Text 5a

CONSTRUCTING A SHIP

A ship is one of the most complicated objects ever made. It is actually a floating city that generates its own power, heat, and electricity. A ship carries her own fuel and provisions. It can make her own fresh water from the sea, and she disposes of her own garbage.

All ships have four main parts: (1) the hull, (2) the engines, (3) the propellers, and (4) the rudder. In designing a ship, naval architects plan these and other parts of the vessel so that it meets a shipping company's special needs as well as government safety regulations. A shipyard then builds the ship according to the architect's plans.

Before naval architects begin to design a ship for a shipping company, they must know how the firm plans to use the ves­sel. They must know where the ship will sail, what kind of cargo it will carry, and how fast it will have to travel. Architects also must be aware of government safety regulations. In addition, they must adjust their designs to allow for the ever-increasing use of automation on ships.

The shipyard carefully follows the architect's designs in building a ship. Traditionally, construction begins with the laying of the keel. Workers then build the ribs that support the hull and give it shape. Next, they weld the metal plates that form the middle section of the hull. As the middle section is built, the various compart­ments, the boilers, and the necessary machinery are added. Finally, the bow and stern are built, completing the hull.

Modern shipyards no longer construct ships in this piece-by-piece manner. Instead, they first build enor­mous prefabricated sections of the ship in subassembly shops. Many of these sections have some wiring and piping built into them. Giant cranes then carry these huge sections to a framework called a shipway, where they are welded together. There is no laying of the keel. As the double-bottom sections of the hull are welded together, the keel is laid automatically. The entire hull may consist of as few as 20 prefabricated units. After the hull is completed, parts of the superstructure are added. The ship is then ready to be launched.

Shipbuilders launch a ship after it is about 70 to 90 percent com­pleted. The ship is slid down a runway of heavily greased timbers into the water. Most ships are launched stern first. A ship being launched bow first would plow down into the mud. Ships built along rivers too narrow for stern launching are launched sideways. Some yards build their ships in dry docks below the water level. After the hull and superstructure have been completed, workers open the valves and flood the dock. The ship then gently floats off the blocks that support the bottom of the hull. After the water inside the dock reaches the level of the water outside it, the dock gate is opened and the ship is launched.

Just before a ship is launched, it is christened. The shipping company selects a person, usually a woman, as the ship's sponsor. This person names the vessel and breaks a bottle of champagne across its bow. At that in­stant, the ship begins to slide into the water.

After a ship has been launched, a tug pulls it to an outfitting pier. There, workers complete the superstruc­ture and add the interior furnishings. The ship then makes its builder's trials with observers aboard from the company that ordered the ship. They make sure that all the equipment is in good working order and that the ship performs maneuvering, speed, and other tests ac­cording to the specifications. If the ship returns from the trials with a broom tied to the mainmast, it has made a "clean sweep" of its tests and the shipping company has accepted delivery of the vessel.

Ex. 7. Answer the questions:

1. Why can we call the ship one of the most complicated objects ever made? 2. What are the main parts of a ship? 3. What is the first step in ship designing? 4. What from does the construction traditionally begin? 5. What stages does the ship construction in piece-by-piece manner consist of? 6. How does the modern way of ship construction differ from the traditional method? 7. On what stage of construction is a ship launched? 8. Why are most ships launched stern first? 9. Where is sideway launching used? 10. What are the peculiarities of dry dock launching? 11. What is ship christening? 12. What does a broom tied to the mainmast mean?

Ex. 8. Try to summarize the main facts from the text in few sentences.

Revision

For Independent Studying

Ex. 9. Read the text and recollect the basic principles of shipbuilding in different historical epochs.