Chart No. 1 · J 9.1
R — Rock, rocky
Seabed
The italic letter R means bare rock — poor, snaggy holding; avoid anchoring if you can.
What it means
An italic 'R' (or 'rky' for rocky) marks a rock seabed: hard bottom with little or no sediment cover.
Why it matters
On rock an anchor either skates or jams — neither is good. If you must anchor, use a trip line so you can pull the anchor out backwards when it snags.