NAUI Master Scuba Diver 224 Search and Light Salvage A very minute search can be conducted. If the bottom is soft and the item being sought is small, sifting the mud or sand square by square may be necessary to recover the object. Jackstay Search The jackstay search is used to cover a relatively larger area on a flat bottom (figure 9-6). A base line is established on one edge of the search area and a movable line is laid perpendicular to the base line (often by compass). There are many variations of the jackstay search pattern. A second line paralleling the baseline is placed at the opposite edge of the search area. Using the movable guide line, divers can systematically search an area (by feel, if necessary). This search is conducted by having two buddy teams swim in opposite directions parallel to a guideline. The inside diver of each team maintains gentle contact with the guideline and the other diver may (in poor visibility) maintain contact with the guide diver by holding on to the diver’s harness or a separate short buddy line. Using their free hands, the divers sweep and feel for the object. When each team reaches the base or edge line, they signal the other team using two distinct line pulls. If the other team has reached the other perimeter (or edge of the search area), they return the two pulls and the line is moved a predetermined distance, depending on the visibility and search precision requirements. Search precision requirements relate to the size and value of object. The guideline would be moved in smaller increments in a search for a diamond ring than in a search for an outboard motor. The teams then swim in the opposite direction. This procedure is repeated until the search area has been covered. Some recommend that this search be conducted by two individual divers (instead of two pairs of divers) moving along the line in opposite directions. Although it is slightly easier for the divers to coordinate using only two divers and the procedure requires less personnel, it does separate the dive buddies. This violates the buddy diving protocol of recreational divers. A running jackstay search pattern is useful for searching small elongated ponds. This technique requires the placement of a line tender on opposite shores. A line is stretched between the tenders and allowed to sink to the bottom. The search divers (a buddy team) swim along the line feeling the bottom. One diver may be positioned on each side of the line. When the divers reach the opposite shore, the line is moved a predetermined distance by the tenders and the search is continued in the opposite direction. The procedure is repeated until the designated area has been covered. LIGHT SALVAGE PROCEDURES When the object of your search has been located, the next step is to recover it. That can be as simple as picking it up or as complex as rigging a hoist or lift bag and raising the object. In addition to the previously listed gear needed for salvage work, you must also be equipped with specific knowledge and skills for the recovery task. Physics calculations are often required to lift an object from the bottom (see examples in “Diving Physics” chapter). The following principles and procedures are important and should be studied carefully. FIGURE 9-6. JACKSTAY SEARCH PATTERN.
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