Written by the Treasureguide for the exclusive use of the Treasure Beaches Report.
Treasure hunting obviously involves seeking or searching, but humans are seeking all the time. When you look at the computer or phone display, you are seeking and doing it in a very systematic if not consciously planned way. When you look at a display screen you expect t find things at certain places. You do not first look at the extreme corners of the display screen. You generally look first at the center of the display in a fairly unfocused way. When you read, you track the sentences and words and know where to expect the next one. The point is that you are almost always scanning and seeking - sometimes being led by what you see and sometimes n a more general way.
There is more than one type of seeking involved with treasure hunting. There is the hunting you do in the field, and there is the research process in which you seek information either about a treasure that has yet to be found, or about a find that has not been totally identified.
Much human behavior is seeking behavior in one way or another and at one level or another, but I'm going to focus on search patterns today - and only a small number of those.
Most every detectorist knows something of the grid search pattern that would be used when you want thoroughly cover all of a limited or defined space. When using a magnetometer in the water that might be referred to as mowing the lawn.
There are actually several important details that should be noticed about the way the grid pattern is illustrated above. Unlike how detectorists sometimes do it in the field, the illustration shows a pattern that tracks both horizontally and vertically. I doubt that many detectorists actually work their grid in both directions, although that could definitely be productive for two reasons. If the individual paths are close enough together, it provides double coverage, but not only does it provide coil overlap, the coil is swept in two distinctly different directions. That can be important because, as I've shown in the past, some objects (particularly elongated objects or those that aren't round) will produce a much stronger signal when swept over in one direction and a week or almost non-existent signal when the coil moves in a perpendicular direction.
There is a lot more that could be said about a grid search pattern. Most importantly, if you are right-handed for example, you'll swing your coil more to the right side, which means your paths should NOT be equidistant if you want thorough coverage without overlap.
By the way, the illustration at the top of this post was adopted from a book on crime scene investigations but applies well to other kinds of searches, including metal detecting.
I would seldom start out with a grid pattern unless I had reason to believe it was worth the time. You can't cover an entire beach, so if you grid an area, I should have reason to believe it is worth the time covering the area well rather than searching elsewhere.
Let's skip to the spiral pattern now even though there is a lot more that could be said about a grid pattern. I introduced the spiral pattern many years ago, and then went on to explain the linked spiral pattern.
Below is an illustration of the spiral pattern that also crudely shows the sweeps of the search coil.
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| Spiral Sweep Pattern. |
The illustration shows the detectorist initially going right to left until a good target is encountered and then spiraling out from that target.
We know that targets often cluster. There can be spills and there can be collection points or holes.
I like the spiral pattern for hunting in the water when there is low visibility and rough water. Once you recover a target, you can use the hole to orient yourself. It is impossible to grid in the water when the water is rough, and you can't see the bottom. I would stick my scoop in the hole and circle around. You can keep track of where you are in relation to the hole that way.
When recovering a target in water, especially rough water, it can be difficult to recover the target, which can fall out of the scoop or get washed to the side, so you want to be able cover the hole and area immediately around the hole very well. And it is not uncommon to encounter a cluster of targets.
As you proceed out from the center and hit additional targets, you can start a new spiral. I call that a linked spiral pattern (as shown below). The dots indicated good targets
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| Linked Spiral Pattern for Metal Detecting. |
When you move on from one spiral, and encounter a new good target, you can start a new spiral. You can do that multiple times.
In the water, the clustering of targets, difficulty of staying put in one spot, and difficulty of recovering targets, make the spiral pattern a good choice.
Of course, there are many other search patterns. I'll just get into one more right now. It is a very common pattern that I talked about years ago - the zig-zag pattern.
I was watching one of the popular reality TV treasure shows and the detectorist claimed that a zig-zag pattern was indicated. I disagreed. There was nothing about the situation to recommend a zig-zag pattern. There are other patterns that would have been more appropriate.
I especially like to use a zig zag pattern on the wet sand area between the berm and water. It is good for locating coin lines and coin holes. As always, the tightness of the pattern can be adjusted depending upon various factors.
Just like when watching TV or looking at a display screen, not all areas of a beach will be of equal interest. As information is taken in, you will select or adjust your search pattern.
A zig zag pattern can be used to locate coin lines or holes.in the wet sand. I don't use a tight pattern to locate lines or holes, because if the target density is sufficient, you don't need a tight pattern. You can tighten or change your search pattern after locating a line or hole.
Once you locate a good target or targets, that changes your estimation of the situation, and you can then modify your search pattern. The tightness of your pattern will depend upon the anticipated density of good targets, but also the expected value. If you think there is a good possibility of a high value, you'll probably want to use a tighter search, for example. Both the expected or anticipated quantity and quality of targets will affect your strategy.
There is much more to say about search strategies, but I'll stop there for today.
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| Source; nhc.noaa.gov |