Lewis-Liverpool

Date: July 2017
Duration: Approx 1 Hr
Result: Pass
General:
A very unusual oral for Chiefs (in my opinion). Was heavily focused on the “nuts and bolts” side of
things and barely mentioned the legal side of things like ISM etc.
Started out, looked at my Discharge Book etc, saw I’d only been on yachts/ferries, and… same as my
EOOW and 2nd’s, he said that this is an unlimited ticket, so we’re gonna be talking about big ships.
There was virtually nothing yacht related from there on. In fairness though, he was almost
apologetic about the fact he was going to be grilling me on stuff I hadn’t necessarily seen. A real
good guy.
Also, he sat facing perpendicularly to me, leaning back in his chair, hands behind his head, looking at
the roof for at least half the exam, maybe more. I had been told to expect this, so not taken aback.
• Firstly, take me through the constructional differences between a slow speed 2‐Stroke
Crosshead and a medium speed 4‐Stroke Trunk Piston engine.
• With regards to the CLO Lube Oil you mentioned in the 2‐Stroke, take me through the
qualities you want in the various lube oils for both types of engines and why.
• What is scuffing and how does it appear in an inspection?
• Why are the TBNs different? What approximate figures for the TBNs in Crankcase of 2/4‐
Stroke and CLO? How does sulphur content affect the TBN in CLO?
• What is the difference between boundary and hydrodynamic lubrication.
• Ok moving on to a gearbox inspection. What are you looking for?
• Types of wear you find on gear teeth. Do you get scuffing on gear teeth?
(Elastohydrodynamic lubrication)
• Draw types of wear you’d find on gear teeth.
• Would you crack test the gears? How/Why?
• You mentioned Stress, talk to me about stressing, or over stressing a component.
• What types of failure can you see in a component.
• You mentioned fatigue failure, explain that to me. (Drew a graph of No. of Cycles/Stress),
went deep into detail here about amplitude, no. of cycles, reversing directions etc.
• What components can experience fatigue failure? (I said crankshaft, he pressed for more, I
said bottom end bolts which is what he wanted.)
• Do we replace everything, or do we re‐use items?
• How would you inspect a set of 2‐Stroke bottom end bolts when they had been removed.
What are we looking for and why?
• Any test in particular you’d do to see if there were cracks. (mentioned all the NDT tests, XRay,
MPI, Dye Penetrant etc.)
• You mentioned that some components can be ring tested with a hammer, but said you said
you wouldn’t do that to bottom end bolts for fear of introducing a stress raiser. What is a
stress raiser?
• What features of: A: Crankshaft, B: Propellor Shaft, are there to prevent stress? (was looking
for gradual run out/stepping up/down of the diameter of the prop shaft when changing size)
• What could cause localised overheating of a propellor shaft? (said shaft bearings or stern
tube bearing failure, inadequate lubrication etc. dependant on type of Stern Tube)
• You mentioned Grain Structure in the crankshaft, how/why is that important. How is it
maintained? How is it ensured?
• You mentioned adding the alloying elements Molybdenum and Vanadium as they can both
have a positive effect on grain structure. What other elements could/would you alloy with
steel and why? (Carbon, Silicon, Mangaese, Chrome, Nickel etc.)
• You mentioned Carbon, what effect would that have.
• What would a gear wheel from our earlier gearbox inspection be made of. Why that carbon
content? What is surface hardening, are gears surface hardened?
• Carbon content of ships plate?
• How do you know when a boiler is due for survey? Frequency? (2 yearly until the boiler is 8
years old, then annually, had just revised this!)
• What do you mean by visual external inspection during annual renewal, even when boiler is
newer than 8 years? What is an annual renewal?
• Who does Annual Renewal, Flag or Class? What jobs do flag/class do? (mentioned flag can
delegate jobs to class etc.)
• Ok let’s move back on to boilers. You’re entering dry dock, the yard workers are very keen to
get onboard and start doing a boiler inspection. How would you go about the inspection.
(wanted full PTW, enclosed space, Risk Assessment etc, told him that as chief I’d make the
guys stand down and cool their jets. Boiler needs 24 hours Ventilation min, and before any
of that happens, it must be drained/cooled/isolated etc. Procedures in SMS)
• How would you isolate/drain the boiler? Step by step.
• What isolations on the water side? What isolations on the burner?
• Boiler drained, how would you open it. (had already gone through Encl Space Entry PTW in
opening part of discussion)
• Where would you open first? (I said top manhole, wearing BA just in case)
• Slight side step briefly ‐ If this were a sewage tank we were inspecting, what gasses could be
present? What are the acceptable levels for O2, flammable gasses? What is LEL?
• Back to boiler ‐ What are you looking for inside?
• Where would oil come from? Where would scale come from? What is pitting?
• Where would oxygen in the water come from? How is it removed?
• Apart from heating the water, how else would we remove oxygen? Describe a test for
checking reserve of oxy‐scavenge.
• Ok, during the inspection you have found a crack in the shell of the boiler. How are we going
to effect a repair on that?
• What type of welders? What type of weld? Problems that could occur with welds, any welds
not just this boiler weld. Likely defects to find in a weld? Likely defects in a weld on a boiler
shell repair like this one.
• What type of testing would be performed on the repaired section of the shell, and the shell
in general after the repair? (After local NDTs on weld, he wanted a full Hydrostatic test of full
boiler last)
• Electronics ‐ What type of controller would you have for maintaining the water level in the
boiler?
• What is P, what is I, what is D? Why would you need a PID?
• What are the risks of using a more basic controller?
• What effects, on a boiler water level, would P have? and I? and D?
• What other types of controller could we have apart from electric/electronic?
• What is different about the air used in a pneumatic controller as opposed to the start air for
example?
• What is a diode? What does a diode do? What is a diode used for?
• With reference to rectification, Draw a wheatstone bridge.
• Anything else a diode is used for? (mentioned diesel electric propulsion converters,
regretted it immediately, as I remembered they use thyristors!)
• What is a thyristor? How are they different from diodes?
• Electrics ‐ What type of alarms do you have on the alternator of a generator?
• How do you know your generator is running effectively, electrically and mechanically.
• If there was high temperature on the windings, what could be causing it?
• What type of tests do you do on a generator alternator?
• How is excitation effected? Draw me an excitation system without slip‐rings. (I drew a
complete blank here, I knew how to draw it, but just couldn’t remember it…!) As a result, he
then took us deep into electrics!!!
• How does a generator produce electricity?
• How fast does the generator rotate? What factors affect the speed?
• What is the formula for frequency? What is meant by pairs of poles?
• What is synchronous speed? What are synchronous and asynchronous motors? where
would they be used? How are they different?
• HV‐ What are the additional safety procedures/features for working with HV?
• How do you do IR testing on HV? Talk me through the general process. (mentioned local
earths on/off before during and after the test as you would need to remove CME for test)
• If you’re looking at a light fitting, how do you know what type of fitting it is? What type of
fitting would you expect to find in say, the cargo area of a tanker?
• What is intrinsically safe? How would you know a fitting is intrinsically safe? What are the
Identifying/label scheme (letters) for intrinsically safe light fittings?
• Describe the construction of light fittings: intrinsically safe, explosion proof, pressurised etc.
• Where else would you have intrinsically safe equipment? This is also common to yachts,
where on your yacht might you have flammable gas? (I had to think about this for a while,
before eventually remembering the battery locker)
• What fittings in the battery locker? What s different about the construction of the light
switches? What is a two pole switch? Why would you use one? How is it different to a single
pole? What material is an intrinsically safe switch made from?
• Drydock ‐ You’re in the drydock, you’re going to the dock bottom for your first walk round.
What are you looking at first? Why?
• Why the rudder? (said if you hadn’t planned on working on the rudder, and found it was
damaged, you would need to know this and get it off asap as you may not have a lot of time
in the dock) How can you tell if it’s cracked?
• Supposing the ship had a CPP. What checks would you do that are unique to that type of
propellor?
• If it were a Fixed Pitch propellor. How would that be attached to the shaft (keyless tapered
bore, lifting arrangements attached before starting to prevent uncontrolled release), and
talk me through the process of removing this type of propellor.
• What do the initials M.A.I.B. stand for?
• What are the criteria for reporting an accident to the MAIB?
• What was the last M.A.I.B. report you read (Manhattan Bridge, forgot the Vivier Creel
Fishing Boat sinking one that came out last week!), what did you learn from it?
• What do the findings mean to you, How could we prevent that situation, or a similar
situation happening to you?
• What do you know about ballast water management rules soon to come into effect? What
are the proposed methods that will be accepted for treatment of ballast water?
• What are the other options for Ballast Water Management if not treating? What distance
offshore should you be when doing ballast water exchange?
• Does the MCA produce any other publications? What is an MGN?
• What MGNs have you read? Specific numbers.
• How do you stay aware of the publications issued by the MCA?
• OK, one final question… the IAPP certificate. How long is it valid for? How often is it
renewed? Who is it renewed by?
Stopped me there, said I’d given a good account of myself and he was going to pass me. It was a
proud moment!