Question 1

On the chart: “Wk” inside a small dotted circle. That is…

Accepted Answer

A submerged wreck, dangerous to surface craft — Wk in a dotted dangerline marks a dangerous submerged wreck; a sounding beside it would be the least depth over it.

Question 2

“PA” after a charted feature stands for…

Accepted Answer

Position approximate — Position Approximate — the feature exists but its charted position is not accurately determined. PD = position doubtful.

Question 3

A plain cross (+) standing alone in the water is…

Accepted Answer

An underwater rock, depth unknown, dangerous — The bare cross is an underwater rock dangerous to surface navigation; with dots in the angles it is awash at chart datum.

Question 4

An asterisk-like rock symbol (✱) means the rock…

Accepted Answer

Covers and uncovers with the tide — It covers and uncovers; a figure beside it is its drying height above chart datum.

Question 5

“Obstn” on the chart tells you…

Accepted Answer

A danger whose exact nature is unknown or unspecified — Obstruction — something dangerous down there, nature unspecified. Give it the same respect as a rock.

Question 6

An area marked “Foul” is…

Accepted Answer

Safe to cross but never anchor or trawl in — Foul ground: debris or old wreckage on the bottom — no danger on passage, ruinous to anchors and gear.

Question 7

An anchor symbol struck through by a line means…

Accepted Answer

Anchoring prohibited — Anchoring prohibited — almost always cables or pipelines beneath. The plain anchor is the designated anchorage.

Where the chart says “don’t”

This lesson is part of a paid course