Modern Principles of Shipbuilding
Ships are extremely complicated engineering structures and high requirements are made of the materials and technological processes employed in ship construction.
In modern shipbuilding, the principal technological problems in constructing a ship are solved in the design stage. The materials and structure of the hull must satisfy the technological requirements. The following must be decided upon in advance: 1) the optimum subdivision of the hull into sections (or blocks); 2) the method of assembling the ship on the building berth; 3) the sequence in which the hull is to be assembled and welded in every stage of construction; 4) the extent to which sections (or blocks) should be completed before placing them in position on the building berth, so that the optimum amount of work is performed beforehand; 5) the combined sequence of hull and fitting operations; 6) the degree of completion of the ship before launching; 7) the amount and sequence of work left to be done after launching (afloat); 8) the economic advisability of using a particular technology for constructing a ship depending on the number of ships in the series.
The basic work of shipbuilding is performed in the 'following sequence: 1) the lines of the ship are laid-off (full size) to make the templates, patterns, etc.; 2) the hull components are marked off on the metal, or set out on template drawings; 3) the hull components are fabricated; 4) the flat elements are assembled and welded; 5) the flat and volumetric sections are assembled and welded, and the necessary installation work on them is done; 6) the sections are fitted up together on the building berth, the welds made, and the installation work in the region of the butt joints is done; 7) the structure is tested for leaks; 8) the ship is launched or floated out; 9) fitting out is performed afloat (the amount of this work should be reduced to a minimum); 10) delivery trials are performed.
At modern shipyards, lofting operations and the prefabrication of hull parts are done with the aid of computers and electronically controlled machines, which means improvement in the quality of the work done at every stage in the building of a ship, also reduction in work times, labour and costs.
Special technological offices are organized at shipyards for working out these technological processes. These specifications, which are also called the "technological processes", are despatched to the shops, which must comply with them. These documents must indicate all the operations in the technological process, the methods by which the work is to be done and the sequence for its performance, the jigs and tools to be used, the special training required by the workers, the labour required for operations, the time which they should take, and where they should be performed, also the basic delivery requirements. The technological processes must be agreed in advance with the technical staffs of the shops and design office, representatives from the purchasing organization, and the Technical Inspection Department of the shipyard. Once it has been approved, the technological process cannot even be partly altered by the shops unless this is agreed with the technological office and approved by the chief engineer.
1) Why are so high demands made to the process of construction a ship?
2) What must be decided at the preparation stage for optimal developing in production of a ship?
3) Is there any order of performance of a ship?
4) What improved the quality of the work done at every stage in the building of a ship?
5) What is meant under the term “technological process”?
6) What is organized at shipyards for working out technological process?
7) What do the documents produced by the technological office include?
8) Who must the technological processes be agreed with and approved by?
9) Can the technological process be changed by the shops in working order?
VOCABULARY
28. Practice saying the following words.