Wednesday, September 14, 2016

Mom, Kelp Ate My Cable

Mom, Kelp Ate My Cable!
Al Richardson, VP Technology

Yes, it really did, as strange as it may seem. One could understand underwater Zombies maybe, but Kelp? Who would ever consider Kelp as a threat to a cable.  Let me explain.  The other week during one of R&R’s status meetings we wandered off topic and started discussing the weird and not so weird causes of cable faults. As a company and as individuals our experience in design, fabrication, testing, and installation is hard to beat. Over the years we have seen some pretty “interesting” reasons why cables have faulted.  Everything from Southwestern Jack Rabbits and Dungeness Crabs just to name a couple. One of the more interesting reasons one would not expect is Kelp.

Here is how it happened.  During the field testing of a very small powered optical cable known as the 132 cable (the diameter is 0.132”) a study was performed on how the cable would behave on the sea bottom. I had the assignment to deploy the cable over various bottom conditions and observe the cable status and performance. An area was found where there was sand, mud, rock, gravel, and yes, Kelp on the bottom. After deployment and initial observations by divers, all was well. After a week went bye I set up an inspection schedule and departed for home.  Then two months into the one-year test, I received a call at my office.  I was told ‘the Kelp ate your cable’.  Right, sure it did. It took a bit to convince me. When we did the inspections, analysis the facts did show that Kelp was the main contributing factor to the fault.  As one learned, at the various stages during the life cycle of Kelp, it floats.  If you have a very small cable in a Kelp bed, you run the risk of the Kelp bringing the cable to the surface where the prop of a boat engine, or by some other surface means, the cable can break. And that’s what it did!

Who knew? Now, I do.  Who knew about underwater marching sand dunes? Who knew that a small tsunami could take out a shore landing? Who knew that a skate would unbury a cable to take a bite out of it?  Who knew, well R&R System Solutions does and has had the pleasure (as the Chinese say) of “living in interesting times ” involving undersea cable.

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