Chart No. 1 · K 14
Sunken rock with known depth
Dangers
A sounding inside a dotted danger circle sits on a rock — that number is the least water over it.
What it means
When a rock's least depth has been measured, the sounding is printed on the rock itself — here 4₆ (4.6 units). A dotted danger circle is added where it endangers surface navigation.
Why it matters
Unlike an ordinary sounding, this depth belongs to a pinnacle — the bottom around it may be far deeper, so it will not show on your depth sounder until you are on top of it.