11.7 Creeping Line Search Pattern
Purpose
To outline the use of creeping line search patterns during search and rescue (SAR) operations involving SLS personnel, services, and assets.
Overview
A creeping line search pattern is a structured search method used where there is a stronger probability that the person, vessel, craft, or object in distress is located closer to one end of the search area.
The search begins at or near the last known position and progressively works away from that point along search lines.
Creeping line search patterns may be useful where the likely direction of movement is influenced by current, wind, drift, river outflow, creek outflow, rip current, or other known environmental factors.
There are two common creeping line search applications:
- Rip to Open Ocean, and
- Open Ocean.
A creeping line search pattern may be conducted by one or more Search Teams, including IRB, RWC, JRB, other approved powercraft, in-water personnel, aircraft, vehicles, or land-based personnel where appropriate.
In South Australia, South Australia Police (SAPOL) is the control agency for all search and rescue activities. SLS personnel may conduct or support creeping line search activity where tasked, authorised, trained, equipped, and operating within approved capability.
SAR activity should be undertaken in accordance with the National Search and Rescue Manual, Control Agency direction, and SLSSA Standard Operating Procedures.
Diagram
Definitions
Creeping line search pattern means a search pattern that begins near the last known position or high-probability end of the search area and progressively works away from that point along search lines.
Rip to Open Ocean creeping line search means a creeping line search used where the last known position is in a rip current, river mouth, creek mouth, bar, or similar outflow environment and the current direction is known or reasonably assessed.
Open Ocean creeping line search means a creeping line search used in open ocean or flat water conditions where the direction of current, wind, or drift is known or reasonably assessed.
Search Team means a person, team, vessel, aircraft, vehicle, or other resource tasked to undertake SAR activity.
Search area means the defined area assigned for search activity.
Search line means one section of the search pattern followed by a Search Team.
Line spacing means the distance between adjacent search lines.
Last Known Position (LKP) means the last confirmed location where the person, vessel, craft, object, or search target was seen or known to be.
Search object means the person, vessel, craft, object, or item being searched for.
Procedure
When to Use
A creeping line search pattern may be used where:
- There is a stronger probability that the search object is closer to one end of the search area,
- The last known position is known or reasonably assessed,
- The likely direction of movement is known or reasonably assessed,
- Current, wind, drift, river outflow, creek outflow, or rip current is likely to influence movement,
- Search lines can be safely and consistently maintained,
- Line spacing can be maintained,
- Communications can be maintained,
- The search area and pattern have been assigned by the Control Agency or approved SLS command role, and
- SLS resources are capable of safely conducting the task.
A creeping line search should not be used where the likely search area, environmental movement, or search direction is not sufficiently understood.
Search Planning
Where SAPOL or another authorised Control Agency has assumed control, search planning remains the responsibility of the Control Agency.
SLSSA may support search planning by providing:
- Last known position information,
- Witness information,
- Local beach and coastal knowledge,
- Rip current observations,
- River mouth, creek mouth, or bar observations,
- Surf, wind, tide, current, and drift observations,
- Search object information,
- SLS resource availability,
- Asset capability and limitation information,
- Communications information, and
- Risk or safety considerations.
SLS personnel must not independently develop or implement a complex SAR search plan where the Control Agency has assumed control, unless directed or authorised to do so.
Pattern Description
The creeping line search pattern begins at or near the last known position or high-probability end of the search area.
Search Teams then work progressively away from that point along search lines.
Search lines should be close enough to provide continuous overlap of vision throughout the search.
The search pattern should be adjusted where current, wind, drift, surf conditions, visibility, or other environmental factors change.
Rip to Open Ocean Method
A rip to open ocean creeping line search may be used in inshore conditions where:
- The last known position was in or near a rip current,
- The current direction is known or reasonably assessed,
- The search object may have been carried from the rip into deeper or more open water,
- The search involves a river mouth, creek mouth, bar, or similar outflow environment, or
- The search area is influenced by a defined outflow or current.
When undertaking a rip to open ocean creeping line search, Search Teams should:
- Confirm the last known position.
- Confirm the search object.
- Confirm the known or assessed current direction.
- Confirm the assigned search area.
- Confirm communications arrangements.
- Confirm SITREP requirements.
- Begin the search at or near the last known position.
- Use a visual reference, marker, buoy, GPS point, landmark, or other approved reference where safe and appropriate.
- Follow the direction of current, outflow, or likely drift.
- Maintain search lines close enough to provide continuous overlap of vision.
- Work progressively from the last known position down-current.
- Observe and report changes from rip current to ocean current where relevant.
- Adjust heading and search lines where the current, drift, or environmental conditions change.
- Record areas searched and any sightings, clues, hazards, or limitations.
- Provide SITREPs to the State Operations Centre (SOC) as required.
Open Ocean Method
An open ocean creeping line search may be used in open ocean or flat water conditions where:
- The last known position is known or reasonably assessed,
- The direction of current, wind, or drift is known or reasonably assessed,
- The search object is likely to have moved along a predictable direction,
- The search should begin at one end of the search area, and
- The Search Team can safely work along equally spaced search lines.
When undertaking an open ocean creeping line search, Search Teams should:
- Confirm the last known position.
- Confirm the search object.
- Confirm the known or assessed current, wind, or drift direction.
- Confirm the assigned search area.
- Confirm line spacing.
- Confirm search speed.
- Confirm communications arrangements.
- Confirm SITREP requirements.
- Begin the search at or near the last known position.
- Use a visual reference, marker, buoy, GPS point, landmark, or other approved reference where safe and appropriate.
- Begin the pattern by following the direction of current, wind, or drift.
- Maintain search lines close enough to provide continuous overlap of vision.
- Work progressively from the last known position along equally spaced search lines.
- Record areas searched and any sightings, clues, hazards, or limitations.
- Provide SITREPs to the SOC as required.
IRB, RWC, JRB or Other Powercraft Method
Where a creeping line search is conducted by IRB, RWC, JRB, or other approved powercraft, the Search Team should:
- Confirm the search area before entering the pattern,
- Maintain the assigned search direction and line spacing,
- Maintain safe search speed,
- Maintain effective lookout at all times,
- Avoid excessive speed or manoeuvring that reduces detection,
- Maintain awareness of other Search Teams,
- Maintain safe separation from swimmers, in-water personnel, other vessels, and the public,
- Consider wind, tide, current, swell, and drift,
- Consider fuel range and endurance,
- Report any area that cannot be searched safely, and
- Provide SITREPs as required.
Where powercraft and in-water personnel are operating in or near the same search area, specific separation, communication, and safety arrangements must be confirmed before commencing the search.
In-Water Search Team Method
Where a creeping line search is conducted by in-water personnel, the Search Team should:
- Confirm the search area and boundaries,
- Confirm the search direction,
- Confirm spacing between searchers,
- Maintain line formation where required,
- Maintain visual or verbal contact where practicable,
- Maintain agreed search speed,
- Maintain awareness of fatigue and exposure,
- Maintain awareness of current, wind, wave action, and drift,
- Avoid entering areas beyond capability,
- Report hazards or limitations,
- Report any areas not searched, and
- Provide SITREPs as required.
In-water creeping line searches should only be undertaken where conditions, supervision, support, communications, and risk controls are suitable.
Multiple Search Teams
Creeping line searches may be conducted by multiple Search Teams where appropriate.
When multiple Search Teams are involved:
- Each Search Team should be assigned a defined search area or search line,
- Line spacing must be clearly understood,
- Starting points should be separated to avoid overlap or collision risk,
- Communications must be maintained,
- Search Teams must remain aware of each other’s location,
- Overlap should be planned where required,
- Search areas completed by each Search Team must be recorded, and
- The SOC or coordinating role must be updated as search areas are completed.
Where Search Teams include a mix of powercraft and in-water personnel, separation arrangements and powercraft safety controls must be clearly briefed.
Line Spacing
Line spacing should be determined by the Control Agency or search planning role where the SAR operation is under agency control.
Line spacing should consider:
- Search object size,
- Visibility,
- Water clarity,
- Sea state,
- Surf conditions,
- Wind,
- Glare,
- Observer height,
- Search speed,
- Available Search Teams,
- Search area size,
- Fatigue,
- Probability of detection,
- Available daylight, and
- Operational risk.
If visibility or detection conditions deteriorate, line spacing may need to be reduced or the task may need to be modified.
SLS personnel should report any concern that the assigned line spacing is unsuitable or unsafe.
Visual References and Markers
Search Teams may use visual references, GPS points, mapping tools, buoys, landmarks, dye markers, or other approved methods to support accurate navigation and coverage.
Where safe and appropriate, a buoy or surface marker may be used to identify the last known position or another reference point.
Markers must not create additional hazards or interfere with other vessels, aircraft, swimmers, or emergency service operations.
Communications and SITREPs
Before commencing the search, the Search Team should confirm:
- Search area,
- Last known position,
- Search direction,
- Current, wind, or drift direction,
- Line spacing,
- Search speed,
- Radio channel,
- Call signs,
- SITREP frequency,
- Emergency process,
- What to do if the search object is located, and
- What to do if the task cannot be completed.
SITREPs should include:
- Current location,
- Search progress,
- Search lines completed,
- Areas covered,
- Conditions,
- Current, wind, or drift changes,
- Sightings or clues,
- Hazards,
- Resource status,
- Personnel fatigue or welfare concerns,
- Any change in capability, and
- Task completion.
Working with Powercraft
Where in-water personnel are operating with or near IRB, RWC, JRB, or other approved powercraft:
- A clear powercraft exclusion or operating area must be established where required,
- The powercraft operator must know where in-water personnel are located,
- In-water personnel must know the powercraft operating path,
- Communications or hand signals must be confirmed,
- Powercraft must maintain safe speed and separation,
- Powercraft must avoid crossing through in-water Search Teams unless specifically required and safe,
- The engine must be managed safely when close to in-water personnel,
- A lookout must be maintained,
- Emergency stop or withdrawal signals must be briefed, and
- The arrangement must be modified or stopped if safety cannot be maintained.
Safety Considerations
Personnel conducting a creeping line search must maintain awareness of:
- Surf, swell, wind, tide, current, and drift,
- Rip currents,
- River or creek outflow,
- Sandbanks, bars, rocks, reefs, jetties, or structures,
- Other vessels or water users,
- Aircraft or RPAS activity,
- Reduced visibility,
- Sun glare,
- Fatigue,
- Communications limitations,
- Navigation errors,
- Collision risk,
- Search Team separation,
- Crew position and lookout effectiveness,
- Fuel or battery limitations,
- Access and egress, and
- Changes in environmental conditions.
Search activity must be managed using a risk versus gain approach.
SLS personnel must not continue a search task where conditions become unsafe or the task exceeds approved capability.
Locating the Search Object
If the person, vessel, craft, object, or clue is located, personnel should:
- Mark or record the location,
- Notify the SOC immediately,
- Provide a SITREP,
- Commence rescue or emergency care where safe and appropriate,
- Maintain observation if immediate rescue is not possible,
- Preserve potential evidence where required,
- Avoid disturbing the scene unless required to save life or prevent further harm, and
- Follow Control Agency or SLS command direction.
Completion of Search Area
When the assigned search area is complete, the Search Team should notify the SOC or coordinating role.
The update should include:
- Search area completed,
- Time commenced and completed,
- Search pattern used,
- Search lines completed,
- Search tracks or route,
- Conditions during the search,
- Current, wind, or drift observations,
- Any areas not searched,
- Any sightings or clues,
- Hazards or limitations,
- Personnel or equipment issues, and
- Whether the Search Team is available for further tasking.
Records
Search activity should be recorded where practicable.
Records may include:
- Assigned search area,
- Last known position,
- Start and finish times,
- Search tracks,
- GPS records,
- Search speed,
- Line spacing,
- Search Teams involved,
- Sightings or clues,
- Areas unable to be searched,
- SITREPs,
- Safety concerns,
- Task modifications, and
- Stand down instructions.
Records should be provided to the SOC for inclusion in the incident log.
References