ROUTE SELECTION AND CABLE LAYING 297 



nautical miles would have resulted in a reduction in the number of voice 

 channels which could be derived from the facility. 



On Fig. 2 are shown a number of the routes to which consideration 

 was given in the early planning stages. The distances shown are actual 

 cable lengths and include an allowance for the slack necessary to assure 

 conformance of the cable to the profile of the ocean bottom. 



Route 1, from Eire to Newfoundland, at 1,770 miles, is the shortest 

 route and in point of fact was provisionally suggested in 1930 for a new 

 cable. But the difficulty of onward transmission of traffic to London 

 made this route unattractive. 



Route 2, from Newfoundland to Scotland, compared favorably in 

 length with Route 1, but its adoption was dependent upon location of 

 a suitable landing site in Scotland. 



Route 3, from Newfoundland to Cornwall, England, approximated 

 2,000 miles laid length and would have been very attractive had not so 

 many existing cables terminated in southern Ireland or the southwest 

 corner of Cornwall, which would lead to a great amount of congestion 

 and consequent hazards to the telephone cables. 



Route 4, from New York to Cornwall, was too long to be considered 

 as its length amounted to some 3,200 miles. 



Routes 5, 6, 7 and 8 were indirect via the Azores. They were attractive, 

 as only relatively short lengths were involved and suitable sites for 

 intermediate cable stations could have been found on one of the several 

 islands in the Azores. But difficulties attendant upon landing rights, 

 and staffing problems in foreign territory could be foreseen. 



Clearance for Repairs 



Repair of a faulty cable or repeater necessitates grappling, and in 

 deep water this is likely to be a difficult operation. To avoid imperiling 

 other cables while grappling for the telephone cables and, con^'ersely, 

 to provide assurance against accidental damage to the telephone cables 

 from the grappling operations of others, it was considered essential 

 that the route selected provide adequate clearance from existing cables. 

 Suitable clearance is considered to be 15 to 20 miles in the ocean, with 

 less permissible in the shallower waters of the continental shelves. 



Trawler and Anchor Damage Possibilities 



It is probable that fishing trawlers cause more interruption of sub- 

 marine cables than any other outside agency. Cables laid across good 

 fishing grounds are always liable to damage from fouling by the otter 



