Search Patterns
Initial track spacing < 15ft good conditions
0.5 nm
Initial track spacing for PIW
0.1 nm
Initial track spacing 15ft or > good conditions
1 nm
Orientation
Direction of first search leg
Track spacing
Distance between 2 parallel search patterns
Creep
General direction in which an move, same direction as cross legs
Minor axis
Short side of a rectangle
CSP
Location to start the search pattern
Expanding square search
Small area where some doubt exist, uniform coverage, start at datum, first leg usually into wind or current, use when confident the datum is within close limits, turns 90 to the right
Initial track spacing poor conditions
Winds 15 kts or greater Sea 3 ft or greater
Initial track spacing good conditions
Winds < 15 kts Seas < 3ft
Initial track spacing 15ft or greater poor conditions
0.5 nm
Major axis
Long side of a rectangle
When is a track line search used?
Used when the intended route of the search object is known
Initial track spacing < 15ft poor conditions
0.2 nm
Cross legs
Connection between 2 search legs
Search legs
Long leg along the track of any pattern
Datum
Most probable location of the search object corrected by movement over time
Parallel search
Used for large, fairly level area, where equal probability of object in search area, and uniform coverage, search legs along the major axis
Creeping line search
Used to cover one end of an area first, large area, uniform coverage
Barrier search
Search legs perpendicular
Victor sierra multiple units
Second SRU starts 90 to the left of the first leg of first SRU
Victor sierra search
Used when datum is established within close limits, very high coverage is desired, area to be searched is not extensive, first leg is in direction of drift, turn 120 to right, second pattern starts 30 to right of final course