262 SUBMAKINE CABLE LAYING AND REPAIRING. 



Removal of Fault. — Before the fault comes inboard we may 

 as well look at what Is going on in the testing-room. Ever 

 since the ship began to pick up cable in the direction of the 

 fault, incessant work has been going on in this part of the ship, 

 involving great skill and judgment, and not unfrequently some 

 amount of anxiety. The nature of the work depends upon the 

 kind of fault to be removed, and whether communication can 

 be kept up with the shore during picking up. If the fault is 

 one of high resistance, as is most often the case in these days, 

 communication can be kept up with the shore, and from time 

 to time, as picking up goes on, the superintendent of the station 

 on shore may be requested to test the line while the ship frees 

 or earths the end on board. The results so obtained are com- 

 municated to the ship, and, when taken together with those 

 obtained on board, form a valuable means of arriving at the 

 true position of the fault. An Anderson and Kennelly earth 

 overlap would be tried at intervals, and probably a Mance from 

 both ends. Eingsford's modification of the Blavier would also 

 be tried, and the rate of polarisation carefully watched. If, 

 on the other hand, it were not possible to communicate with the 

 shore, as in a case of low-resistance fault or total break, the 

 ship would rely chiefly on the Schaefer and Eennelly tests with 

 various strengths of current. The subject of testing for the 

 localisation of faults is dealt with fully in Chapter Y. 



The question is often asked, " How near can you ascertain the 

 position of a fault in a cable?" Well, sometimes as near as within 

 50 yards and at other times not within one or two miles. In diffi- 

 cult cases where more than one fault exists it may not be posssble 

 to be certain of the position to five miles or so. The easiest fault to 

 localise is a fracture in which the broken end is insulated, 

 caused by the percha or rubber stretching and closing over it. 

 A total break with a good earth connection probably comes 

 next. Then there are faults of varied sizes, making partial 

 earth ; those which are smallest, and therefore of highest resist- 

 ance, being the most difficult to localise. The greater part of 

 a cable-ship's work on repairs now a days is in removing the 

 latter class of faults of high resistance ; for while the number of 

 cables has gone on increasing by the laying of duplicate and 

 triplicate lines, their manufacture has been so far improved, 

 and the protection against the teredo made so effective by the 



