7/21/2023 0 Comments Covered by water drift![]() This combination is loosely termed the drift of the floating object. Leeway is the downwind component of motion of a floating object due to wind forces, while current will add a component in the direction (set) of the current flow at the speed (drift) of the current at that point. A datum marker buoy should be chosen to drift at the same speed as the target to the extent reasonably practicable, and to remain visible and identifiable during the search. A datum marker buoy is a tool used to mark the movement of the datum during the search and to provide updated estimates for drift speed and direction. The search will usually be started at or near datum. Drift estimates are affected by changes in wind and water conditions, driven by the weather, and may vary with location as the target drifts through more and less sheltered areas. ![]() Search datum is the estimated position of the target at the time the search starts, which is last known position corrected for drift. If the time was recent, the weather and water conditions may not have changed much and drift can be estimated with some confidence. Confidence of last known position and elapsed timeĪ search is greatly facilitated when the last known position of the target is accurately known in time and space.Illumination and atmospheric conditions.Height above the water of the observers.Windage and hydrodynamic drag of the target.Drift speed and direction, which is affected by.įactors influencing choice of search pattern and search asset: ![]() One or more search platforms may be used. ![]() The effectiveness of a search pattern is also influenced by the characteristics of the search platform. Water surface searches are procedures carried out on or over the surface of a body of water with the purpose of finding lost vessels, persons, or floating objects, which may use one or more of a variety of search patterns depending on the target of the search, as the direction and rate of drift vary depending on the characteristics of the target and the water and weather conditions at the time. Procedures to find objects or persons lost at the surface of a body of water ![]()
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