JP 3-50 National Search and Rescue Manual Vol I - US Navy

520 SEARCH AREA
Figure 5-8. Minimax Plotting
A. The search area is the geographic area determined by the SMC as
most likely to contain the search object. The amount of error inherent
in the drift calculations and the navigational capabilities of the
distressed craft and SRU are used to calculate a search radius (R),
centered about datum, for the search area. The radius is normally
limited by the maximum distance the search object could travel after the
incident.
B. For areas such as large lakes, rivers, sounds, bays, or other
coastal areas, the search area may depend on physical restrictions and
time required to respond.
1. When response times are short, the SMC may use a standard
radius, adjusted for physical surroundings. In areas where a
search can begin in less than 6 hours, a radius of 6 nautical
miles is usually large enough to include most targets.
2. Expanding the area based on drift calculations may place a
large part of the area ashore or move datum into the ocean.
If the SMC determines the target probably has moved into open
ocean, and the standard radius may not apply, additional
planning may be needed.
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