Spar buoy

A spar buoy is a tall, slender, often cylindrical buoy that stands upright in the water. Its design emphasizes vertical stability, making it less susceptible to being capsized by waves and currents compared to other buoy shapes.

Spar buoys are typically used as navigational aids to mark channels, hazards, or special areas in waterways. They are easily visible due to their height and are frequently equipped with lights, reflectors, or radar reflectors to enhance their visibility, especially during nighttime or periods of reduced visibility.

The color and marking patterns on a spar buoy adhere to established maritime buoyage systems, such as the IALA (International Association of Lighthouse Authorities) system, to convey specific information to mariners about the location and nature of the feature being marked. These color and marking schemes vary depending on the region (IALA A or IALA B).

The construction of a spar buoy typically involves a hollow metal or plastic tube that is sealed to prevent water ingress. Ballast is often added to the bottom of the buoy to lower its center of gravity and improve its stability. The top of the buoy may feature a daymark (a distinctive shape and color combination) to further aid in identification.

Spar buoys are commonly used in areas with relatively strong currents and wave action where a more stable platform is needed for reliable navigation marking.