Monday, July 9, 2012

CARGO TANK INTERNAL INSPECTION ON CHEMICAL TANKERS- CAPT AJIT VADAKAYIL


CARGO TANK INTERNAL INSPECTION ON CHEMICAL TANKERS- CAPT AJIT VADAKAYIL


Chemical tankers will clean the cargo tanks and associated pipeline systems prior to declaring NOR and arrival at the load berth.



In modern times , it is essential to take plenty of pictures from all angles , with all ports open to allow daylight in.  Once you load the pictures it in your computer, you can be surprised that the camera has pinged what your eyes could not --- and you can zoom in too.

A smart tank inspector knows the position of your tankcleaning machines, the blind sectors of the jet and if you gave given machine drops .  He knows where to look.

Special attention should be paid to the condition of the tank coating in the case of epoxy coated tanks and, in particular, to the presence of blisters and flaking of the coating.


Unbroken blisters may contain residues from an earlier cargo as will loose or flaking coating.


Depending on the charterer or shipper requirements, the inspector may be asked to estimate the percentage of coating missing or damaged.


Reference to the vessel’s previous cargoes can have a bearing on the further action required from the crew when determining the likely effect the condition of the coating might have on the cargo to be loaded.


Attention should also be paid to the cargo tank, pipes, drop lines, pump casings, suction wells and heating coils. These items can form shadow areas and often receive less than adequate attention during tank washing.


Inspectors cannot, of course, visually inspect the internal condition of pipelines for their full length and the inspection report should clearly state the applicable limitations.


Vent and inert gas lines are usually visible at the tank entry point and could contain prior cargos, polymerized material, or washing residues, that if present, could contribute to contamination.


Deck lines will have drain points and these should be opened in case residues from tank washing operations or prior cargos are present.


Wall wash test by inspectors/ suryeyors :--

Tank surfaces must be dry.

Discoloured or broken coating sections on tank walls should be sampled as follows:

Where such areas are less than 20% of total surface area (excluding deckheads), the washings should be included with those of the rest of the tank.

Non typical areas should be sampled and tested separately. Samples should be tested in a shore based laboratory.

The minimum number of areas to wall wash depends on the tank capacity.

Tank capacity less than 500 cubic metres--     5 areas

Tank capacity 500 to 1000 cubic metres--      7 areas

Tank capacity greater that 1000 cubic metres--       9 areas


Wall wash sampling procedures may cause a previously gas free tank to develop an unsafe atmosphere and personal protective gear should always be worn and breathing apparatus may be required.


There are limitations on the extent to which inspectors can visually inspect all parts of the loading system, vessel and shore, and so they will  inquire about the steps taken by the vessel to avoid or reduce the risk of contamination.


Loading/discharge manifolds, vents, and inert gas lines  can only be inspected where visually accessible.  Extensive areas of the pump and piping systems can only be assessed on the basis of information obtained from the Chief Officer in respect of tank cleaning operations and previous cargoes.

 Prior to loading “first foots” in tanks , an initial shore line sample should be drawn and visually examined to ensure the cargo is clean and bright and free of suspended matter. This first foot sample at the manifold must be drawn with the manifold valve SHUT ( you cant do this for screw pumps and reciprocating piston pumps )


Subject to wall wash tests (where applicable) and receiving laboratory clearance, the vessel will then be able to start loading “first foots”.


First Foot samples are required to determine whether any contaminants within the vessels loading systems have survived cleaning regimes that might have a detrimental effect on the cargo to be loaded.


Cargo Tank Coating Suitability

 The following is to  understanding potential contamination problems that may arise with chemical cargoes.


Zinc silicate, phenolic epoxies and pure epoxies are the most commonly used generic coating systems in cargo tanks for the carriage of chemicals.

 They vary in their resistance to cargoes and all have limitations in carriage.

 The principal limitation in the use of zinc silicates is that they are only suitable in a narrow pH

range of approximately 5.0 to 9.0.


Phenolic epoxies are generally able to carry a wider range of low molecular weight cargoes and have a higher free fatty acid resistance

 The cargo resistance of coatings of the same generic type can vary between manufacturers and, hence, the manufacturers Resistance Lists usually available aboard the vessel should be consulted should there be any doubts as to suitability of any particular cargo.

Some coatings are temperature sensitive.  Cargo carriage requirements may require heating, and temperature control should match the coating operability range.

Organic epoxy coatings have the propensity to absorb cargoes during a loaded passage. The contamination potential to a subsequent cargo is therefore considerable as:

Large quantities can be retained

The amount retained after different time periods is not well defined

Variable absorption/desorption characteristics are found between different coating types

Variable absorption/desorption characteristics are found within the same generic types from different manufacturers.

Different rates of absorption/desorption are found between different cargoes

Factors such as coating thickness, temperature and tank cleaning also have an influence on absorption and desorption.

With some chemical cargoes, absorbed material can survive both further intermediate cargoes as well as extensive tank cleaning operations

The shore tank inspector is NOT a bird. He goes down the tank ladder . On the way, he will touch and rub certain areas. Be sure that these areas are good.  

At the tank dome itself  , before entering , the shore surveyor  will smell the tank, and sometimes this smell could come from dirty gasket of the tank dome cover. He will refuse to enter if the previous cargo has any carcinogenic percentage .

Cargo hoses used for looping forms part of the pipelines . Number them and have a list of the last 3 cargoes handles by these hoses.

If the previous cargo was insoluble in water, check the threads of all bolts inside the tank, minutely.

Sometimes it so transpires that after Methanol / potable Ethanol discharge, the tank was vented and the tank fails at the load port for the same cargo, to be loaded again. Just make sure the horizontals and slanted surfaces do NOT have any sediment, by rubbing a wet black/ white cotton lint free cloth.

Nowadays surveyors are hand in glove with shippers ( for a ulterior reasons ) and they fail the tanks for moisture condensation. Don’t be na├»ve.  The principle to apply here is -- warm moist air, always condenses on a cold steel bulkhead. This is the reason why chemical tanker-men cannot be dimwits.



CAPT AJIT VADAKAYIL
29 years in command

17 comments:

  1. Dear captain,

    Recently after watching flatliners i've been searching what actually will happen this dec 2012 than i came across these two clips in youtube and it actually shows what really can be expected in this coming december which really match few of your articles . The first has the detailed explanation what and when it will happen and the second is describing after it happens. I sincerely want your opinion on these two video clips.

    http://www.youtube.com/watch?v=1q2Du_DkKbo
    http://www.youtube.com/watch?v=OeZ2DT1yqh0

    Thank you and really looking forward your opinion on this.

    Regards

    rajan

    ReplyDelete
  2. Dear Captain,

    I've uploaded the ebook on pdf format in the below link which is exactly the same information that been explained in the first video link

    http://www.4shared.com/account/dir/yQRZN5By/_online.html?&rnd=39#dir=101734874

    Thank you

    rajan

    ReplyDelete
  3. dear rajan,

    i just saw the first video 1.5 hrs of BORING viewing.

    first of all MAYAN calendar is made by maya danavan , who wore the surya siddhanta and ran way to patala ( peru ).

    hence the maya calendar is nothing but the indian calendar.

    the mayan calendar does NOT end of 21st dec 2012 at 1111 UTC.

    this time is just the time of crossing of the ecliptic ( path of sun ) with the galactic equator ( equator of milky way ).

    there will be no apocalypse, as this guy says.

    as i have explained in several of my posts , the star dust will upgrade our human DNA. the indian maharshis who had 12 strand NIL junk DNA could do wonders--as is projected in our ancient sanskrit texts.

    the human body is a wonderful machine-- the ultimate , which can never be excelled.

    what he says about the crop circle is partly right. if it is made with ropes and boards, the crop gets destroyed. but if it is made with scalar rays, the bent areas ( nodes ) will be fused thick , and the crop stalk is still alive.

    he dwells 90% on crop circles without understanding it. just a waste of time.

    punch into google search CROP CIRCLES MYSTERY SOLVED VADAKAYIL

    capt ajit vadakayil
    ..

    ReplyDelete
  4. hi rajan,

    the second clip of 21 min, " what happens if you do or dont ascend " is bullshit of the FIRST order.

    capt ajit vadakayil
    ..

    ReplyDelete
    Replies
    1. Dear Captain,
      Thanks and really appreciate your help on this matter . Have read through your article on crop circles and now i'm clearly understood .

      Thank you

      regards

      rajan

      Delete
  5. Dear Captain, I am a shipboker and I am trying to fix a Mediumrange MR with Zinc Coated tanks.
    I understand Jet is not loadable on this vessel, as well as Vegoil/Palmoil.Is it correct?
    Thanks

    ReplyDelete
  6. hi marta,

    read my post ZINC SILICATE TANK COATING CHEMICAL TANKERS- VADAKAYIL.

    very bad idea to load jet fuel in zinc tanks.

    with palm oils--cleaning after discharge will be a nightmare.

    i had once loaded MEG FG in zinc tanks- too much times was wasted at load port houston in inspecting the tanks, and then ultra-severe testing of first foots etc. same problem in disport, with testing outurn samples. we passed, but it was NOT worth the tension , and I wont do it again.

    capt ajit vadakayil
    ..

    ReplyDelete
  7. Sir,

    request your perspective on the below.
    http://www.youtube.com/watch?v=o1Hw8DVLw-A

    Does this Answer what Rajan is asking, and what about the looking Glass, he says it was in Libya and then was Given to Iraq???? Is it True???

    ReplyDelete
  8. hi,
    many companies have started taking victualling in their own hands. we only send them the ROB. some people say this system is better because it prevents any corruption by the master & c/ck. I have personally supported this system. makes my life o/b as a master more easy.
    the crew morale is high when the messing is done in a proper way. these small things go a long way in deciding the output of crew members.

    what system do you like capt?

    also, i had read ur article about milk. on the parcel tankers we always make sure that we have enough milk in the messrooms. its said that milk is good for the crew after handling chemicals(during t/c ops).
    what are ur views on this?

    ReplyDelete
  9. hi suresh,

    this video is very long 1hr 36 min --andi managed to sit through for 1 hour.

    ALL BULLSHIT.

    he has said some things i have written in my posts about DMT ( spirit molecule )etc.

    pine cone is MERU and NOT pineal gland.

    he talks about chakras , kundalini, mandalas and then called Lord Shiva as a SHE.

    he tries to put the bible in good light ala vedanta --actually bible is so shallow that it just does NOT fit in.

    the looking glass is nonsense.

    to me david wilcock--has an agenda.

    He talks about rothschilds involvement in the bolshevik revolution, french revolution, 2nd world war-- all true.

    then gives total undiluted CRAP--about extra terrestrial stuff--which makes me wonder if he is crypto double agent--

    you dont have to wash ahnds after reiki--he does NOT understand reiki.


    just a waste of my time.

    capt ajit vadakayil
    ..

    ReplyDelete
  10. hi anand,

    master MUST feed his crew!

    after 3 decades of command i am firm about this.

    master is the father--rest in the crewlist are all his children.

    punch into google search GLOBAL WARMING AND GREENHOUSE GASES- VADAKAYIL for my take on milk.

    capt ajit vadakayil
    ..

    ReplyDelete
  11. Hi Capt,
    Needed some info on tank cleaning after carrying veg oil,specially soyabean & fish oil.
    Following cycles were used for both grades.
    1 hr SW ambient + 2 hrs Hot water(60deg) + 2 hr hot water (60deg).
    after doing the above we cd still find traces of dry oil, especially in soyabean tanks.
    In the fish oil tanks, some isolated parts on the bulkheads we found some white traces, which appeared like scales. a bit difficult to remove only with water washing.
    Can you please advise what is the best way to remove such traces, as well as what would be the best way of cleaning these tanks.
    Als if after washing tanks with fish oil, what would be the best way to eliminate the smell.

    Regards
    Adarsh

    ReplyDelete
    Replies
    1. hi aa,

      i usually do OT take such questions.

      however--

      A CARDINAL MISTAKE HAS BEEN MADE.

      soya bean oil is a DRYING oil and has to be COLD washed first-- TILL ALL TRACES OF SOYA BEAN OIL DISAPPEARS.

      use caustic potash for recirc -- put a extra portable machine through the tank dome-- give extra drops.

      after this use HOT water at 75 deg C.

      if you have already put caustic, which you must have -- recirc with phosphoric acid ( if tanks are NOT zinc or epoxy.)

      smell will disappear with acid recirc.

      capt ajit vadakayil
      ..

      Delete
  12. intend to load Crude degummed soya bean oil but vessel desige is without drop line . Circulation of cargo will not be possible .

    pls advice to avoid large accumulation if sediments at the bottom

    salman

    ReplyDelete
    Replies
    1. hi s,

      on loaded passage , on good weather days , alter course to avoid sea spray--

      -- connect portable flexible hoses to the delivery line and do recirc bottom to top surface -- just to keep pump suction clear . .

      capt ajit vadakayil
      ..

      Delete
  13. Thank you very much for such a nice information regarding Cargo Inspection Services with illustration on each step. I shall very much appreciate if you could please include guide to On-hire and Off-hire Bunker Survey with respect to marine inspection.

    ReplyDelete
  14. Buddha Zorba
    April 12, 2015 at 11:27 PM
    Hello Sir,
    How is restaurant food different from home made food ?

    I mean in terms of processing, to quicken cooking, additives, short cuts, tips and tricks, freshness of food products,
    quality of oil used by them ?

    ReplyDelete
    Replies
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    Capt. Ajit Vadakayil
    April 12, 2015 at 11:30 PM
    hi bz,

    there is an ingredient called LOVE included in home cooked food.

    my wife cooks for me and my younger son daily.

    we can afford a dozen cooks .

    capt ajit vadakayil
    ..

    ReplyDelete