"We expect it will be fishing vessels that damaged the cable but it is very rare that we have two problems at the same time."
And just like that, Shetland goes offline.
Pay attention to subsea cables. Putin does.
bbc.com/news/uk-scotla…
2/ Shetland is connected via SHEFA-2 (SHEtland-FAroes).
If the Mainland-Shetland cable is cut (e.g happened in 2014 near Orkney), backup routing *is* available:
SHEFA-2 to Faroe Islands, then to UK via FARICE-1 backhaul (Faroe & Iceland)
But double breaks = no backup route.
3/ Fishing damage to subsea cables is a big thing.
Bottom trawlers are a common offender.
They can snag surface laid cable segments + gear & make a mess.
They can also muck up marine habitats, as this @MontereyAq video illustrates.
4/ Subsea cables are typically buried.
Sometimes segments wind up exposed for a bit.
Detailed warnings are issued because of the high risk of snagging by trawlers.
E.g. inspection & reburial of a spliced & repaired segment of SHEFA-2 was recently postponed b/c of bad weather.
5/ #Shetland shows: even with redundancy, the right cuts = total outage.
The capability to deliver such a disruptive blow to our information systems is *exactly* why Russia keeps mapping cables & doing exercises.
Story: theguardian.com/uk-news/2022/j…
6/ @mercoglianos just reminded me of some cable cutting history.
Wikipedia has the story of how the 🇬🇧British cut key German telegraph cables at the outset of #WWI.
en.wikipedia.org/wiki/CS_Alert_…
7/ UPDATE: a UK flagged fishing vessel reportedly responsible for #Shetland cable damage.
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