Search Patterns

1
Search Patterns
Boat Forces Center Coxswain C School
Search Patterns -- Rev Nov 05
2
Objectives

• Given the following instruction state common
  terms used in Search and Rescue
• Given basic navigation tools plot and execute
  both precision and drifting patterns

3
References

• National Search and Rescue Manual Vol I II
  COMDINST M16120.5 series
• U.S. Coast Guard Addendum to the National Search
  and Rescue Supplement COMDINST M16130.2 series
• Boat Crew Seamanship manual COMDINST M16114.5
  series
• CG Boat Operations and Training Manual VOL I II
  COMDINST M 16114.32 series

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Value

• The boat Coxswain must be able to execute the
  search pattern correctly, so that lives and
  property in distress have the best possible
  chance for survival

5
Coxswain Responsibility

• Keep crew alert and attentive
• Execute the search pattern correctly
• SOMEONE'S LIFE MAY DEPEND ON IT

6
Search Planning

• Is necessary when the location of a distress
  object is not known, or time has passed since the
  objects position was last known

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SAR Planning

• Where does SAR planning come from?
• The Coast Guard Addendum to the National Search
  and Rescue Supplement COMDTINST M16130.2(series)

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SAR Addendum

• The primary search planning rescue operations
  guidance and policy manual

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Pattern Nomenclature

• Datum
• The most probable location of a search
• object corrected for movement over time

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Pattern Nomenclature

• Explanation of movement
• To locate datum, Two major forces need to
• be considered
• Total Water Current
• Leeway

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Pattern Nomenclature

• Total water current (TWC)

• The sum of all water currents that might be
  acting upon a search object in any given locality

Sea Current Wind Current Reversing Tidal Current
River Current Lake Current Surf Rip Current
The best information on TWC is obtained from a
Datum Marker Buoy.
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Pattern Nomenclature

• Leeway
• The movement through the water caused by winds
  blowing against the exposed surfaces of the
  search object. The more exposed area the object
  has the greater the wind force on the object

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Pattern Nomenclature

• Search Leg
• The track line of the SRU involved in a search
  pattern, or the long leg along the track of a
  parallel or creeping line search

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Pattern Nomenclature

• Cross Leg
• The connection between search legs of a
  parallel or creeping line search pattern

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Pattern Nomenclature

• Sweep Width
• The corrected distance a SRU should be able to
  visually detect the search object on either side
  of the search leg

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Pattern Nomenclature

• Track Spacing
• The distance between adjacent parallel legs
• With the exception of the Sector search which
  will have a radius

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Pattern Nomenclature

• Major Axis
• A bearing line used for the orientation of a
  rectangular search area from the center

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Pattern Nomenclature

• Minor Axis
• A bearing line perpendicular to the major axis

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Pattern Nomenclature

• Commence Search Point (CSP)
• The location in the search area that the SRU
  starts the search pattern

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Pattern Nomenclature

• Initial Response (PIW)
• When searching for people in the water start a
  Sector Search ASAP
• Speed 6 knots
• Track spacing .1 NM
• 1 minute search legs

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Pattern Nomenclature

• Search Area
• The area most likely to contain the search
  object.
• Start with determining datum
• There are 7 different methods

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Corner Method
37º2026N 076º1357W
Corner Method In this method the latitude and
longitude (or geographic features) of each
corner of the search area are given
37º1900N 076º1500W
37º1936N 076º1205W
37º1817N 076º1319W
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Track line Method
37º2145N 076º1422W
Trackline Method The latitude and longitude of
the departure point, turns and destination are
given with a specific width along the track
37º2044N 076º1206W
37º1835N 076º1215W
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Center Point Circular
Center Point, Circular AreaThe latitude and
longitude of the center point are given with a
radius
37º2100N 076º1338W
0.75 NMradius
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Center Point
37º2100N 076º1338W
Center Point, Rectangular or Square AreaThe
latitude and longitude of the center point are
given with the direction of the major axis and
the length and width of the area
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Range and Bearing
140ºT2 NM
Range and Bearing to Center PointThe center
point may also be designated bya range and
bearing from a geographic landmark
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Landmark Boundary
3 NM
BLDG
Landmark BoundaryTwo or more landmarks are
given asboundaries of the search area along a
shoreline
Point Comfort
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Lat/Long Boundary
37º2100N
076º1430W
076º1130W
Latitude/Longitude BoundaryThe sides of the
search area are oriented North-Southand
East-West and the latitude and longitude of
thesides are given
37º1800N
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Pattern Designations

• First Letter Designates Pattern
• P for Parallel
• C for Creeping Line
• S for Square
• V for Sector
• T for Track line
• B for Barrier

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Pattern Designations

• Second Letter Designates Number of SRUs
• S for Single Search Unit
• M for Multiple Search Units
• Third Letter for Supplementary Information
• R for Radar Coordination or Return
• N for Non-Return to Starting Point

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Labeling Patterns

• Plotted in true
• Courses labeled in true and compass
• Turns labeled with DRs and DR times

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PS Pattern

• Parallel track search, Single unit use
• Large area
• Position of search object approximate
• Uniform coverage desired
• Search leg parallel to major axis

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Plotting a PS

• Determine Search Area

Search Area
N (True)
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Plotting a PS
Search Area
Measure ½ track spacing in from the corners
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Plotting a PS
Connect the marks to make the patterns size
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Plotting a PS
Mark CSP, mark full track spacing and lay out
cross legs
CSP
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Plotting a PS

• Lay out search legs, and erase every other cross
  leg

CSP
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Plotting a PS
Label a minimum of three legs a DR at all turns
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CS Pattern

• CREEPING LINE SEARCH, SINGLE UNIT
• USE
• LARGE AREA
• UNIFORM COVERAGE DESIRED
• POSITION OF SEARCH OBJECT IS BELIEVED TO BE ON
  ONE END OF SEARCH AREA
• SEARCH LEGS PARALLEL TO MINOR AXIS

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Plotting a CS
Search Area
N (True)
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Plotting a CS
Measure ½ track spacing in from the corners
Search Area
N (True)
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Plotting a CS
Connect the marks to make the pattern size
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Plotting a CS
Mark CSP, measure full track spacing and lay out
cross legs
CSP
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Plotting a CS
Lay out search legs and erase every other cross
leg
CSP
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Plotting a CS

• Label a minimum of three legs and a DR at all
  turns

CSP
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VS Pattern

• SECTOR SEARCH, SINGLE UNIT USE
• RELIABLE POSITION OF SEARCH OBJECT
• CONCENTRATED AT DATUM
• DATUM AT CENTER
• STARTS AND ENDS AT DATUM
• ALL TURNS ARE 120º TO THE RIGHT
• 1ST LEG IN DIRECTION OF DRIFT

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Plotting a VS Pattern

• Plot datum and arc a full track spacing around it

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Plotting a VS Pattern

• Lay down first track line, either 000 T or the
  direction of drift originating from datum

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Plotting a VS Pattern

• Mark track spacing on either side of the line top
  and bottom

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Plotting a VS Pattern

• Lay out the remaining track lines by connecting
  the marks

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Plotting a VS Pattern

• Label three legs minimum

C- ºT/ ºC D- NM
C- ºT/ ºC D- NM S- KN
C- ºT/ ºC D- NM
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SS Pattern

• EXPANDING SQUARE SEARCH, SINGLE
• UNIT USE
• SMALL AREA
• FIRST SEARCH LEG IS EITHER DIRECTION OF DRIFT OR
  TRUE NORTH
• ALL TURNS ARE 90º TO THE RIGHT
• TRACK SPACING DETERMINES 1ST AND 2ND LEG THEN ADD
  ONE TRACK SPACING EVERY OTHER LEG

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Plotting a SS Pattern

• Plot datum and mark a full track spacing around it

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Plotting a SS Pattern

• Lay down first search leg, either 000ºT or
  direction of drift, originating from datum

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Plotting a SS Pattern

• Lay down search leg 2, 90º to the right of 1
  for the distance of 1 track spacing

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Plotting a SS Pattern

• Add one track spacing to determine length of
  search leg for search legs 3 and 4, plot 3 and
  4

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Plotting a SS Pattern

• Repeat for number of legs required

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Plotting a SS Pattern

• Label all legs

C- ºT/ ºC D- NM
C- ºT/ ºC D- NM
C- ºT/ ºC D- NM
C- ºT/ ºC D- NM
C- ºT/ ºC D- NM
C- ºT/ ºC D- NM
C- ºT/ ºC D- NM
C- ºT/ ºC D- NM
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TSN Pattern

• TRACKLINE SEARCH, SINGLE UNIT,NON-
• RETURN USE
• ONLY INFORMATION AVAILABLE IS THE INTENDED TRACK
  OF TARGET
• START SEARCH AT CSP AND SEARCH THE INTENDED
  TRACKLINE OF THE SEARCH OBJECT

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TSR Pattern

• TRACKLINE SEARCH, SINGLE UNIT,
• RETURN USE
• ONLY INFORMATION AVAILABLE IS THE INTENDED TRACK
  OF TARGET
• CSP IS OFFSET 1/2 TRACK SPACING FROM SEARCH
  OBJECTS INTENDED TRACKLINE
• SRU SEARCHES ONE SIDE THEN THE OTHER OF THE
  SEARCH OBJECTS INTENDED TRACK

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Plotting a TSR Pattern

• Using the target's intended track line, plot
  positions along the track at the origin of your
  search and any turns

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Plotting a TSR Pattern

• Using 1/2 track spacing, arc a circle around
  each plotted position and at the first position,
  plot a line perpendicular to the intended track
  line

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Plotting a TSR Pattern

• CSP will be located at one end of the
  perpendicular line, the finish is the other.
  From CSP lay down the search legs (note the turn)

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Plotting a TSR Pattern

• Label all legs

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Review

• What manual is the primary manual used for
• search planning and rescue operations?

• Coast Guard Addendum to the National SAR Manual

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Review

• What is the definition of datum?

• The most probable location of a search object
  corrected for movement over time

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Review

• What is the definition of a search leg?

• The track line of the SRU unit
• OR
• The long leg along the track of a parallel or
  creeping line search

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Review

• What is the definition of sweep width?

• The distance an SRU should be able to detect the
  search object on either side of the leg

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Review

• What is CSP?

• Commence Search Point
• The location at which the SRU starts the search
  pattern

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Review

• What search pattern is a PS?

Parallel Search pattern Single Unit
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Review

• What search pattern is a SS?

Expanding Square Search pattern Single Unit
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Review

• What search pattern is a TSR?

Track Line Search pattern Single Unit Return
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Questions??