Topmark (2)

urn:mrn:iala:dic:2-6-0255

One or more relatively small objects of characteristic shape or colour (or both), placed on top of a navigation mark (or buoy) to identify it. (Figs. 65 and 66)

Note 1: A topmark may be

• a. Simple
• b. Composite, viz. made up of two or three individual topmarks.

Note 2: The following characteristic apparent shapes of topmarks are internationally recognised for the lateral system of marking (or buoyage):

• Cone
• Can
• Sphere
• Diamond
• St. George's Cross
• "T"
• Broom

A broom topmark has the appearance of a circular broomhead and has two forms "Broom, point upwards" (in German, "mit Besen abwarts") and "Broom, point downwards" (in German, "mit Besen aufwarts").

Note 3: The following characteristic apparent shapes of topmarks are internationally recognised for the cardinal system of marking (or buoyage):

• Two cones, point upwards
• Two cones, point downwards
• Two cones, point to point
• Two cones, base to base

Note 4: Other forms (e.g. St. Andrew's Cross) are used, for example, as landfall marks.

Note 5: In the U.S.A. the word Daymark is often used for a topmark.

Please note that this is the term as it stands in the original IALA Dictionary edition (1970-1989)

English

ampere

second

Time period

roll period

Transmissivity

acceleration due to gravity (m/s2)

South

International Association of Marine Aids to Navigation and Lighthouse Authorities - AISM