PACIFIC CABLE.

Auckland Star, Volume LIV, Issue 90, 16 April 1923, Page 7

PACIFIC CABLE.

THE DUPLICATION PLANS

ROUTE SURVEYED BY i RIS

ACCKLAXD TO FIJT.

,-, ' % "if « ,ddl e °f next August Hie 1 unite Cable will be duplicated between -Auckland and Suva and between Sydney anrl Southport (Brisbane), and 'users will know tliat in the event of a break ..ii the southern triangle formed by Sydney. Suva ami Auckland, there are now ample alternative routes to make it practically certain that total interruption in the triangle will be impossible. From Auckland, for instance we can get through, to Sydney direct, via Sol-folk Island and (when the new line is laid! through Fiji, cutting out Norfolk. lI.M. cable ship Iris returned to her moorings oil' Devonport this morning after four weeks' simoylng, etc.. m connection with the new cable, and as usual Captain W. R. Holmes brings in the ship in spic and span order. Leaving Auckland on the -20th of last month, the Tris carried out the important work of locating the route over which the duplication will be laid.

As everyone with any knowledge of submarine cables knows'the cable is not simply paid out over the stern and left to its own sweet devices in flic matter of finding a lodgment on the bottom of the sea. The route has to he known to a nicety. For instance, there may be a ''deep" between two comparatively close ridges, and it" due allowance were not made for the hollow the cable would be swinging free between the two ridges— a fatal condition for a submarine cable. Then, again, on a rocky bottom a cable would soon chafe itself away, so v. suitable "oozy" route must be found. Tt is interest ins: to know that the AucklandSuva duplication will lie in a snug lied of gloliergina ooze, which practiealv nets as a preservative for the cable. DEEP-SEA SOUNDING. Tn order to ascertain not only the depth of the ocean along the route but to find out what sort of a bottom there is. tin ingenious apparatus known a* Lucas' patent is used on such a trip as that of the Tris. A heavy weight is attached to piano wire having a breaking strain of 27011). When the bottom is reached the weight is automatically released, and what is' known as the lead "snapper" grabs a little sample of the bottom, which is duly examined and its nature recorded when the wire is ■wound on board again. "For the purpose of ascertaining the .temperature away down at the depth at which the Pacific cable lies, a thermometer is attached to She sounding wire, and people not familiar with oceanography will be surprised that down in the dark and lonely neighbourhood of 2000 fathoms the mercury shows .14 degrees Fahrenheit, only two degrees above- freezing point. OVER TWO MILES DEEP. A depth of 23(50 fathoms —just about two miles and a half —was the deepest spot the Tris found on tlie duplication route. Soundings every twenty-five miles or so were taken on the voyage up, and every time a sounding was taken the ship is stopped, so tlie work takes some considerable time. Tlie Lucas sounding machine is an ingenious piece of mechanism, and the paying out and winding in of the thin piano wire can.he regulated to a nicety. Power is, of course, used, and although it is possible to pay out as much as 100 fathoms p?r minute, the actual time it takes for the weighted wire to reach the bottom in, say, a "deep" where the bottom is well over two miles from the surface of the water is considerable, and the first time you watch the whizzing wire paying out minute after minute you are not surprised, that the ancients believed that there were such things as' bottomless pools and oceans. At Suva the Iris did some surveying work at the eastern entrance through the reef in Laucala Bay, through which it is intended to lay tlie duplication instead of through the usual steam|' entrance to the westward. .

A VERY GOOD ROUTE."

Mr. John Milward, the manager ot the Pacific Cable, came down from Suva in the Iris, and speaking to a "Star" reporter this morning, he said the result of the survey was most satisfactory. The bottom was an excellent one for the cable, and the route would be good in every way. The Stretches that were being duplicated, said Mr. Milward, were from Sydney to Southport (near Brisbane) 500 miles, and from .Suva to Auckland direct, 1200 miles. ~ The cost of the work will be £300.000, and both cables should be laid by August 14 next, possibly earlier. The Telegraph Construction and Maintenance Company, which secured the contract, is a well-known British company, and the cable was manufactured at Greenwich. It is interesting to know that the steamer to be used, the Stephait, a vessel of 403.) tons, was formerly a German cable ship, and was handed over in connection with the reparation settlement. She is much smaller than the big cable ship Colonia. the SOOO-tonnner that was used in laying the main part of the britrinaV cable. The past year was a wonderfully busy one for the* Pacific Cable, and when he was asked if the duplication would increase the capacity. Mr. Milward said it would not for the moment, as the question of the duplication beyond Suva, through Fanning Island to Canada, was in abeyance, but the duplication would ensure an absence from interruption j from Fiji downwards. S EXPERIMENTAL (ABLE. | Explaining why the longer duplicaj lion was in abeyance, Mr. Milward said ' experiments were being carried out with | a new design of submarine cable, technicI ally known us the '•continuous load ■ cable." the practical result of which would be (if successful) that the cable would carry eight times as much work as at present. A length of this cable was being manufactured, and tlie Board hoped that within six months they would be able to speak definitely about the results of the experiment. Referrins to the wireless experiments the Board was reported to be making, Mr. Milward said they had nothing to jdo with the question of duplication. j While the Board was waiting for the i result of the "continuous load cable," it I was using lhe interval.to carry on ex--1 periments in wireless both in Fiji and '.Canada. j Mr. Milward intends" to spend about a week in Auckland attending to Board •business, at the end of which he will return to Sydney.