Industrial Training Report Cochin Shipyard Limited
Sanjay Suresh B.Tech (Mechanical) VIT University Chennai Campus
Acknowledgements For the two weeks I spent in Cochin Shipyard Limited, I have many people to thank. Firstly, I would like to offer my sincere gratitude to Mr. Ramadas M P (Deputy Manager Training) for providing me this opportunity for In-plant Training in CSL. Next, I would like to thank all the department heads and their secretaries for scheduling our daily training and ensuring a smooth learning experience. Every moment I spent in Cochin Shipyard Limited, I felt as if I was part of a big family. Every individual from trainees to the supervisors were more than helpful in answering all our queries and in helping us in any way possible. So finally, I would like to thank all the CSL staff for their unconditional guidance and helpful nature which made this Training period into one that I will always cherish.
Introduction The training in Cochin Shipyard Limited focused on three major departments i.e. ship building, ship repair and utilities & maintenances. The schedule was well prepared with equal number of days in each department, so as to give equal importance to them. Safety equipment such as safety helmets and safety boots along with uniform was directed to be worn throughout the duration of the training. Extending for a period of 15 days, the aim of the training is to give each student thorough knowledge about the different departments of Cochin Shipyard Limited and for them to fully understand it's working.
Ship Building Hull Shop The ship building process can mainly be divided into 7 continuous steps. The work is started after acquiring the necessary inputs like the nesting plans, stiffener arrangement program and various other design inputs. Accordingly the whole of Hull shop is divided into different bays dedicated to some part of the whole process. Preservation is done by acquiring the metal sheets and storing them in the yard. This should be done in the appropriate conditions. The process of preservation begins with straightening the metal sheets using rollers. This machine is termed as a mangling machine. The sheets are placed on a conveyor belt which feeds the sheets to the machine. The machine is set according to the thickness of the sheets. The sheets are then rolled and pressed to ensure they are flat. The sheets are then carried to an abrasive or shot blasting machine by the conveyor belt for blasting the sheet. Blasting is done to ensure that the surface of the sheet is cleared and is free from any sort of impure coating, rust etc. The sheet after being blasted with abrasives, comes out clean from all such rust. It then moves immediately to a priming machine. A zinc primer is used by the machine to give the sheet a protective coating which will then serve as a layer of protection for the sheet. Not only that, priming is done as a preparatory coat to painting which will be done in the later stages. Priming is done on both sides of the sheet at the same time. The sheet is then immediately taken to a drying chamber. In the drying chamber the primer is dried using hot air and the sheet comes out ready to be machined.
Preservation Preparation Forming Sub Assembly Assembly Grand Assembly Hull Erection
The sheet is then picked up by a crane and placed on a different bay area. This is where preparation starts. The sheet is then cut in various ways. One of the methods used to simultaneously cut and mark the sheets is a CNC gas cutter. Once the program is fed into the system by the design team, the gas cutter makes the necessary cuts. Another method is a CNC plasma cutter. Plasma cutting is preferred over gas cutting because of precision effects and cos of the quality of edge after the cut. It becomes easier to join these pieces now since they can be easily welded together. The last method of cutting is using a parallel cutter. Secondary cutting is done using shear cutter, where thinner sheets are cut by shearing them. The sheets after being cut are moved to bending machines. From here the forming process starts. Here the machine bends the sheet according to the profile required. The sheets are fixed to bending machines and load is applied in the area where the bend or curvature is necessary. Cranes are also used for the bending process to pull the sheet upward and make an upward bend. Or cranes are used as supports. Wooden templates are prepared to check if the curvature or angle is exact and compatible. Squeezing is also a forming
process. After these continuous processes of preparation, the sheets are taken to sub assembly. In subassembly, the sheets are joined to the stiffeners using welding techniques. Hence, small units are made and these small units are then moved to the next bay area for assembly. In assembly small units made in the subassembly are joined together to make a section of the ship. These sections would be pre-planned and designed by the design engineers and instructions would have been given on assembling it. These small units are joined together while being placed on structures called skids. The units are hoisted into place using cranes and the size of the units are limited by the capacity of the cranes.
Grand Assembly and Hull Erection The difference between grand assembly and assembly is that in grand assembly larger units of sections are joined to form bigger sections of large ships. These units are usually sections in themselves. They are joined together using welding, which is usually MIG welding. We saw a section of the front part of the IAC being prepared in the GA. The ski jump is to be fixed to this section and together they will be fixed to the front of the ship. In Hull erection, these sections from the GA are fixed together or welded in place. This is usually done in an area called the dry dock. The dry dock is usually at a depth below sea level and close to a water body. This is done in such a way that when the ship is ready to be launched, the dry-dock is filled with water, the gates are opened and the ship can be easily pulled outside. The IAC was being built in the building dock. The IAC is 260 m long and 60 m tall. It has two propellers and has a gas turbine propulsion. Currently, only the pins supporting the propeller shafts have been fixed. The IAC has 2 engine rooms in case one of them is destroyed in battle. It is understood that the HE of the IAC is 50% complete while only 10% of outfitting has been done. An estimate of 2 more years is required for the completion of the IAC. Since the current dry dock is congested with nearby cranes, the runway and the starboard extensions cannot be completed. Hence, the IAC is being moved to a new dry dock soon. For this purpose, two barges are being built on the front and back to balance the ship and move it into the other dock. HE is done with the help of multiple cranes, all of which can move along designated tracks which have been permanently placed beside the ship. These cranes are used to load and unload heavy units and machinery into the ship. The sections are welded together from the insides using MIG welding. Handheld grinders are used to remove the barnacles which attach themselves on to the exterior of the hull. After the above processes are completed, a major share of ship building is done. Once this metallic structure is completed, outfitting is started.
Outfitting Outfitting can be briefly explained as the fitting of all the machinery, inner works and everything that makes up a ship other than the main hull steel structure. Hence the outfitting department plays a key role in ship building. A ship cannot be completed without the outfitting process being completed. Pipes contribute to many of the major processes that takes place during the running of a ship. Everything from the supply of fuel, coolant, oil, water, air etc is done with the help of pipes. For this complex network of pipes to be fabricated and installed, the pipe shop and its workers are put to use. The fabrication begins with the process of preparing the pipes. This is done pickling the pipes in solutions made specifically to enhance properties of strength, resistance to corrosion etc. After the preparation process for pipes, its cut into the desired lengths. This is mostly done using CNC cutter which supports both gas and plasma cutting. For gas cutting oxygen and acetylene are used. The pipe is cut automatically only after manually feeding in the data such as starting position, outer diameter, inner diameter, angles such as beta, gamma and chi, S (Denoted for carriage feed), etc. Plasma cutting is used for non ferrous pipes while ferrous pipes are cut using gas cutting techniques. A secondary cutting technique of abrasive cutting is also used. This is mainly used to cut off unwanted parts of the pipe after it has been subjected to the bending machine. After cutting, the pipes are bent using bending machines. There are 4 different bending machines in the pipe shop for pipes of various diameters. Some of them are digitally controlled. The dies on the bending machines are removable and the appropriate die can be fixed with respect to the outer diameter. An object called mandrel is used to ensure that the bent surface is smooth and the pipe is not crushed. The pipes after being bent to the necessary angles are sent to the fabrication section of the pipe shop. In this section, they observe the design provided to them by the design team and they perform minor tack welding and sends the pipes to the welding section of the pipe shop. In the welding section, various welding techniques are used to make the necessary pipe arrangements. TIG welding is used while welding alloys. Otherwise, MIG welding is preferred. TIG welding has a better weld quality and lesser slag formation. After the pipes are welded, they are sent for testing. A team conducts various levels of tests on these pipes and approves them for use in ships and sends it back to the pipe shop. Once the pipe shop receives the pipes that are fit to be installed, they are sent to the palletisation section. Here the pipes are sorted according to various parameters such as where they are usually used and which kind of vessel they are used on. After being sorted, the pipes are taken by the various teams working on ship building as and when they are necessary.
Sheet metal is also excessively used in outfitting in ships just like pipes. In the sheet metal shop, small sheet metal units are made which are later welded together to make the desired unit. Shear cutter is used to cut large sheets of sheet metal into the desired sizes. Small sheet metal structures are used as supports for pipes and other elements in the ship.
Ship Building Outsourcing Cell The ship building outsourcing cell or commonly called the SBOC heads all the activities of outsourcing work of CSL to other companies. Sometimes, due to the nature of work involved or due to shortage of staff, CSL finds it more feasible to outsource the work. If the materials for the work to be outsourced are provided by CSL, SBOC takes care of the whole process. If otherwise, the materials are not provided by CSL, the Materials department takes care of outsourcing. Outsourcing in SBOC is mainly done in two ways. The first is when SBOC decided the rate of the job to be completed and invite registered agencies to do the job and the second is by floating tenders. Tenders are primarily divided into three. In limited tenders, only the agencies registered with CSL will be invited to do the work. In online tender method, the tender will be released to all via the online website. And finally, in open tender method, the tender is released to all and published in a few reputed newspapers. Tenders include various kinds of clauses to which both parties have to agree to. They also include certain guarantees. EMD or Earnest Money Deposit is the money the agency has to pay CSL if they pull out before the winner of the tender process is decided. Safety Deposit is the money that they agency will lose if they don't complete the work in the stipulated time. And finally, Performance Guarantee will extend for over a year after the work is completed and is an assurance for the quality of work done.
Services and Co-ordination
Services and co-ordination department or the S & C department provide major services which plays a major part in linking the various other departments of ship building. The department fabricates and installs various small structures which are vital to other departments such as small bridges, pales, scaffolding, etc. The Central Tools Crib or CTC is run by this department and is the hub for issuing boots, coats, hats and tools used in the fabrication processes such as consumable electrodes, hammer, nails etc. A Material List of Fittings or MLF is used to keep track of what is required and vouchers are used to issue the items.
Utilities and Maintenance For the processes of ship building and repairing to go about smoothly, they require the help and upkeep services offered by Utilities and Maintenance department. They are responsible, on a very basic level, for providing consumables to all the departments and for maintaining the machines in the various departments of CSL.
Objectives The main objectives of the U & M department are: 1. Upkeep of machinery in the various departments in CSL 2. Acting as a Liaison for CSL and conducting statutory tests 3. Providing utilities like consumables, electricity, transport etc.
Activities The various activities of the U & M department included -: Activity
Remarks
Maintenance of machinery, cranes, machine tools, portable equipments, small tools and welding sets
Preventive Maintenance Breakdown Maintenance Planned Maintenance
Procurement and storage
Spare Parts Consumables
Supply of Consumables
Power Supply
Substations Main Receiving Station
Oxygen Mixed Gas Nitrogen Acetylene Carbon Dioxide LPG Water
Transportation
Communication Office Facilities
Mobile Cranes Fork Lifts Trucks and light vehicles Telephone Exchange PA System Air Conditioning Water Coolers
Statutory Testing
Cranes, lifting tools, Pressure vessels and boilers
Liaison work with Statutory Bodies
KSEB Pollution Control Board RTO Office
Energy conservation
Energy Audit Energy Management
Building Maintenance
Electrical Civil
Dock Operations The machine maintenance department in the building dock is named MM1 and the one in the repair dock is called MM2. All the machines are periodically checked and maintained by this department. In case of an emergency breakdown, they provide immediate assistance. MM2 is also responsible for the maintenances of the Gantrys in the building dock. There are a total of 7 large cranes including the LLTTs (Left Level Travelling Tower) and Gantrys and a sum total of 24 cranes including the smaller EOTs (Electronic Overhead Traveller) as well. The machines in the pump room is also maintained by U & M department. The pump room in the repair dock houses the gate winch, which is connected to chains, gear drive and finally the gate. The gear drive is used to decrease the speed of the motor. There is a capstan next to the gat winch, which is used for pulling in the ship in a straight line. The main discharge pump housed in the pump room removes water at the rate of 4420 litres per second. The water is removed through the grills placed in the bottom of the repair dock. When the ship is to be docked in the repair dock, it is dragged inside using the capstan and aligned with the blocks which would have been already placed according to the layout of the hull of the ships. Once they are aligned, the water is slowly pumped out and the ship is fixed in the dry dock.
Compressor Shop The compressor shop houses the compressors responsible for providing compressed air for the entire shipyard. This compressed air is used for blasting purposes or it is used for pneumatic tools. Either ways, the compressed air requirement is very large in CSL and hence the compressor shop is vital. Out of the 6 air compressors in the shop, 2 are rotary compressors and 4 are reciprocating compressors. Rotary compressors use larger power and give higher outputs. They have a large suction mouth through which air is sucked in and passed through filters. These filters have to be regularly cleaned and even replaced after a while. Rotary compressors have 3 stage compression process with the availability of inter cooling between each stage and an after cooler at the end of the compression process. The advantage of a rotary compressor is that the number of moving parts are less. The disadvantage is that it cannot give a reduced output and if output is reduced below a point, it shuts down automatically. A bypass valve is introduced to a rotary compressors to release excess air so as to get a reduced output. But the problem is that the input does not change and hence power is wasted. Reciprocating compressors are commonly used for daily purposes in the compressor shop. These compressors are double acting and are water cooled compressors. They also have oil cooling using jets for the smaller moving parts. The reciprocating compressor uses a two stage compressing process. The output of the compressor can be reduced by using valves and by loading these valves wither manually or automatically. It is automatically done using the help of various sensors places in the compressor and storage tank. Water that is used for cooling is air cooled outside the compressor shop and is then fed to a tank from which it is again sucked in for cooling purposes.
Transport The transport section of the U & M department helps with material movement as well as movement for people around the shipyard area. Most of the important machines for material movement used in the shipyard are housed in the transport section. These vehicles include mobile cranes which have capacities up to 150 tonnes, forklifts with various capacities such as 5, 10 and 20 tonnes and other vehicles such as the one usedto carry sections of the ships which can support up to 100 tonnes and a vehicle to raise a worker to high locations using a hydraulic arm. All these machines are maintained and run by the department and the smooth operation of various departments depend on this.
Ship Repair Just like ship building, ship repair is one major department in CSL. Over the year, dozens of ships are docked in CSL for repair related work. As ships run for more than 2 years at a stretch in the highly corrosive salt water, it is mandatory that they will require various repair work. For the continuous running of ships, the permit from certain authorised surveyors are necessary. For this purpose, ships are docked in CSL, repaired and then surveyed. The survey is conducted in a proper fashion by authorised surveyors like ABS or IRS. After getting their approval, the ship is ready to disembark and can run without any major repairs for a while. The repair dock used for ship repair has the dimensions of 270X45X12 m. It is filled with water using a valve system and the gates of the dry docks collapse backwards to provide entry for the ships. If a ships in one half of the dry dock are to be released without disturbing the work going on in the other half of the repair dock, then a damming wall kind of surface is placed between the two halves. This is to ensure that the water does not go into the area where work is still being completed.
Hull Repair Before starting repair, the ship is gauged using a gauging mechanism like an ultrasonic mechanism. Using the parts of the hull where material has corroded away to a high extent is noted. These plates are marked and they are cut away using gas cutting. Gas cutting is done by using oxygen and acetylene. They are then replaced with new metal sheets which are bent to the required profile of the cut sheet. They are replaced in such a way that the stiffer arrangement is not disturbed and least amount of welding seams are made. This is hull repair and a major part of the repair activities in the repair dock is hull repair. If the sheets don't need to be replaced but if they do have a coating of rust or other deposits on its surface, shot blasting is done to clean the surface. Compressed air is provided to the repair dock, which along with metallic shots are used for blasting. There are also machines which use water instead of air. Handheld grinders are also used to clean certain areas of the hull.
Pipe Shop There is a pipe shop adjacent to the repair dock which facilitates the refurbishing of the pipe systems in the ships which have been brought for repair. Most of the pipes in ships which have been running for a while would be rusted and corroded. These pipes are usually replaced with new pipes upon the request of the owner of the ship. One team works on the ship, removing the pipes etc and another works in the shop making identical pipe arrangements with brand new pipes or by place new pipes in certain parts of an existing pipe network.
Currently all the latest ships are installed with cupro-nickels pipes for carying sea water as they have high anti rusting properties. Otherwise, mild steel pipes are used inside the ship. High pressure pipes are made by extrusion process and not welding. They are called seamless pipes. After these pipes are assembled according to the required design, they are tested by using various methods. Then they are flushed using a flushing machine and flushing oil for several hours to remove the scales and other sediments in the inner walls of the pipes before they are installed in ships.
Machine Repair The machine repair shop is alongside MM2 and caters to repairing the machines that are used in a ship. It often happens that a part of the machinery of the ship, i.e. a part other than the hull, has under gone wear or it is not working in full capacity. In such a case, the part is removed from the ship and brought to the machine repair shop where the machinery is repaired. The propellers, shafts, rudder etc is brought here to be refurbished and is then returned to the ship. Before it is reassembled in the ship, all the machinery have to undergo certain tests. This is to ensure the strength of the parts and their durability, etc. Then, a survey team verify that all the machinery are sea worthy and only then is it installed on the ships.
Conclusion My 15 day training in Cochin Shipyard Limited has been an educative experience like no other. To see what we have read only in textbooks in front of our own eyes is a different feelings. It helps us understand far better than we ever could by reading a book. I have understood the processes involved in making a glorious ship from just sheets of metal. I have witnessed each and every process personally and understood the necessity of each step in the chain of events. Moreover, I have understood how an industry functions and how man, machine and material can combine to produce effective products.
