Intermediate english reading

6 | 
P a g e
 
Exhibition, the largest display of recovered artifacts from the ship, is on permanent 
display at the Luxor Hotel in Las Vegas, Nevada. In addition to more than 300 objects, 
the exhibit features stories of the passengers and a full-scale reproduction of the liner’s 
Grand Staircase. Other expeditions, a few of which are listed in the table below, have 
been more rewarding than the discovery of the Titanic. 
4
As adventure some as it may seem, the hunt for treasure ships has always faced 
major challenges. Until the 1950s, treasure hunters had difficulty locating shipwrecks 
that lay thousands of meters deep in dark and dangerous waters. At the turn of the 
century, failure often resulted from the hit-and-miss process of dragging wire nets and 
lines from two or more ships across the seafloor until they caught on something. In 
1918, the joint English-French Anti-Submarine Detection Investigation Committee 
(ASDIC) located enemy submarines by sending out sound pulses through the water. 
This revolutionary technique was used to locate the Lusitania, which sank off the coast 
of Ireland after a German U-boat attack on May 7, 1915. Echo-sounding evolved by the 
1960s into sonar, which became a standard feature of marine navigation. In addition to 
side-scan sonar,
searchers can now employ sub-bottom profilers to image objects 
buried beneath layers of sediment. Modern satellite global positioning systems (GPS) 
can accurately determine the location of a lost ship in an area as small as 500 square 
miles. 
5
Once a ship has been located, divers are sent to access the wreck, but their 
safety and success depend on suitable equipment. Pioneer divers had to wear heavy 
canvas suits, a copper helmet, lead boots weighing 40 pounds each, and lead weights of 
16 pounds to counteract buoyancy. They could safely reach a maximum depth of only 
200 feet. The time they could spend under water and the speed at which they could 
surface without suffering from the “bends” were severely limited. In the 1940s, 
renowned French oceanographer Jacques Cousteau and associate Émile Gagnan 
developed the Aqua-Lung, or oxygen tank. This improvement in diver safety and 
mobility made diving more popular and treasure hunting more feasible. 
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Cousteau also contributed to the development of saturation diving, which 
allowed divers to live and work from a protected sea habitat. Using a small manned 
submarine called a submersible, divers are able to withstand external pressure at 
depths up to 20,000 feet and to work under water for up to three days. Originally 
developed for scientific and military purposes, submersibles are equipped with robotic 

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