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Miscellaneous Notices to Mariners

4.3 Submarine Cables, Overhead Cables and Submarine Pipelines

Both submarine and overhead cables can carry very high voltages, and mariners should be careful when navigating near them. They should also be aware that submarine and overhead cables may not be displayed in the charts. The vertical clearance may also vary due to extreme weather conditions.

Damage to Submarine Cables

Mariners should avoid anchoring and fishing in areas where a submarine cable is displayed on the chart. Anchors and fishing gear can cause severe damage, and disrupt telecommunications or the power supply.

Damage to Submarine Pipelines

Gas from a damaged oil or gas pipeline could cause an explosion, loss of a vessel's buoyancy, serious pollution or other hazards.

Pipelines on the seafloor are not always buried and their presence may effectively reduce the charted depth by as much as 2 meters. They may also span seabed undulations and cause snagging, putting a vessel in severe danger.

Trawling across pipelines at angles of 45° or more is recommended.

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