XV 



World Voyage Begins 



ALTHOUGH not an old ship by many standards, Challenger, 

 by the end of 1949, saw her end in sight. Four new sur- 

 Lveying vessels had been completed since the War and 

 new there was talk of one or even two newer ships being planned 

 for the Surveying Service. Challenger was by far the oldest sur- 

 veying ship and her end could not be far distant. It must have 

 been pleasing for the old ship to realise, on her return from the 

 Persian Gulf in 1949, that she was to be prepared for something 

 unusual. This was to be a world cruise, and how better could she 

 complete her career than following in the track of her famous 

 predecessor? 



It had been planned that Challenger should carry out a two- 

 and-a-half-year sounding cruise, visiting the three main oceans 

 and the Mediterranean. 



The great number of charts maintained by many of the countries 

 of the world are devoted almost entirely to depicting the depths 

 of the inshore waters on the continental shelf, such charts having 

 navigational value. But since the end of World War II interest 

 in the topography of the deep ocean floor has been growing. 



For long such areas had been considered, by those who thought 

 about them at all, as having a flat and featureless sea-bed, carpeted 

 with sediments. But the earlier Challenger's soundings, although 

 she was able to obtain only about 400 of them with her laborious 

 methods of rope and sinker, already showed that there were many 

 features, hills and valleys, on the ocean floor. With the laying of 

 the first trans-ocean cables at the end of the last century there 

 came a steadily increasing knowledge of the features forming the 

 ocean bed, and such knowledge was rapidly augmented by the 

 introduction of echo sounding machines in research and sur- 

 veying vessels in the early 1930s, 



During World War 11 the neutral Swedes had time to think 

 about oceanographic research, but their practical experiments 



i8s 



