Question 1

A wreck symbol on a chart shows a depth of 4m below it and is circled with a dotted line. What does this mean?

Accepted Answer

The wreck is a danger to navigation, with a least depth of 4m at chart datum; the dotted outline is a danger line.. The depth figure gives the least depth over the wreck, referred to chart datum. The dotted outline is a danger line, not evidence that the depth has been established by sweeping. A swept depth is indicated by a distinct swept-depth symbol. Whether passage is safe depends on the vessel's draught, the height of tide and the required under-keel clearance.

Question 2

A sounding of (4) in brackets on a chart indicates:

Accepted Answer

The depth is uncertain, approximate. Chart notation: a sounding in BRACKETS e.g. (4) indicates the depth is uncertain, the figure is an approximation. Figures underlined indicate drying heights (above chart datum). Regular soundings (no brackets, no underline) are depths below chart datum. Admiralty charts now use metres and decimetres, e.g. 4₃ means 4.3m depth.

Question 3

An anchor symbol on a chart indicates:

Accepted Answer

A recommended anchorage or position where anchoring is permitted and conditions are generally suitable for anchoring.. An anchor symbol indicates an anchorage, such as a recommended anchorage position or a designated anchorage area. It need not be enclosed in a circle. It does not guarantee good holding ground or shelter. Consult chart notes, local regulations and sailing directions for restrictions and suitability. Depth contours indicate depth and seabed slope; charted seabed descriptions help assess holding ground. Before anchoring, assess the least expected depth during your stay, under-keel clearance, holding ground, swinging room and shelter from forecast winds. An anchoring prohibition is indicated by the relevant prohibition symbol or area marking, interpreted using the chart legend or Chart 5011.

Chart Symbols, questions and explanations

A wreck symbol on a chart shows a depth of 4m below it and is circled with a dotted line. What does this mean?

A sounding of (4) in brackets on a chart indicates:

An anchor symbol on a chart indicates:

Practise this properly

Chart Symbols, questions and explanations

Questions

A wreck symbol on a chart shows a depth of 4m below it and is circled with a dotted line. What does this mean?

A sounding of (4) in brackets on a chart indicates:

An anchor symbol on a chart indicates:

Practise this properly