Training In Hull Shop And Shipbuilding Shop

Training in Hull Shop and Shipbuilding Shop The work in modern hull shop is mainly comprised of construction of blocks, from plates, and attaching longitudinal and transverse stiffeners. This is accomplished mainly by welding. The blocks can be the various positions for the ship, namely superstructures, bulkheads in the midship, and fore and aft regions. After the construction of these blocks, they are transported to the dry dock with the help of cranes. The Crane Capacity available for Fabrication Shop-50 MT, Machine Shop-75 MT and for assembly Shop-100 MT. Bottom Structure: The centre line of the bottom structure is located on the keel. The commonest form of keel is the flat plate keel, which is being fitted in the ship.

When grounding is required, this type of keel is suitable with its massive scantlings, but there is problem of the increased draft with no additional cargo capacity. If a double bottom is fitted the keel is almost inevitably of the flat plate type, bar keels often being associated with open floors, where the plate keel may also be fitted. Double Bottom Structure: Double bottoms may be framed longitudinally or transversely, but since the ship’s length exceeds 120 mts it is considered desirable to adopt longitudinal framing.

Floors: Vertical transverse plate floors are provided both where the bottom is transversely and longitudinally framed. At the ends of bottom tank spaces and under the main bulkheads, watertight or oil tight plate floors are provided. These are made watertight or oil tight by closing any holes in the plate floor and welding collars around any members which pass through the floors. Elsewhere ‘solid plate floors’ are fitted to strengthen the bottom transversely and support the inner bottom. These run transversely from the continuous centre girder to the bilge, and manholes provided for access through the tanks and lightening holes are cut in each solid plate floor. Also, small air and drain holes may be drilled at the top and bottom respectively of the solid plate floors in the tank spaces. The spacing of the solid plate floors varies according to the loads supported and local stresses experienced.

Majority of these tasks are accomplished by welding and cutting. Mainly Gas Metal Arc Welding is used in the process. A wire or electrode is connected to a source of electric supply with a return lead to the plates to be welded. If the electrode is brought into contact with the plates and electric current flows in the circuit. By removing the electrode a short distance from the plate, so that the electric current is able to jump the gap, a high temperature electrical arc is created. This will melt the plate edges and the end of the electrode if this is of the consumable type. Electric power sources vary DC generators or rectifiers with variable or constant voltage characteristics being available as well as AC transformers with variable voltage characteristics for single or multiple operations. The latter are most commonly used in shipbuilding. In manual welding electrodes, the core wire normally used for mild steel electrodes is rimming steel. This is ideal for wire drawing purposes, and elements used to ‘kill’ steel such as silicon or aluminum tend to destabilize the arc, making ‘killed’ steels unsuitable. Coatings for the electrodes normally consist of a mixture of mineral silicates, oxides, fluorides, carbonates, hydrocarbons, and powdered metal alloys plus a liquid binder. After mixing, the coating is then extruded onto the core wire and the finished electrodes are dried in batches in ovens.