Chart No. 1 · D 26

Overhead cable (with clearance)

Areas & limits

Pylons and a sagging magenta line across water, with the safe vertical clearance printed beside it.

What it means
Pylon symbols joined by a curved magenta line mark an overhead power cable crossing water. The safe vertical clearance (e.g. '22 m') is printed at the crossing, measured above a high-water level.
Why it matters
Compare the clearance with your air draft honestly — and remember high-voltage lines can arc to a mast before contact. Sailboats have been lost to 'plenty of room' guesses; if in doubt, don't pass under.
Open the official NOAA reference