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

C. Overdues can usually be effectively handled by planned buildup
of search effort. By using the repeated expansion concept with a small
coverage factor, a reasonable buildup of search effort can be combined
with an expansion of the search area.
D. If a large-scale search is necessary, it is desirable to
optimize effort subject to the constraints imposed by the planning
variables. The following is a possible method of reconciling the
desired and the attainable:
1. Calculate the optimum rectangular search area (four times the
square of the search radius):
A = 4 x R2
2. For each SRU, calculate available effort as the product of SRU
speed, search endurance, and sweep width:
Z = V x T x W
3. Calculate total available effort, which is the sum of each
SRU's available effort:
Zt = Z1 + Z2 ... + Zn
4. Compare the optimum area to the total available effort to
determine track spacing.
a. If total available effort is greater than the optimum
search area, select a coverage factor for each subarea (C =
1.0 is recommended) and determine the track spacing for each
SRU:
S = W/C
b. If total available effort is less than the optimum
search area, calculate a midpoint compromise search area and
coverage factor, resulting in a compromise track spacing for
each SRU:
Amc = (A + Zt)/2
Cmc = Zt/Amc
Smc = W/Cmc
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