Text 4c

DREDGING

Dredging is performed in order to deepen water areas in harbours and shipping lanes and also to remove especially contaminated sediments. Dredging is carried out through digging, use of explosives or flushing of sediments. The dredged material is taken care of in different ways. Usually it is dumped into water but it may also be deposited on land or in an area surrounded by a seawall.

Dredging and dumping activities are common during the construction and maintenance of marinas. The dredging is normally small-scale and often concerns relatively clean sediments. Dredging and dumping activities on a larger scale are performed during upkeep and expansion of harbours for trade shipping. This dredging often concerns sediments with contaminated surface layers.

Substances that demand special attention are mercury, cadmium and PCB, but also nutrient and organic material. Other substances that can be important in this context include arsenic, zinc, copper, lead, nickel, chromium and oil. Pollutants can be found especially in areas that have received industrial discharges and in harbours.

Improperly managed dredging and dumping or disposal of dredged materials may cause a serious environmental contamination.

Ex. 18. Summarize the unit information and speak on the topic “Environmental Impact of Shipping”.

Unit V early history of shipbuilding

Ex. 1. Read and remember the words:

Plank, yacht, freighter, pillar, quarry, oar, frame, stern, keel, rib, hull, bow, shelter, galley, cabin, mast, bireme, rig, trireme, knot, waterline, ram, prow, harbor, dragonship, siding, shipment, cog, castle, rudder, galleon, skerry, sample, aft, blade, crest, sole, extremity;

To droop, to sag, to stiffen, to raid, to overlap, to dwell, to sustain, to complete, to grasp, to sweep, to exclude, to weaken;

Enormous, rectangular, sturdy, triangular, seafaring, bold, superb, clinker-built, lateen; sufficient, destructive;

Approximately, astern, nevertheless, consequently

Ex. 2. Insert the right word:

Galley, ram, astern, yachts, planks, mast, waterline, approximately, shelter, droop, hull, cabins, shipment, siding, castle, dragonships, bold, overlap, raided, superb, clinker-built, harbor.

1. The long ships with a head of a dragon on the bow were called the … 2. The way to the port will take you … half an hour. 3. The captain commanded full speed … to stop the ship. 4. The … of the boat is made of … fastened together. 5. Historically, a … is an ancient warship. 6. “Let’s find a … . Storm is coming!” 7. The passengers were pleased with service and comfortable … of the liner. 8. … are small sailing or motor boats for pleasure and sport. 9. The stormy wind was so heavy that the … with all sails began to … and fell by the board. 10. The ship hit over the … of an iceberg and got a hole under the … . 11. In the case when the planks of the ship … … one another, we say that the ship is … . 12. 4. The … Vikings often … the territory of Britain. 13. The … included the … spices from India. 14. The ship managed to find a … and survived the storm. 15. The … was called so, because its shape reminds the fortress tower.

Ex. 3. Change the words of italic type with their synonyms from your active