Straits of Mackinac
CLIENT EVALUATION REPORT – ENBRIDGE
Subsea pipelines | Straits of Mackinac, Michigan, USA
Enbridge’s Line 5 is a 645-mile, 30-inch-diameter pipeline that travels through Michigan’s Upper and Lower Peninsulas. As it travels under the Straits of Mackinac for a distance of 4.5 miles, Line 5 splits into two 20-inch-diameter, parallel pipelines. Line 5 carries up to 540,000 barrels per day of light crude oil, light synthetic crude oil and natural gas liquids.
Built in 1953, the Line 5 Straits crossing has never experienced a leak in more than 60 years of operation.
However asset owners need to be geared up, as it’s really a question of when an incident will occur. This recently proved true in the Straits of MacKinac, Michigan, when a significant incident took place.
Apr 2018
The Detroit News
“Tug Clyde S. Vanenkevort dropped an anchor that ruptured a pair of power cables and dented Enbridge’s Line 5 oil pipeline under the Straits of Mackinac. The power transmission cables leaked about 600 gallons of dielectric oil.”
This incident led to the commissioning of an important piece of research by Enbridge into mitigating anchor strikes.

Enbridge Line 5, Straits of MacKinac
Salient points of the report
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Guardian Asset Protection Solution will reduce the risk of Anchor Strikes by 88.4%
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Enbridge evaluated two marine AIS technologies and determined that Vesper Marine’s Guardian: protect system potentially provided the most benefit to Enbridge in mitigating anchor strike risk.
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Guardian: protect meets Enbridge’s needs because it provides the ability to send early-warning messages directly to vessels that pose an anchoring risk.

Traffic density map along the Straits shipping channel
Evaluating preventive measures
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Guardian Asset Protection Solution will reduce the risk of Anchor Strikes by 88.4%
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Guardian Asset Protection Solution will reduce the risk of Anchor Strikes by 99.9% when used with a barrier of engineered gravel and rock over the top of the pipeline.

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Comparison of AIS technologies
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Vesper Marine’s Guardian: protect system potentially provides the most benefit to Enbridge in mitigating anchor strike risk.
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Guardian: protect has the ability to send early-warning messages directly to vessels that pose an anchoring risk.

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