Drifting buoys are usually attached to a drogue or sea-anchor and are easy to deploy, operate and measure atmospheric and ocean surface conditions for about 18 months. Drifting buoys have been used for a long period of time in oceanography, mainly for studying ocean currents. In the 1970s, drifting buoys started to be used in meteorology, and can now track and record weather patterns and ocean currents.
Moored buoys are anchored at fixed locations and most are able to collect observations from many different atmospheric and oceanographic sensors. Moored buoys usually work with national forecasting and maritime safety. Moored buoys are usually relatively large and expensive platforms, and can vary from a few meters in height to over 12 meters. Some moored buoys can also be used to anchor ships.
Can buoys, daymarkers and lighted buoys are all marked green. The can buoy marks the right side of a channel leaving a harbor, and will have odd numbers on it. Green daymarkers are used in shallow areas for the same purpose. Green-lighted buoys are found with lights and are found in locations with deep water. They may also have bells or other sound producing devices.
Nun buoys mark the left side of a channel leaving a harbor, and will be red with even numbers on it. Red daymarkers are used in shallow areas for the same purpose. Red lighted buoys will usually have lights and are found in areas with deep water and may have noise producing devices on them.
Fishing buoys are commonly seen in coastal towns and cities, and serve many purposes. Fishing buoys can mark the site of a fisherman's crab or lobster pot, or can mark prime fishing ground. However, the use of a fishing buoy to mark fishing ground has its downside, as it attracts other fishermen and the sight of the buoy may spook the fish. Nevertheless in secluded areas, fishing buoys are beneficial in re-locating prime fishing grounds.
