1. Deck; 2. Transverse bulkhead; 3. Side frame; 4. Stem; 5. Forepeak; 6. Side stringer; 7. Double bottom; 8. Floor; 9. Afterpeak; 10. Sternpost; 11. Hatch; 12. Carling; 13. Deck beam
The space between all these superstructures of the upper deck is usually protected by with bulwarks.
Subdivision members of the ship serve to provide unsinking of the ship, fire- proof safety and the strength of the ship. Subdivision members are accomplished with the arrangement of decks and partial decks and with the arrangement of transverse and longitudinal bulkheads. They make compartments of the two kinds: decks of the hull and decks of the superstructures. Decks of the hull are as follows: upper deck, middle deck, lower deck and platform.
The decks of superstructure are the following: bridge deck, lower promenade deck, upper promenade deck and boat deck.
Taking into consideration all this the hull construction of a modern vessel is composed of (1) longitudinal framework, keel, keelsons, stringers, deck girders, longitudinal bulkheads, hull and deck plating; and (2) transverse framework, beams, transverse bulkheads, wooden deck, etc.
As for the external shell plating and deck plating they also stiffen the hull transversely. At interconnections of longitudinals and transversals additional ties are introduced such as in the form of brackets and straps.
Rigidity stability and permanent depth of hull is guaranteed by floors, side plating longitudinal and transverse bulkheads as well as by pillars. Local rigidity at the ends of the hull is also secured by stem and stern.
There are different methods of hull shaping.
Pyramid method of building up hulls from prefabricated sections.
Pyramid method:I-V11—pyramid Nos.; the sections for pyramids I, III, V and VII are shaded
Building up the hull on the building berth starts with the assembly and welding of the first pyramid, with the sections in the subsequent pyramids butt-assembled to it. The entire hull is assembled and welded successively forward and astern from the centre of the prefabricated bottom section of the first pyramid, and to the sides and upwards.
The "island" method of building up the hull froт sections.
When this method is used, sections are simultaneously placed in position at two or three zones along the hull (for instance, at the midship, bow, and stern zones).
The “island” method: А, В and С—the stern, midship and bow islands; the sections for the initial pyramids in each island arc shown by the criss-cross shading
The difficulty of building a hull by this method lies in joining the islands together. If the islands are assembled on movable trolleys, they can be joined together by moving the trolleys. If the islands are assembled on keelblocks, connecting sections should be installed along the entire perimeter of the hull to join the islands together.
The block method of hull construction.
The block method: I-VI – hull blocks Nos., in the sequence of installing
In the block method the "blocks" (completed parts of the hull between sections parallel to the midship plane) are assembled from previously fabricated sections in which installation work has already been done. The finished blocks are despatched to the building berth, where they are butt-assembled; the installation work in the regions of the butt joints is then completed.
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