Cochin Shipyard Ltd.
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Industrial Training Report
COCHIN SHIPYARD LIMITED
B.TECH (NA & OE)
INDIAN MARITIME UNIVERSITY (IMU)
I feel myself privileged to be the part of COCHIN SHIPYARD LIMITEDfor industrial training where every person has shown me the right direction with their helping hand and constant support all through my training period.I am very thankful to JOSEPH N J (DGM Training Institute) for providing opportunity for industrial training. I am undeniably very thankful to the various DGMs of various departments and all the staff who have helped and guided us all through our training.
In Cochin Shipyard Limited steel plates are processed and manufactured into panels for building a ship. Also they are called plates, sheets and layers. These panels are prepared in prefabrication chamber by welding elemental sections together that are being processed in hull shop where in turn steel plates and sections are processed in hull shop that are being brought from steel stock yards where all steel plates and sections are being stored. In Steel Stock Yard the steel plates and sections are stored in the form of stacks or piles which further are taken to hull shop and prefabrication chamber for the preparation of ship panels.
In this shop marking, cutting of elements to the various sizes and forming them into different shapes as per requirement and marking them unit wise for feeding to the sub assembly and assembly shop is done.. The principle material used for hull construction is mild steel. For the ship building purpose, the plates and sections are usually made of mild steel containing 0.15 to 0.25 % carbon and 0.4 to 0.7 % manganese, phosphorous 0.035 to 0.06 %, sulphur 0.03 to 0.06 % strength of from 26 to 32 tons/Sq.inch with an elongation of 16 to 20 % in 8 inches lengths depending upon the thickness of the plate.Generally steel drawing office will allocate the material as per the schedule. The steel stores will issue the material in requisition of Hull Shop.All plates are then mangled, shot blasted and painted. At This process is being done to prevent corrosion.Markers will mark the plates and sections with the help of templates and drawings. They will write complete process on marking, material, type of edge preparation, forming, cutting lines, dispatching, destination, etc..Other elements are marked on the steel plates using the wooden templates prepared in mould loft and cut in other gas cutting machines.There are Hydraulic presses with various capacities and up to maximum 2000Tons forming the plates. Rolling machines, cold frame bending machines, shearing machines, cambering machines, straightening machines, Plate preparation plant, section preparation plant etc. are the important machines in the shop which have the capacity to produce elements up to 2500Tones per month. The elements proceeded in the Hull Processing shop and assembly units inspected for their workmanship of the steel complex, dimensional accuracy by the quality control of the steel complex and presented to the classification society surveyor for inspection are lore they dispatched to block storage area or berth for assembly erection.
Spray Painting Section
Steel plates are first transferred to heat treatment line to de-scale the plates from rust, dust and impurities. It is the first step for any plate before it used for any process in the hull shop. The de-scaling process also includes a hydro leveler and spray painting section.In plate treatment line steel plates are processed under various machineries to make them fit for production of ship panels. The following are the various machinery sections that are present in the plate treatment line. The complete step to step procedure is shown alongside.
1) Captivator2) Hydro-Leveler3) Heating Chamber4) Blasting Chamber5) Spray Painting Section6) Drying Chamber
3.1.1) CaptivatorThe steel plates from the steel storage yard are lifted onto the captivator by a magnet and placed onto the inclined portion (the head section) of the captivator. The head section consists of three important rollers namely free roller, magnetic roller and motorized roller(s).
Maximum plate load 10 TonsMaximum plate size Length14m,Width3.65mMinimum plate size Length 3.65m, Width 1.5mPlate thickness Max -50mm, Min -5mmHoisting speed 8/4 M/minTravelling speed 90/30 M/min.Roller Speed 30 M/minTrolley Speed 30 M/minNumber of piles 3Max height of piles 600mmMain voltage 3*440 V, 50 HzPilot voltage 220 V, 50 Hz
Hydro-LevelerA hydro-leveler is an 80 ton capacity hydraulic powered machine to level the plates and free them from any curves, bends and distortions so as to make the plate perfectly flat.
Specifications:Hydraulic pressure 315 Bars and 100 BarsHydraulic medium Mineral oilWorking pressure Centre beam (doxvn) 315 BarsTest pressure centre beam 395 BarsWorking pressure centre beam 100 BarsTest pressure 125 Bars
Heat Treatment Line Process Layout
Working pressure 315 BarsTest pressure 395/395 BarsDown/Up Speed 3-4 m/min
3.1.3) Heat ChamberThe plates are then moved into a heating chamber where they are heated so as to remove moisture content and other liquid material such as oils from the surface of the plates.
3.1.4) Blasting ChamberBlasting is an important step in the heat treatment line. It removes all the impurities on the surface and makes the surface clean and pure. It consists of 8 roto blasts, four on top and four on bottom. Small spherical grits made of mild steel are made to incident on plates with great force and high velocity. This will result in the removal of rust and mill scales. The grit is fed from overhead tank then into motor (impeller). It has axial entry and radial exit. Its equipment is used for the purpose of removal of rust and dust particles from the plate.
3.1.5) Spray Painting UnitThe blast is equipped with micro computer which enables paint spray in both directions i.e. top and bottom after cleaning. This has 8 numbers airless spray film thickness of 25 microns can be achieved. The treatment line is also provided with the pre heater before shot blasting and drying chambers after painting.Painting is done to avoid corrosion of plates. Using two nozzles on the top and two on the bottom, spray painting is done. Paint to the nozzle is supplied by the pump. There are two pumps one will supply paint to the top nozzle and the other will supply to the bottom nozzle. The paint used is zinc rich prime (costlier, long life, 9-12 months), zinc silicate primer (cheap, short life, six months).
The hull shop consists of Gas Cutting Machines Hydraulic press Plate and Structural Rolls Machine EOT Cranes
CONCLUSION: Plates coming from the steel complex [assed to hull shop through automatic system by using sensors in conveyor rollers. The plates are processed and they are transferred to the fabrication department for the making of panels and frames etc…. Generally Hull shop acts as the BACKBONE OF SHIPYARD. SUB-ASSEMBLY & ASSEMBLYFabrication is the primary stage of work. The material that is processed in the bays of the hull
shop is transported with help of EOT cranes to the prefabrication chamber. Initially the elemental
sections that are being transported are marked individually, these marked products are segregated
according to the marking and they are kept aside. Now using different EOT cranes these parts are
supported so that welding can be done upon them so that these panels can be together as a
complete ship panel.
The shaped and cut sheets from the hull shop are obtained by this
division and sub-assemblies are done for a desired panel. Further all these sub-assemblies are
combined together and are aligned together according to the panel drawings. Quality checks
and surveys are done at each stage to ensure good quality and integrity of the sub-assemblies
and assemblies. After getting clearance for full welding (i.e., after fit up survey) the assemblies
are welded together and again are inspected for integrity surfaces. Advanced outfitting is also
performed after this process. In pre-fabrication department small sections and sometimes block
will be constructed as per the working drawings (WDS) issued by drawing office (through PP &
PM). The real construction works starts here only. In pre-fabrication department the major
work is drawing related welding process and other joining process after construction of small
sections in term big panels shifted to erection department sometimes to ships birth will be
done. In pre-fabrication shifting of completed blocks can be done with overhead sliding crane in
assistance with “KMAG” trailers.
The term sub assembly means the assembling of different elements of the
panel for main assembly stage, usually to high state of completion. These can be described into
two groups such as large sub-assemblies and light sub-assemblies.
1. Large sub-assemblies:
Fore peak units
After peak units
Bulk heads etc.
2. Light sub-assemblies:
Accommodation bulk heads etc.
Advantages of the sub assembly method:
Allocation of work on over hanging staging.
Welds normally over head or horizontal may be made in the down hand or vertical
position giving increased speed of welding and better quality.
Easy access obtained to sub parts as could bottom, fore peak, cruiser stern etc.
Work on the units can be commenced and progress before the ship would normally be
ready for such work.
Welding in sub assembly: There are four processes which are being followed in CSL, they are as
3. Manual arc welding
In the sub-assemblies, plates are generally laid on skids and plate ends are clamped or
dogged down to skids after setting to the correct position to prevent distortion, generally
without interfering with shrinkage.
The process of construction and assembling of panels in the building dock or building berth is called as erection. Usually pre-fabrication is followed by erection.
Steps involved in erection process
1) Preparation of berth/ building dock2) Marking of reference lines3) Placement of blocks4) Erection of panels5) Alignment of panels6) Consolidation7) Survey
Before welding edge preparation is done for proper welding.In welding, panels are welded together.The following are the erection sequences of the general cargo ship.
Double bottom port Double bottom starboard Transverse bulkhead Side shell Bilge plates Tween deck sides Tween deck centre Main deck sides Main deck centre Main deck hatch
OUTFITTING3 TYPES OF OUTFITTING METHODS
• UNIT OUTFITTING• ON-BLOCK OUTFITTING• ON-BOARD OUTFITTING
ON-BLOCK OUTFITTINGOutfitting carried out during fabrication of hull blocks. ON-BOARD OUTFITTINGOutfitting work carried out to complete the outfitting works after erection of hull block in dock. UNIT OUTFITTING Unit outfitting are modules which can be assembled separately in workshop skids and are independent of block construction. Unit outfitting is carried to reduce the On-board outfitting works. Efficiency of unit outfitting is almost 5 times as that of on-block outfitting is term of man-hours Necessity to divide outfitting works into smaller Modules
Lack of material OR too many material supplied at a time shall lead to production delay. Hence it is necessary to DIVIDE the outfitting work in suitable LOTS by the
STAGE and ZONE into on-unit, on-block, and on-board modules. Consequently, it is required that the FITTING DRAWINGS and their MATERIAL
LISTS (MLF’S) are separated in accordance with the STAGE and ZONE work packages (Modules).Material Control During OutfittingThe most important thing for outfitting work is that the“Only Necessary Quantity” of the “Correct Materials” be supplied to the “Required place” at the “Right Time”MLF - Material List of FittingsMLF is a list of all outfit components required for a particular stage/zone outfitting.TYPES OF MLF
UNIT MLF BLOCK MLF ON-BOARD MLF
BLOCK MLFBlock mlf contains items which can be fitted in block stage like manholes, hatches, ladders, equipment seats, anodes, gratings, cable trays, pipe pieces vent ducts, supports, penetration pieces, valves etc.
PALLETISATION Process of grouping Outfitting materials required for a particular stage/zone outfitting as per the respective MLF is called Palletisation.
The repair dock of 270 x 45 x 12 M can accommodate ships up to 1,25,000 DWT. The dock has high capacity discharge pumps to drain it in less than three hours. It is served by three LLTT cranes, one of 40 T and two 10T capacity.
There are three quays of 280 M length with 15 T cranage, 208 M length with 10 T & 5 T crane and 460 M length with 20 T crane. The quays have adequate service lines of oxygen, acetylene, compressed air and power connections.
Engine and Machine Shop
This shop is equipped with modern machine tools like Plano miller (up to 30 T) Bar Boring equipment (up to 300 mm dia), Inside Grinding machine (up to 300 mm dia), Heavy Duty Lathes (up to 12M length), Horizontal Drilling machine ( up to 100 mm boring & 600 mm drilling), Shrinkage equipment (up to 6 M x 900 mm O.D), Cylindrical Grinding machine (630 mm dia x 2 T), Horizontal Boring machine (up to 560 mm dia), Dynamic Balancing machine (up to 3 T) etc.
Hauling Carriage for safe docking and un-docking of ships. High Pressure Water Jet for hull cleaning. Blasting and Painting of conventional, epoxy and SPC systems. Facility for Boiler re-tubing. Facility for Tank Coating. Electric shop for overhauling of motors and testing. Electric power at 50 Hz & 60 Hz. Pipeline supply of compressed air, oxygen and acetylene.
Some major repair projects
Major upgradation of Mobile Offshore Drilling Unit ‘Sagar Vijay’ of ONGC. The upgradation increased the drilling capacity of the vessel from 300 M to 900 M
Maintenance and repairs to the Aircraft Carrier “ INS Viraat” of Indian Navy Repair and maintenance of tankers and bulk carriers of Shipping Corporation of India.
IHOPINTEGRATED HULL CONSTRUCTION, OUTFITTING AND PAINTING
IHOP System is a integration of Block construction with Zone outfitting method and Zone painting method.
Zone outfitting method: A shipbuilding system which organizes outfitting work by zone and stage into on-unit, on-block, and on-board work.
Zone painting method: A shipbuilding system which integrates surface preparation and Painting work into the overall construction process.
*IHOP construction is aimed at minimizing the work in dock so as to reduce the over all construction period.
*Efforts for IHOP construction should begin right from the start of Design work.
Hull Outfit Desig
Accommodation Outfit Design
Machinery Outfit Desig
Ship Design process can be
considered to be completed in three
Carried out by Forward Design & MarketingCarried out by Design Department
Basic design mainly includes the preparation of the following Drawings /Documents.
Hull surface model
Mid ship section
Hydrostatic, capacity, stability & maneuvering calculations
Functional design includes the preparation of following drawings / documents, most of which calls for owner / class approvals
Hull structure key plans Scantling Calculations Access arrangements
Mooring arrangement planLSA / FFA and L&SS planVentilation & Piping diagramsWiring diagramsMachinery arrangement
Propulsion systemAccommodation planPainting schemePurchase order specifications, etc
Typical Design Process and Production flow of outfitting work
tl s D
On Board(Building Dock)
Fr O O
Fab DwgPipe piece
MLPFab DwgPipe Supp
Fab DwgVent Duct
Fab DwgGrate Ladd
Conclusion: It has been learning experience us in the past one month. The various steps involved in ship building had been studied. We gained a lot of practical experience. From the initial processing of steel to the final process of delivery it involves many stages to pass through. Study of various process involved in Hull Shop like marking, cutting, bending etc., is done. Similarly various processes in pre-fabrication department sub-assembly, main assembly of various types of vessels can be done. All of those processes had been learnt and seen practically. Finally to conclude it had been a wonderful gaining learning thought provoking experience for us.