12/02/2017 Center:Hull Examiner:R.AStevenson Candidate: Johnson, Idongesit Daniels Result: Passed Document check and brief discussion.
Down to business;
1) How do you know your boiler is operating correctly?
I started by telling him that when all the parameters are within the manufacturers manual. Then I mentioned boiler water chemistry, steam temperature and pressure being maintained, good quality steam, water consumption, fuel oil consumption, combustion equipment operating correctly. I then told him that when all the parameters mentioned above is within the values in the manual, you can then be satisfied that your boiler is operating correctly.
How do you maintain the steam temperature?
I told him that in my ship we use water attemperator. He asked me if I have not seen any other temperature control I said yes but that I have read about air attemperator. He needed explanation and I told him that combustion air from the fd fan is being circulated through the tube bank forming the attemperator then linked dampers is being used to control air flow through the attemperator. He added that this will also help to raise combustion air pressure. I further added that the problem with air attemperator is that sometimes the air will not be enough to maintain the temperature and that the dampers gets burnt off and the linkages sticking. He seemed to have been happy with that. .
What is your flue gas temperature?
It changes with load, from 180 to 230°C.
Why is the flue gas temperature maintained within that limits?
To avoid “cold end corrosion.
What is your ship’s superheated outlet temperature?
490 to 515°C
Why is the temperature maintained within that limits?
The primary parameters which determine the first point of turbine design are the temperature and pressure. Other points are derived from here. Excursions away from this limits will have a serious effect on the turbine materials due to the creep limit of the metals which are commercially viable. From the boiler’s point of view, the superheater design is a compromise between steam temperature and superheater life. Too high temperature will lead to burn out of the superheater tubes and supports, pipe work, valves and other components of the steam system.
How often do you carry out inspection of the boiler?
It normally comes up in the planned maintenance system, usually 4 to 6month, depending on the schedule of the ship. I further added that before ‘anything is done inside the boiler that there’s always a proper risk assessment and the boiler considered to be an enclosed space. I added the enclosed space entry procedure according to chapter 15 of the COSWP, 2015 edition.
What gasses do you test for in the flue gas?
What’s the values?
3 to 5% of the flue gas.
What of CO2?
We only monitor oxygen and smoke density and use that to adjust the air flow control.
What do you test for in boiler water?
Daily; Alkalinity, chloride, TDS/Conductivity, hydrazine, phosphate. Weekly; Hardness, copper, silica.
How do you know your turbine is operating correctly?
We do run turbine performance trial and kyma steam analyser. During the performance trial, the bridge team will be involved. The speed will not be altered, no machinery will be started nor stopped. The fuel oil flow meter and gas flow meter will be taken before and after the trial. The fuel and gas calorific values, the feed pump and TG exhaust temperatures, the steam inlet of steam air heater and the drain to 1p feed water heater also recorded. All these being plotted against the power take out from the turbine at that time will determine if the turbine is running well or not when compared to manufacturer’s manual.
Have you seen the main turbine before?
I have to be honest, no sir. I have been to dry dock twice but have never seen it opened which has been a bit frustrating for me really. The Examiner busted into laughter and said it’s always better to leave it like that if it’s not giving problems and I replied with a resounding YES. Laughing continued for a while.
What about the main turbine, what happens when the speed is either reduced or increased?
I didn’t seem to understand so he rephrased the question, how does the manoeuvring valve operate?
As soon as the telegraph is operated to either increase or reduced, the number openings in the manoeuvring valve will also be either increased or reduced. What I mean is that, manoeuvring valve consists of 5 or in some designs 7 valves which opens depending on speed requirement. For example, if 3 of the valves opens during dead slow ahead manoeuvring, if the speed is increased to slow ahead another one will open to make it four. It continues like that till nav full when all of them will be opened. The reverse happens when reducing speed.
You mean the valves opens sequentially? Yes sir
What about the astern turbine?
The astern turbine is either fully opened or closed, it does not operate in sequence.
What about the main condenser, have you done the tube cleaning before? No sir, I have not done tube cleaning before but have done the water box cleaning and anode replacement for a number of times. I quickly mentioned risk assessment, permit to work and enclosed space entry procedure before entering the main condenser.
What of deaerator, how do you know it’s operating correctly?
By monitoring and maintaining the shell temperature and pressure and ensuring that the temperature is not below the saturation temperature of water at that pressure.
Have you seen the inside of the deaerator before? Yes
Tell me how it is and how deaeration takes place.
The top part is made of stainless steel nozzles and further below are stainless steel trays. The feed water enters the deaerator from the top and gets broken down into fine droplets. The sprayed water passes through the steam atmosphere and gets scrubbed by the steam. This causes the dissolved gasses in the feed water to be released. The water passes down to the tray section in which further removal of dissolved gasses takes place. The gasses removed together with water mixture is directed to the gland condenser.
How do you ensure that the steering gear is in good condition?
Keeping the filters in good condition (pms), maintaining the oil level and testing the oil level alarm to ensure its working correct .Testing of power failure alarm and hydraulic locking alarm. Greasing of the rudder stock and the steering gear pump motors. Insulation testing of the electric motor and other routine jobs.
As a second engineer, a new c engine d crew member is to be sent to the engine department, how will you ensure he will not put himself and others in trouble?
On getting such notice I will find out the name of the crew member from the company’s OCS. ? I will then find out that is going to be his first time on-board, if not, the ships he has, been to, are they sister ships to this one? I will then check his credentials to see his level of training and experience. What certifications and experience has he got on this position? I can then ask people on-board if they know him to at least have a glimpse of him. On arrival, He relevant will be taken on the ship’s general familiarization and the engine room familiarization and the relevant checklists completed. I will ask him some questions to make sure he understands what he was told during the familiarization. I will then attach him to an experienced motorman who will be taking him on rounds and carrying out any task with him to make sure he understands what is going on.
What if He is a cadet?
He will pass through the general familiarization and engine room familiarization as well. I will then go through his training record book to be able to figure out how to help him complete his tasks. A mentor will be assigned (usually a 3rd engineer) who he will be working with. He will be told to go and read about the maintenance jobs that will be carried out the following day so that he’ll have pre knowledge of what is to happen. That will also give him the chance to ask questions where he does not understand. Based on his performance and participation what is being done, I will then ask him questions, put him through where he do not fully understand then sign off his tasks. I will also give him time for his personal studies.
How is the switchboard protected?
By circuit breakers, fuses and relays and also earth fault monitors/sensors.
How do you identify an earth fault?
By trying to find out which machinery was started the time the earth fault alarm went off and opening of the feeder breaker and closing them unit the earth fault disappears. Care must be taken not to open the breaker of an essential load or navigation equipment.
Which loads are fed from the emergency generator?
I mentioned the essential loads.
Which fixed fire fighting systems do you have onboard?
Foam, hyper mist, Co2, water mains and dry powder on deck.
Which area are protected by hyper mist?
Generators, boiler platform incinerator.
Mostly where we have electrical equipment such as switchboard rooms, emergency generator rooms, electrical motor room, engine control etc.
Foam protects the whole of the engine room except the switchboard rooms and engine control room.
It’s exactly one hour and I am happy to inform you Mr. Johanson that you have passed. CONGRATULATIONS.