Cardinal mark symbol

A buoy with two cone topmarks, saying which side of a danger holds safe water.

Also known as: Two cones buoy, Triangle topmark buoy

Maps & navigationSafety & hazardStandard profile

Meanings

A cardinal mark says which side of it is safe: the two black cones on top point in a pattern that names a compass quadrant. The topmark is the message, and it is the same by day and by night.

Officially standardisedVerified fact
States which side of a hazard has safe water, by the arrangement of two black cone topmarks: both up for north, both down for south, points together for east, bases together for west.
Contexts: Navigation
Officially standardisedVerified fact
Repeats the same information in its black and yellow banding, so the mark can be read at a distance before the topmark resolves.
Contexts: Navigation
Common modern usageVerified fact
Belongs to a buoyage system whose lateral marks — the red and green ones — reverse their meaning between world regions, while cardinal marks do not.
Contexts: Navigation

Visual description

A pillar or spar buoy banded in black and yellow, carrying two solid black cones one above the other at its top, arranged point-up, point-down, points-together or bases-together.

Symmetry: none
Orientation: upright
Colours: black, yellow

Part of the same system as: Lighthouse chart symbol
Aids to navigation defined in one standard.

Confidence

IdentityHigh confidence: High confidence because the identity is defined by a current official standard, but multiple independent sources agree.
Historical originModerate confidence: Moderate confidence because the historical origin is documented in encyclopedic references, but multiple independent sources agree, but early or supporting evidence is limited, but the regional or cultural match to this specific claim is not precise.
Current useHigh confidence: High confidence because the current use is defined by a current official standard, but multiple independent sources agree.
Visual matchHigh confidence: High confidence because the visual match is documented in encyclopedic references, but multiple independent sources agree.

Sources

Nautical chart
Wikipedia · retrieved 2026-08-01
Tertiary reference. Used for what a symbol depicts and which authority publishes it, not for the legend of any particular chart series or the text of any standard.
Sea mark
Wikipedia · retrieved 2026-08-01
Tertiary reference. Used for what a symbol depicts and which authority publishes it, not for the legend of any particular chart series or the text of any standard.
INT 1 — Symbols, Abbreviations and Terms used on Charts
International Hydrographic Organization · retrieved 2026-08-01
The internationally agreed chart symbol set, adopted by member hydrographic offices. Cited for the existence and authority of the standard and for the broad meaning of widely-reproduced symbols; the publication itself was not read, so no record cites it for a specific plate or entry number. See docs/paywalled-standards.md.

Last reviewed 2026-08-01

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Map, chart and weather symbols

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Meanings

A cardinal mark says which side of it is safe: the two black cones on top point in a pattern that names a compass quadrant. The topmark is the message, and it is the same by day and by night.

Officially standardisedVerified fact

States which side of a hazard has safe water, by the arrangement of two black cone topmarks: both up for north, both down for south, points together for east, bases together for west.

Contexts: Navigation

Officially standardisedVerified fact

Repeats the same information in its black and yellow banding, so the mark can be read at a distance before the topmark resolves.

Contexts: Navigation

Common modern usageVerified fact

Belongs to a buoyage system whose lateral marks — the red and green ones — reverse their meaning between world regions, while cardinal marks do not.

Contexts: Navigation

Confidence

IdentityHigh confidence: High confidence because the identity is defined by a current official standard, but multiple independent sources agree.
Historical originModerate confidence: Moderate confidence because the historical origin is documented in encyclopedic references, but multiple independent sources agree, but early or supporting evidence is limited, but the regional or cultural match to this specific claim is not precise.
Current useHigh confidence: High confidence because the current use is defined by a current official standard, but multiple independent sources agree.
Visual matchHigh confidence: High confidence because the visual match is documented in encyclopedic references, but multiple independent sources agree.

Sources

Nautical chart
Wikipedia · retrieved 2026-08-01
Tertiary reference. Used for what a symbol depicts and which authority publishes it, not for the legend of any particular chart series or the text of any standard.
Sea mark
Wikipedia · retrieved 2026-08-01
Tertiary reference. Used for what a symbol depicts and which authority publishes it, not for the legend of any particular chart series or the text of any standard.
INT 1 — Symbols, Abbreviations and Terms used on Charts
International Hydrographic Organization · retrieved 2026-08-01
The internationally agreed chart symbol set, adopted by member hydrographic offices. Cited for the existence and authority of the standard and for the broad meaning of widely-reproduced symbols; the publication itself was not read, so no record cites it for a specific plate or entry number. See docs/paywalled-standards.md.

Last reviewed 2026-08-01

Meanings

Visual description

Related & commonly confused symbols

Meanings

Visual description

Related & commonly confused symbols