johnny sea ranger
Registered
The usual jackstay pattern is to lay two solid lines parallel on the bottom, then connect them with a third line running perpendicular. Two divers start at opposite ends of the third line, work their way to the other end, then both move the ends of the third line along the other lines, and do it all over again until the 'treasure' is found. The pattern is good for smooth bottom, with or without current, and in poorer visibility.
If the visibility is more than about 3 feet, the standard jackstay pattern wastes time as the two divers are mostly covering the same bit of bottom. They are only arm's length apart. What to do? Here's how to set it up to maximize the ground covered -- so both divers are making their biggest contributions.
Hook a carabiner with some rope on the third line. one carabiner and rope for each diver. The length of these ropes depends on the visibility. Start at opposite ends of the third line, progress til you meet near the middle. then one diver unclips his/her carabiner and re-clips it on the other side of his buddy's. then zoom, away you both go to the end lines. Use floating rope to keep it off the bottom.
I am using this system in flat bottom, no current, visibility 15 feet (and still recognize the lost item), with blinding silt if the bottom is disturbed. The jackstay lines are on stakes, 5 feet above the bottom.
Under the traditional method, each diver is searching 3 ft + 15 ft = 18 feet on each pass. Using the ropes, each diver is searching 15 ft + 15 ft = 30 ft. That's a 30 ft /18 ft = 1.7 factor of increase in ground covered. A 70% saving in air, more or less, which is significant at 80 feet in cold water. In actuality, with the carabiner switching, and more ground to actually look at, and the fact that 15 foot visibility results in about 14 ft search radius if you do the hypotenuse-triangle thing, it's more like 50% more ground covered. Bonus: more ground is covered with, obviously, no increase in surface time between dives.
If the visibility is more than about 3 feet, the standard jackstay pattern wastes time as the two divers are mostly covering the same bit of bottom. They are only arm's length apart. What to do? Here's how to set it up to maximize the ground covered -- so both divers are making their biggest contributions.
Hook a carabiner with some rope on the third line. one carabiner and rope for each diver. The length of these ropes depends on the visibility. Start at opposite ends of the third line, progress til you meet near the middle. then one diver unclips his/her carabiner and re-clips it on the other side of his buddy's. then zoom, away you both go to the end lines. Use floating rope to keep it off the bottom.
I am using this system in flat bottom, no current, visibility 15 feet (and still recognize the lost item), with blinding silt if the bottom is disturbed. The jackstay lines are on stakes, 5 feet above the bottom.
Under the traditional method, each diver is searching 3 ft + 15 ft = 18 feet on each pass. Using the ropes, each diver is searching 15 ft + 15 ft = 30 ft. That's a 30 ft /18 ft = 1.7 factor of increase in ground covered. A 70% saving in air, more or less, which is significant at 80 feet in cold water. In actuality, with the carabiner switching, and more ground to actually look at, and the fact that 15 foot visibility results in about 14 ft search radius if you do the hypotenuse-triangle thing, it's more like 50% more ground covered. Bonus: more ground is covered with, obviously, no increase in surface time between dives.
