3.3.CORE SKILL 2 – VISUAL SEARCH USING AN AID
3.3.1. TRIPWIRE ‘FEELER’ The most common aid to visual search is a tripwire ‘feeler’. This tool is used in a systematic manner to focus the eye of a searcher on a precise point and can be used from ground level to above head height. The feeler is normally a length of moderately stiff wire that may be painted to enhance its effectiveness as an identification tool. It works by focusing the eyesight of the searcher, and the movement that is used should be slow and cautious, enough that the risk of the feeler inadvertently touching a tripwire is minimised.
ׁ HINT. The tripwire ‘feeling’ procedure takes time and should only be conducted when tripwires or other surface-laid switches, such as crush wires, have been assessed as being present.
3.3.2. FUNDAMENTALS OF USING A TRIPWIRE FEELER
The whole width of the lane to be cleared should be examined for tripwires and other component parts. There are two methods that are commonly used:
The box method. The searcher pushes the tripwire feeler into the lane parallel to its sides on the left, centre and right systematically, before raising it to the desired height whilst visually searching. This method is shown in Image 1.
Search lane progression and boundary markers
Tripwire feeler
Image 1. Box method – tripwire feeling
The crow’s foot method. The searcher pushes the tripwire feeler into the lane on the left, centre and right systematically from the centre of the lane before raising it to the desired height whilst visually searching, as in the image below:
Search core skills and procedures
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