JOB POSTPONEMENT

Job postponement in Maritime Industry

Definition Job postponement

When some job is delayed until a later time or date, that is a job postponement.
A job postponement can also be called a job deferral, and it means rescheduling job for later.
The postponement has a Latin root, postpone, "put after, neglect, or postpone."

In the maritime industry especially on tankers, there are procedures in use for job postponements.

Job postponements procedures aid in maintenance planning and will ensure that all machinery on board is adequately maintained and aim to achieve optimum reliability and safety of the personnel, vessel and environment protection.

Responsibilities

Usually, Chief Engineer and Chief Officer are the ones  responsible for making sure that job planning is done regularly and that postponement is requested as needed, following the predetermined procedure, for their respective departments

As the part o the procedure Technical Superintendent reviews postponement request and accompanying Risk Assessment together with any provided documentation following existing company ISM policies and industries regulations. Based on the Technical Superintendent’s review, the postponement will be approved or rejected.

Job Postponement Standard Procedure

While planning for maintenance jobs in PMS vessel might request, in exceptional cases, for extension/postponement.
Postponement is done following PMS software set up, but logically, the person in charge of the department will go to job planning section in order to retrieve the jobs and then highlight one or more jobs in order to request an extension filling up attaching necessary docs and sending the postponement for approval to TSI.
The person in charge should request a new date for doing the job (proposed date)  and the reason for this postponement request. Also, he or she must attach RA for every postponement request. RA must be done to ensure that every possible aspect and risk of allowing the postponement has been thought about and that mitigating risk measures have been implemented.
Upon receiving the postponement request, Technical Superintend in charge of the vessel will review the request  and will nominate criticality level basis on RA results, after mitigating measures have been implemented (LOW, MEDIUM and HIGH)
If postponement request RA is still with High Risk after mitigation measure is introduced, the postponement will be refused. The job will have to be done, if the job cannot be done due to lack of spares, lack of knowledge on board, or simply because for some reason it is impossible to do it safely. In that case, a temporary MOC will have to be done to introduce a temporary procedure for handling that equipment while spares are received or conditions for safe work are obtained.
( for MOC procedure visit https://www.academia.edu/38529460/Management_of_Change_Procedure_and_Guidelines_for_Oil_Tanker_Shipping_Company_.docx?source=swp_share )

The Technical superintendent can approve or reject the proposed date using the Approve or Cancel (depending on the reason and RA) but whatever the decision it must be communicated to the vessel ( approval or rejection).

When some job postponement has been approved, and new due date is implemented, both vessel and office has to keep control of the planning for doing postpone job as approved by the postponement. Usually, the PMS system highlight the jobs that have been already postponed and they come due again, the jobs are highlighted.

Following adequately set up a job postponement procedure is essential for safe and economically viable management of any vessel. In this as in everything proper communication between vessel and the office is the key to success.

  

Bibliography

Aimi, G. (2019). Advantages Of Postponement. [online] Forbes.com. Available at: https://www.forbes.com/2006/12/08/amr-product-postponement-biz-logistics-cx_ga_1208postpone.html#24cc68c517d6 [Accessed 26 Jun. 2019].

Aimi, G. (2019). Advantages Of Postponement. [online] Forbes.com. Available at: https://www.forbes.com/2006/12/08/amr-product-postponement-biz-logistics-cx_ga_1208postpone.html#24cc68c517d6 [Accessed 26 Jun. 2019].

  Disclaimer:

         “ Out of Box Maritime Thinker” © 2018 and Aleksandar Pudar assumes no responsibility or liability for any errors or omissions in the content of this paper. The information contained in this paper is provided on an “as is” basis with no guarantees of completeness, accuracy, usefulness or timeliness or of the results obtained from the use of this information. The ideas and strategies should never be used without first assessing your own company situation or system, or without consulting a consultancy professional. The content of this paper is intended to be used and must be used for informational purposes only.

DEFECT MANAGEMENT

DEFECT MANAGEMENT PROCESS ON TANKER VESSELS

Definition.

Before we start talking about the defect, let us first understand what defect is, in tanker industry defect is usually defined as:

"Any damages/breakdowns on critical equipment outside of planned maintenance that cannot be immediately repaired on board using existing spares and resources, i.e. require assistance/advice from office or third party."

Everything else falls under the category of unscheduled /corrective job or straight forward repair.

Defect management.

As far as tanker vessel maritime industry goes, defects are managed mostly by use of integrated software management system, i.e. Marine ERP that contains PMS.

The defect management process usually consists of four steps.

     The process starts when the vessel has a breakdown of critical equipment, then in software vessel creates defects and informs the office.

      The defect, as a rule, is always proposed by the vessel. Before opening a defect, the vessel management team will identify, by use of Risk assessment process, the risk involved in that defect and will implement risk-mitigating factors. Results of the Risk assessment will be used for Risk level notation of the defect.

     The Risk level is noted using the following wording: LOW-RISK DEFECT, MEDIUM RISK DEFECT and HIGH-RISK DEFECT each notation is obtained by using Risk assessment and getting results by implementing risk-mitigating factors.

     

     By Completing  all of the above the vessel sends defect proposal to the office, and that is when the next step in the defect reporting process and management starts.

     Here the Technical superintendent in charge of the vessel reviews the defect and checks all the corresponding documentation. The documentation consists of, but it is not limited to, Risk assessment, Root cause analysis (identifying what caused the defect in the first place), proposal to avoid reoccurrence, requirements for fixing the defect together with additional documents and photos.

      In step three, the vessel obtains feedback on a proposed defect ( Accepted, rejected, approved, acknowledged). In case of approval also proposed, and an approximate date for fixing the defect and getting equipment back online is given. If the due date for the defect is too far away and normal working condition cannot be obtained soon, temporary management of change should be implemented until the defect is closed, i.e. equipment condition restored to normal.

      In step four, the final step, the vessel is closing defect providing objective evidence together with comments and providing date completed. Defect becomes closed, and that means that all is done. When closing the defect, the extensive reason must be given, e.g., repairs and service reports, photos etc.

      Important

     The above process requires ship and office staff to communicate through all available channels, to ensure all are aware of the defect and of the measures to resolve the same (including near miss reporting, accident reports and typical day to day communications as appropriate).

       Disclaimer:

         “ Out of Box Maritime Thinker” © 2018 and Aleksandar Pudar assumes no responsibility or liability for any errors or omissions in the content of this paper. The information contained in this paper is provided on an “as is” basis with no guarantees of completeness, accuracy, usefulness or timeliness or of the results obtained from the use of this information. The ideas and strategies should never be used without first assessing your own company situation or system, or without consulting a consultancy professional. The content of this paper is intended to be used and must be used for informational purposes only.

Hull Inspection, Damage & Repair - Part IV

Hull Inspection, Damage and Repair ( Reporting and Assessing Structural Defects )  Part IV

Measures to Improve Fatigue Life 5 (+1)

Fit / Extend Bracket

Full Penetration Weld

Full penetration weld for about 250-300 mm at the end of the bracket.

Increase Thickness of Bracket at End

Improve Taper of the Face Bar

Reduce Thickness of the Face Bar

+1. Fix the End of the Stiffener

Care needs to be taken not to induce new hardpoints. In this case, the ends of the new bracket are directly above under –deck stiffeners.

Critical Areas- General

1. Frames in way of side ballast tanks and holds
2. Bottom plates in way of suctions
3. Hold bilge wells ( when they continue to shell plating)
4. Engine room wells ( when they continue to shell plating)
5. Distance pieces
6. Frames in ER close to SW pumps
7. Frames in way of chain locker when continued to shell plating
8. Plating below windlass
9. Structure in way of septic tanks
10. Areas not generally inspected
11. Floors separating FO and ballast tanks

Regular inspection, proper maintenance, planning and comprehensive record keeping is essential in maintaining vessels in good shape and in the safe condition.

Tanker Nomenclature – Typical Midship Section

Tanker Nomenclature – Typical Transverse Bulkhead

1. Bureau Veritas (2006). Mini Survey Handbook Part A - Ships in Service. (First ed.). France: Marine Division Ships in Service Management ( DNS).
2. Gutierrez, M. – Retired Senior Surveyor LR, 2018. Conversation/Lecture to/with Aleksandar Pudar from 18 to 21/9/2018.
3. Lloyd's Register Marine (2014). Hull Inspection, Damage and Repair. (Third Edition ed.). United Kingdom: First published by Lloyd's Register ,2009. 
4. Lloyd's register marine (2015). Hull Inspection, Damage and Repair. (First ed.). United Kingdom: Lloyds Register.
5. Researchgate.net. 2018. “ Pitting intensity diagrams” www.ResearchGate.com [Online]. Available from: <https://www.researchgate.net/figure/Pitting-intensity-diagrams-Figure-taken-from-2_fig4_320716318 > [Accessed on : 2 October 2018]. 
6. Marchant , T, Dr.Lomas, J & Dr.Callow, L (2009). WHITE PAPER:THE FEASIBILITY OF A CORROSION RESISTANT SHIP. [Online]. (1 ed.). United Kingdom: © BMT Defence Services Limited 2009 © Amtec Consultants Ltd 2009. Available from: <https://www.bmtdsl.co.uk/media/6098421/BMTDSL-Corrosion-Resistant-Ship-Whitepaper.pdf >[Accessed on : 2 October 2018]. 
7. Tanker Structure Co-operative Forum (1995). GUIDELINES FOR THE INSPECTION AND MAINTENANCE OF DOUBLE HULL TANKER STRUCTURES. (1st  ed.). England: Witherby & Co.Ltd.
8. Tanker Structure Co-operative forum (2014). Guidance Manual for Tanker Structures - Consolidated Edition 2014. (2nd ed.). Great Britain: Witherby Seamanship International.
9. Tanker Structure Co-operative forum (1986). Guidance Manual for the Inspection and Condition Assessment of Tanker Structures. (1st  ed.). England: Witherby Marine Publishing.
10. Tanker structure co-operative forum (1992). Condition Evaluation and Maintenance of Tanker Structures . (1st ed.). England: Witherby & Co.Ltd.

Hull Inspection, Damage & Repair - Part III

Hull Inspection, Damage and Repair ( Reporting and Assessing Structural Defects )  Part III

Stress Concentrations

Stress concentrations occur at any discontinuity in the structure with an intensity related to the abruptness of the change. For convenience, areas of stress can be divided into the following seven types.

Hard Point (more than 80mm from the structure)

The hard spot (or hard area) can be defined as:

• a point (or area) locally rigid in a flexible or less rigid structural element.
• also as a point (or area) where the deflection curve of a plate is
• abruptly interrupted by the effect of a very rigid member supported by the plate.
• as a point (or area) where there is an abrupt change in rigidity.

These abrupt changes in the deflection lines induce high local stresses. In those points (or areas) there is a great possibility to find cracks.

There are 3 types of hardpoints:

Hardpoint Nº 1. 

Bracket welded to a plate. Distance to the nearest stiffener >= 80 mm Consequences > Crack perpendicular to the bracket in the plate. Also, it can be caused by a “doubler”.

Hardpoint Nº 2. 

End of a face flat in a bracket Consequences > Crack in the bracket plating

Hardpoint Nº 3. 

Different deformation, under the same loads = Change of rigidity = Hardpoint 

The brackets should not end on unsupported plating.

The corners of trunks should not end on unsupported plating

SOLUTIONS:

The solution, although it may sound trivial, is to avoid or eliminate the hard points or to make a gradual change of rigidity

1) To place a small pad under the bracket toe. 

2) To extend the bracket to the next support.  

3) To place longitudinal support underneath the bracket.

4) To place transverse support underneath the bracket toe.

In other cases, we have to make the change of rigidity more gradual. Among the many possible solutions, we have to elect the best under the quality/cost criteria.

End of Bracket

The ends of brackets and of stiffeners are prone to fractures and therefore, should be examined carefully. 

We can consider three types of more frequent failures:

End of bracket Nº 1) - In this case, the welding connection of bracket or stiffener with the plating is fractured

End of bracket Nº 2) 

In this case, the bracket or stiffener breaks the support element

End of bracket Nº 3) 

In this case, the bracket or stiffener breaks the support plate.

In addition to three listed above there is also, Bracket Nº4) 

In this case, the bracket itself is broken.

SOLUTIONS for End of Bracket 

Change of Section

No1

No2

No3

In general, the solution is to modify the shape of the bracket (or to add a new one), although, sometimes, it is necessary to increase the size of the bracket.

In other cases, it will be necessary to extend the bracket to the adjacent stiffener or to incorporate a new stiffener to fix end the bracket.

Change of Section

Change of Section –Solution –Fit bracket

Change of Thickness

Solution – Insert an intermediate thickness 

Diminish the thickness difference and make the transition as gradual as possible, in the order of 3:1 or 4:1. 

Insert an intermediate thickness plate when the difference in thickness is more than about 1.5-2 times. Otherwise, improve the transition to 4-5: 1 by chamfering *

*A chamfer is a transitional edge between two faces of an object. A form of a bevel, it is created at 45° angle to two adjoining right-angled faces. A lark's tongue is a chamfer which ends short of a piece in a gradual upward curve, leaving the balance as a right angle.

Openings

Case 1

The solution for the photo above is to close the opening.

Case 2

The solution for case 2 – Increase the radius

If a flange is present on the opening ( as above) increasing the flange thickness in addition to increasing the radius will also reduce the stress.

Misalignments

Solution 1- Full penetration weld

Changing the fillet weld to a full penetration weld ( allows better continuity of the stresses through the misalignment.

Solution 2- Thicker insert

A thicker insert will also allow for better continuity of the stresses through the misalignment. Care should be taken to chamfer the ticker plate

to minimise the effect of the change of thickness.

Solution 3 Re –align

Re-alignment of structure in existing ships is never recommended as it will require a great deal of work to disconnect adjoining structure, and will induce other misalignments in the vicinity

Full penetration weld and a thicker insert will always be easier and cheaper.

Three Planes

(crack always on fillet weld)

When the three planes meet, such as at the intersection of a longitudinal and transverse bulkhead with a platform /stringer deck, there is always the possibility of the stress concentration arising at the point where they intersect. This can lead to fractures, although the type of damage depends on the size and type of the ship.

Solution 1 – Fit bracket (no scallop) in line with the plane on the other side

Solution 2 – Close scallops ( where the bracket is already fitted)

Difference Between Hard Points and End of Brackets

References :

1. Bureau Veritas (2006). Mini Survey Handbook Part A - Ships in Service. (First ed.). France: Marine Division Ships in Service Management ( DNS).
2. Gutierrez, M. – Retired Senior Surveyor LR, 2018. Conversation/Lecture to/with Aleksandar Pudar from 18 to 21/9/2018.
3. Lloyd's Register Marine (2014). Hull Inspection, Damage and Repair. (Third Edition ed.). United Kingdom: First published by Lloyd's Register ,2009. 
4. Lloyd's register marine (2015). Hull Inspection, Damage and Repair. (First ed.). United Kingdom: Lloyds Register.
5. Researchgate.net. 2018. “ Pitting intensity diagrams” www.ResearchGate.com [Online]. Available from: <https://www.researchgate.net/figure/Pitting-intensity-diagrams-Figure-taken-from-2_fig4_320716318 > [Accessed on : 2 October 2018]. 
6. Marchant , T, Dr.Lomas, J & Dr.Callow, L (2009). WHITE PAPER:THE FEASIBILITY OF A CORROSION RESISTANT SHIP. [Online]. (1 ed.). United Kingdom: © BMT Defence Services Limited 2009 © Amtec Consultants Ltd 2009. Available from: <https://www.bmtdsl.co.uk/media/6098421/BMTDSL-Corrosion-Resistant-Ship-Whitepaper.pdf >[Accessed on : 2 October 2018]. 
7. Tanker Structure Co-operative Forum (1995). GUIDELINES FOR THE INSPECTION AND MAINTENANCE OF DOUBLE HULL TANKER STRUCTURES. (1st  ed.). England: Witherby & Co.Ltd.
8. Tanker Structure Co-operative forum (2014). Guidance Manual for Tanker Structures - Consolidated Edition 2014. (2nd ed.). Great Britain: Witherby Seamanship International.
9. Tanker Structure Co-operative forum (1986). Guidance Manual for the Inspection and Condition Assessment of Tanker Structures. (1st  ed.). England: Witherby Marine Publishing.
10. Tanker structure co-operative forum (1992). Condition Evaluation and Maintenance of Tanker Structures . (1st ed.). England: Witherby & Co.Ltd.

Hull Inspection, Damage & Repair Part II

Hull Inspection, Damage and Repair ( Reporting and Assessing Structural Defects )  Part II

Considerations When Dealing With Damages

Fatigue

1. Alternate or cyclic loading
2. Loads lower than breaking load and yield stress

The material fatigue can be defined as the failure under alternating fatigue load or the propagation of a fracture due to a load of a cyclic nature.

Items of structure that form part of a ship may fail due to service loads and associated stresses, which are much smaller than the maximum breaking loads and stresses they were designed to withstand.

Fatigue

These loads are either cyclical or alternating in action.

In all types of fatigue fracture, crack start because of the concentration of localized stress in the component of the structure.

The fatigue curve

The fatigue curve shows the number of fatigue cycles at given stress before an item fails.

By reducing the stress in a location below the fatigue limit it should not fail again in the service life of the ship.

If a fatigue failure occurs early in the life of a ship the remedial action must be comprehensive in order to reduce the actual stresses to blow the fatigue limit.

If a fatigue failure occurs in a location late in the ship life it may be appropriate simply to repair as per the original design.

Corrosion Under Stress

 Accelerated corrosion will occur where there are high levels of stress. Even within the same space on a ship, corrosion rates at locations of stress concentration will be greater than in those locations where the stresses are lower. This can be seen particularly where sea water is present, such as inside ballast tanks where coatings have broken down.

The “stress cycle”

The acceleration of corrosion is cyclical and self-perpetuating; it occurs because wastage from corrosion leads to more stress on the area and in turn corrosion.

An area suffering from corrosion can rapidly deteriorate if coatings are not repaired or modifications are not carried out on the structure, which will reduce the stresses present.

The stress cycle often produces fracture lines at the point of the highest initial stress. In other cases, the area around the initial stress concentration becomes corroded.

Corrosion Under Stress

Progress(ive) of Corrosion

Inspections would be simple if the rate of corrosion was linear, however, the real rate of corrosion tends to accelerate over time.

Progressive corrosion

The stress cycle applies here too and once corrosion is established, it will become progressively worse unless preventive action is taken. 

Corrosion will continue to develop when:

The coating is not in good condition

The load that the structure is carrying is high; and

There is greater humidity and or higher surrounding temperatures

Solving stress and progressive corrosion :

Recoat protective coatings to stop corrosion

Increase thickness of structural members to reduce stress

Increase the radius of openings to reduce stress

Increase the thickness of flanges used at the opening to reduce stress

Close opening to reduce stress.

Humidity and Heat

In general heat and humidity affects the tanks mostly above the load line. 

The only solution to prevent this corrosion is the adequate maintenance of the coating

Higher temperatures and humidity will increase corrosion rates in unprotected environments. 

If they are both present, the effect is compounded and the rate of corrosion accelerates rapidly.

Areas on the ship that are most prone to increased heat and humidity  ( and therefore to accelerated corrosion) are the tanks above the waterline and those next to heated spaces.

Within a tank, particular attention should be paid to its uppermost part, especially where the tank boundary is exposed to direct sunlight.

Vulnerable tanks:

• Fore and aft peak tanks
• Deep Tanks 
• Side tanks
• Tween deck tanks
• Topside tanks
• Tanks adjacent to heated fuel oil tanks
• Ballast tanks adjacent to heated cargo tanks.

Age of Ship

The age of the ship is one of the most important factors to be considered when selecting a suitable repair. The same defect may have different treatment depending on the ship’s age.

The age of a ship and how much longer a ship is excepted to stay in service, are factors that must sensibly be taken into account when assessing the seriousness of a defect and establishing an appropriate repair.

When defects are due to fatigue, then the age of the ship gives an indication of the actual levels of stress. 

Remember the fatigue curve; fewer cycles to failure usually indicate higher stresses are present in the area of the defect.

Fatigue curve occurring on a new or young ship most probably indicate that significantly higher levels of stress than were expected at the time of design are actually present.

This could possibly be due to poor workmanship at the time of build or because of poor design. 

Correcting poor workmanship, if that is established as the cause, might include correcting the misaligned structure, fitting missing brackets, or inserting the correct grade and thickness of the material.

If, however, stress concentration has occurred due to poor design, then significant modifications to arrangements may be needed such as fitting much larger and softer bracket, closing openings by fitting lugs or collars, increasing grades and thickness of the material used.

Fatigue defects occurring for the first time in an older ship, say after 20 years of service, show that although the structure has eventually failed ( such as a crack developing) there was a little wrong with either the initial design or workmanship.

The most appropriate action in such a case would probably be to repair as per the original design condition; in the case of a defect that took 20 years to develop, such repair per should ensure another 20 years of service.

When there is the damage to a ship the ship’s age gives us information about the actual levels of stress that has contributed to the failure.

Stress Concentration Factor

The stress concentration factor in a given area is measured by the ratio ( SCF) between the maximum stress and the nominal stress and the nominal stress in the surrounding structure. 

A WELD MUST NEVER BE LOCATED ON A

 PLACE OF STRESS CONCENTRATION

References :

1. Bureau Veritas (2006). Mini Survey Handbook Part A - Ships in Service. (First ed.). France: Marine Division Ships in Service Management ( DNS).
2. Gutierrez, M. – Retired Senior Surveyor LR, 2018. Conversation/Lecture to/with Aleksandar Pudar from 18 to 21/9/2018.
3. Lloyd's Register Marine (2014). Hull Inspection, Damage and Repair. (Third Edition ed.). United Kingdom: First published by Lloyd's Register ,2009. 
4. Lloyd's register marine (2015). Hull Inspection, Damage and Repair. (First ed.). United Kingdom: Lloyds Register.
5. Researchgate.net. 2018. “ Pitting intensity diagrams” www.ResearchGate.com [Online]. Available from: <https://www.researchgate.net/figure/Pitting-intensity-diagrams-Figure-taken-from-2_fig4_320716318 > [Accessed on : 2 October 2018]. 
6. Marchant , T, Dr.Lomas, J & Dr.Callow, L (2009). WHITE PAPER:THE FEASIBILITY OF A CORROSION RESISTANT SHIP. [Online]. (1 ed.). United Kingdom: © BMT Defence Services Limited 2009 © Amtec Consultants Ltd 2009. Available from: <https://www.bmtdsl.co.uk/media/6098421/BMTDSL-Corrosion-Resistant-Ship-Whitepaper.pdf >[Accessed on : 2 October 2018]. 
7. Tanker Structure Co-operative Forum (1995). GUIDELINES FOR THE INSPECTION AND MAINTENANCE OF DOUBLE HULL TANKER STRUCTURES. (1st  ed.). England: Witherby & Co.Ltd.
8. Tanker Structure Co-operative forum (2014). Guidance Manual for Tanker Structures - Consolidated Edition 2014. (2nd ed.). Great Britain: Witherby Seamanship International.
9. Tanker Structure Co-operative forum (1986). Guidance Manual for the Inspection and Condition Assessment of Tanker Structures. (1st  ed.). England: Witherby Marine Publishing.
10. Tanker structure co-operative forum (1992). Condition Evaluation and Maintenance of Tanker Structures . (1st ed.). England: Witherby & Co.Ltd.