Chart No. 1 · L 40.1
Submarine pipeline
Areas & limits
A dash–dot magenta line marks an oil, gas, or water pipeline on the seabed — keep anchors away.
What it means
A magenta line of long dashes alternating with dots marks a submarine supply pipeline (oil, gas, chemicals, water). Outfalls and intakes (L 41.1) are charted similarly in black/gray.
Why it matters
Pipelines may stand proud of the bottom, so they can snag gear even in 'deep enough' water. Gas under pressure plus a dragged anchor is a genuinely dangerous combination — give charted pipelines a wide berth when anchoring.