Ship Construction
Stages of Ship Construction
1.) Gathering, mobilization and sorting of materials Materials are arranged in such a way that the last that was being filed up on top is the first material to be cut. It is sorted according to thickness plate, size of bulb flats, angle bars, etc.
2.) Cutting of materials – now a day’s materials are cut by CNC machining, draftsman from the Engineering or Design section of the Shipyard will provide stl or jpeg file drawings, they saved it in a floppy disk or portable USD flash disk. This is being inserted on the CNC machine computer control board then the machine will cut according to shape of the detailed drawing.
3.) Fabrication will start from the basic component of the Ship “the Panel”, during this stage this is called the “Panel wise fabrication”. Plate is being joined together in a horizontal level ground for straight panels, pin jigs are being used to support curved panels wherein not all surface is tangent to the level ground. Plate is being joined by submerged arc welding. There are horizontal or vertical members that are being fitting during this stage; these are the girders and stiffeners. Girders are the rigid frame of the ship whiles stiffeners are the sub-members in between girders or frame. During this stage panels are fabricated in either of the following part of the ship; main deck transverse bulkhead, longitudinal bulkhead, side shell, inner bottom or tank top and bottom shell.
4.) Panels are now joined together to form a block inside a graving dock or floating dock – a ship is subdivided according to several blocks in either of the following blocks; fore peak tank, side ballast tanks, center cargo hold compartment, engine room, after peak tank and accommodation block. Blocks are joined by welding a ceramic filled welding in an FCAW process (Flux Cored Arc Welding). Each and every stage of Ship Construction there are frequent inspection of a trained Quality Assurance personnel that are knowledgeable in Steel fabrication, welding, NDT and well verse to the standard criteria of Classification Society like IACS (International Association of Classification Societies) Inspection records are maintained through all stages in each fitter’s traceability, welder’s traceability, dimension traceability, NDT (non-destructive testing) traceability and material traceability.
5.) Careful planning and execution of schedules are made in each stages to ensure that there’s no component that are left behind, we cannot cut the ship’s compartment again to install the left behind valves, pipe parts, pumps, etc.
6.) There are several departments involved in Ship building; Hull – which is the structural department, pipe, outfitting - for the non-structural components of hull such as manhole, hatch cover, bobby hatch, railings, tank supports etc. machinery department for auxiliary engine, main engine, reduction gear, governor, heat exchanger, etc.