Lessons From the Zeus Cable Build: WWII Bombs & Sand Waves

This article illustrates the challenges in laying fibre optic subsea cables. Zayo found 3 unexploded bombs in British territorial waters and one on the Dutch side during its Zeus cable build across the English Channel. I guess the Netherlands is doing better than Brexit UK because the Dutch navy removed the bomb while Zayo was required to hire private third parties to remove the other 3. 😀 There were also over 350 potential archeological sites that had to be examined prior to the cable run.

Zayo viewed building Zeus as a necessity given the advanced age of the North Circe cable (22 years now) and the fact it was tapped out. This has been my point as well. These English Channel cables are approach life's end either due to optical loss accumulating from many repairs or simple technological obsolescence. However, the article's writer goes a little overboard in claiming that a ship anchor would bounce off Zeus' double armored cable. I am highly confident it would go right through it like a Samurai sword through a chicken roast. 😀 One other interesting point is the sand wave threat to North Sea cables. A sand wave is where a strong current or tide lifts up entire layers of sedimentary muck and leaves a buried cable exposed on the sea floor. Sand waves can easily make two meters of sediment disappear. Zayo buried its cable almost as deep as Scylla and the two cables are strikingly similar in design including ultra-low loss glass and 96 pairs with no optical amplification. 

A new cable like Zeus or its competitor Scylla has probably the same operating cost as a 20 year old cable like Concerto or North Circe. But the new cables have much higher revenue potential due to higher capacity and a greater life expectancy. So I believe that the older cables be shut down in the next give five years with ten years as the max.