Page 22: of Offshore Engineer Magazine (May/Jun 2020)

21 23

FEATURE SUBSEA ASSET PROTECTION

Getting Physical

Tons. Analysis of fshing vessel data found that the world’s

For the frst 150 years, the primary defense against damage by fshing feet doubled in size from 1950 to 2015, reaching 3.7 vessels was through enhanced physical protection. Cables and million vessels.

pipes were buried in high marine traffc areas, particularly where

Surely things are getting better there was a risk of dredging or anchoring. Where possible, phys- ical buoys were deployed. Marine charts were clearly marked More vessels with bigger anchors, heavier dredges, and larg- to show the location and area of some subsea cables and pipes. er nets has resulted in more damage to marine infrastructure

But even burying cables and pipes and marking them on than ever before. A few recent examples… charts wasn’t a guarantee of protection, as New York Power April 2018 was a dark month with three major incidents.

Authority discovered twice within a 10-year period. Despite These included the loss of 5 lives in Indonesia when a vessel its cables across Long Island Sound being buried 10 ft. under dropped anchor in a restricted area and dragged a Pertamina the seabed, anchor strikes ruptured cables resulting in mil- pipeline causing it to burst. In Port O’Connor, Texas, a dredge lions of dollars in repairs each time. caught on fre after hitting a subsea gas pipeline, and in the

Straits of Mackinac, on The Great Lakes, a dragging anchor

The risk to subsea infrastructure grew exponentially dented a major pipeline and damaged electric cables causing

Despite all attempts, two factors resulted in ever-increasing a mineral oil leak.

risk and damage to marine assets. The frst was the incredible On December 23, 2019, Malta lost power for 3 hours after growth in subsea infrastructure. By way of example, subsea a vessel’s anchor cut a power line to the country. The cost of pipelines in the Gulf of Mexico went from zero in 1953 to repair and mitigation is estimated to be over 20 million Euros.

over 28,000 miles today. As recently as January 9,

Secondly, the number and size of vessels dramatically in- 2020, 14 countries in West creased. The OECD reports that from 1900 to 2000, the Africa experienced massive number of maritime shipping vessels grew from under 30,000 telecom disruption when to nearly 90,000 ships. The size of these vessels increased even the FALCON cable was more dramatically, with total Gross Tons increasing more cut in two places by a sus- than 11 times, from less than 50 million to over 550 million pected anchor drag.

Source: Vesper

The Akaroa installation 22 OFFSHORE ENGINEER OEDIGITAL.COM