Text 3b

NAVIGATING A SHIP

When a large ship leaves port, three or four small tugboats pull it from the pier into the harbour. A docking pilot directs the tugs and the ship until the vessel clears the pier and is underway in the harbour. The tugs then leave the ship and the docking pilot turns the vessel over to a harbour pilot. Every mer­chant ship enters and leaves port with a local harbour pilot aboard.

The harbour pilot guides the ship into the harbour or out into open water. The harbour pilot must know every channel, turn, sand bar, or other obstacle that could endanger the vessel. After a ship reaches open sea, a small boat comes out and carries the pilot back to port. The ship officers then navigate the vessel to its destination.

On the bridge, the navigator, usually the second mate, uses various equipment to locate the ship's posi­tion. As sailors have done for thousands of years, the navigator checks the position by observing the sun, moon, planets, and stars. For hundreds of years, the most important navigation devices have included a com­pass to tell direction, a chronometer to tell the exact time and help to determine a ship's longitude, and a sextant to calculate a ship's latitude by measuring the angle of the sun or of a star above the horizon.

Modern ships also have highly accurate electronic navigation equipment. Many ships have devices for de­termining their position through radio signals. These signals are sent out continuously by special transmitting stations along the coasts of busy trade routes. One such system is called loran, for long-range navigation. With loran, an accurate position can be obtained in bad weather and poor visibility without a compass, chro­nometer, or sextant. Many ships also can determine their position by signals that are transmitted from orbiting satellites.

Modern ships also carry radar. At night and in bad weather, a ship's radar can spot icebergs, rocks, and other vessels in time to prevent a collision. Some modern ships also have an automatic pilot, which, after a ship has been set on course, holds it there. This device is linked to gyrocompass, which determines direction, and it operates the rudder automatically. In spite of all these remarkable devices, navigators still also use the tried-and-true compass, chronometer, and sextant.

Automation aboard ships is increasing, but no ship is as yet completely automated. Most automation has been in the engine room. When the officer on the bridge signals the engines to go ahead or backward or to change speed, the engineer no longer has to make adjustments by hand. Instead, the engines respond immediately. The operation of the valves and the necessary change in temperature or pressure are taken care of au­tomatically. Many ships have automatic navigation aids and automatic devices to speed up the loading and un­loading of cargo. Automation may one day make it possible for cargo ships to have only 9 or 10 crewmen.

Ex. 13. Answer the questions:

1. What is the procedure of port leaving? 2. What is the difference between the work of docking and harbour pilots? 3. What equipment is traditionally used for navigation? 4. Who usually fulfill the duties of navigator on the bridge? 5. How can modern ships determine their position? 6. What is the loran system? 7. Are modern ships completely automated? 8. What are the advantages of automation in the engine room?

Ex. 14. Explain why:

1. every merchant ship enters and leaves port with a local harbour pilot aboard;

2. the most important navigation devices haven’t been changed for hundreds of years;

3. radar is connected with the gyrocompass and the rudder;

4. it is possible for cargo ships to have only 9 or 10 crewmen nowadays.

Ex. 15. Develop the idea:

1. The piloting work is vital for the shipping;

2. The principles of modern navigation resemble those of the Middle Ages;

3. Accurate electronic equipment facilitates the navigation;

4. Automation aboard ships is increasing.

Ex. 16. Skim the text and make up a short summary.