified oil grade and working temperature.
What specifically about the bolts? He also asked about do the bolts or the flange take the torque?
I wasn’t sure so I mentioned that the bolts and holes would be designed in such a way as to not have any stress raising areas and that the bolts are of a specified tensile strength, tightened to a specification and they may have a locking arrangement which would be checked routinely and documented and finally that there could be locating dowels in the flange faces.
How do you control the speed of your propulsion motors?
Using Pulse Width Modulation, incorporating IGBT insulated gate bipolar transistors and a control system that switches the thyristors on and off to create a pulse, the time delay between these pulses determines the speed. To reverse, the control system reverses the firing order to the thyristors and the motor is reversed.
How would you bring one of your 4stroke engines into operation from long term storage?
LO, FO and cooling water tested and confirmed ok to use. Warm through the engine, take tappet clearances of inlet and exhaust valves, take crankshaft deflections, turn on turning gear and ensure free to turn and LO distributed. Check all alarms clear and no interlocks showing on monitoring system.
What checks would you do on the alternator?
Cooling leakage alarm test, bearing LO test/renew, bearing cooling check.
How would you perform insulation resistance measuring on it?
Lock out, tag out, safe systems of work as per company SMS, calibrated instrumentation and equipment.
How does an AVR work?
Voltage sensing unit with transformer and rectifier to produce low voltage dc signal, the compared with a set value using a Zener bridge, the error signal is amplified and controlled using a thyristor
Is there more power from 50Hz or 60Hz?
I’ve never considered it, so I’d have to calculate it to find out
Ok, can you tell me about your electrical installation again please?
690vAC 60Hz – diode rectifier to 1000V DC switchboard – static converter and transformer to 440vAC 50Hz
What determines the frequency?
Speed of rotation and number of pairs of poles
Tell me about ISM
This is the International code for the safe operation of ships, and for pollution prevention.
It comes from SOLAS chapter 9 and it requires that at Safety management system (SMS) is put in place. That it provides a specific documented safe system of working for each ship and aims to eliminate human error.
I then listed all the provisions, safety and environmental policies, levels of authority and communication between ship and shore, the DPA, defined job descriptions, Standard operating procedures, risk assessments and PTW, maintenance including record keeping and documentation, critical equipment and critical spares, reporting of accidents, near misses and non-conformities, and continual review and evaluation.
Can you give me an example of a major Non Conformity?
Sounding pipe fractured/broken. A corrective action plan needs to be agreed with attending surveyor stating method of repair, testing, re-inspection and a defined time scale for completion,.
Your exhaust gas boiler is heavily fouled, your actions in the event of an EGB fire?
Maintain water flow, bring online alternative generator to maintain power supply, shut down and isolate affected area as best as possible. Monitor temperatures until satisfied the temperature is coming down or atleast not rising anymore. Boundary cool as needed.
What else could be fouled?
I just started from the exhaust manifold and said the whole manifold, the T/C turbine, the uptake trunking.
You mentioned the turbo charger, tell me more
If the turbine section is heavily fouled it may affect the speed and balance
Tell me how you would prepare a boiler for survey?
Toolbox talk, observe risk assessment, manufacturers instructions, adequate time, any specific tools required, consider steam requirements, I said in my previous experience with two boilers this was fairly easy to achieve.
Isolate steam, feed water, sample lines, burner, economiser connections, lock out & tag out as record per SMS, allow to cool until pressure at around 4 bar, then open blow down valve and start draining, at around 2 bar open vent valve to prevent vacuum.
Crack top manhole incase of any steam and brace/secure. Crack bottom manhole to prevent inrush of cool air and thermal shock and then brace/secure it.
Then prepare for issue of enclosed space permit to work, as per company SMS, checklist prior to issue of permit which includes; ventilate the space, test the atmosphere with calibrated multi gas analyser, checking for oxygen content, toxic and flammable gases.
designated person at entrance and comms between this person and the designated people that will enter space and also comms to the bridge/ecr.
PPE as required, lighting tools, clear instructions on work to be done.
Then said the permit could now be issued but before anyone going in to clean we would allow the boiler to cool if needed and we would visually inspect for scale corrosion and deposits (from the manhole opening) take photographic evidence and document and record it.
How would you prepare the safety valve for the attending surveyor?
Dismantle and lay out all components in workshop, we would be checking for corrosion or damage to the sealing faces, the spindle, the spring and the valve housing drains. Would also check the condition of the easing gear.
Can you tell me about MARPOL annex 4?
This is concerned with Sewage pollution prevention
What certificate do you have for this?
International sewage pollution prevention certificate, with type approval certificate for the treatment plant and a certified document stating the allowed discharge rate of untreated sewage considering the vessels speed and draft.
How would you deal with sewage in port?
I said our treatment plant has type approval for treated discharge in port
If the port didn’t allow discharges, your holding tanks are full and there is no fixed shore connection?
I said possibly arrange for offload to sewage tanker
No in this instance there is no possibility of shore offload, what else would you consider?
I said the only other thing I can think of is to reduce or stop the production of waste for the time we are in port
Your shoreside office suggests a conversion of Ballast tanks to additional sewage holding tanks, what are your considerations as a chief engineer?
I said tank coating, pumping arrangements and modification to pipework, recertification of ISPP as the tanks are listed in the supplement to the certificate.
What else?
Updated ships drawings to show modifications, complete removal of connections to the old ballast system, blanking off of those pipes.
You mentioned earlier about sounding pipes, is this the only way to determine the level in these new sewage tanks?
I said no we have tank level sensors
How do your level sensors work?
I said they are measuring the hydrostatic pressure, using a P/I converter then a 4-20mA signal to our monitoring system in the ECR
Then I realised – these would have to be recalibrated for sewage instead of ballast water.

That’s the end of the exam, congratulations you have passed.
You will receive an email shortly confirming this, that’s the end of the call now, have a good day.

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