Tuesday, December 28, 2010

12/28 Report - Seal Ring and Griding

Seal Ring Found with Metal Detector.

I'm still hoping someone might have some ideas about the seal.

As I mentioned some time last week, someone asked me what is the proper way to work a beach. There isn't any one right way, but there are a lot of strategies and methods that apply to different situations.

The dry back beach that has not been affected by moving water for a long time is one situation. The low tide zone that is affected daily by moving water is another.

What you are hunting also makes a difference.

So lets look at one fairly specific situation today. I'll start with one of the easiest.

Assume you heard that a valuable ring has been lost near a volleyball court in front of a hotel. In that case the area to be searched is relatively small and well defined. Unless someone already found it, it is probably buried under a inch or two of sand where it was lost.

In that case you simply want to thoroughly cover the defined area. Mark the corners of the defined area and walk in a straight line back and forth until the entire area has been covered. For those of you who don't already know, that is called griding.

You should realize that the natural tendency is to walk too fast. so that your coil on one sweep leaves some area uncovered between sweeps. You need to keep your sweep pattern tight. In fact it is best to overlap successive sweeps. I've had detectors that I would swear detect a larger area than the size of the coil, but generally speaking, the greatest detecting depth is under the center of the coil, and the area under the edges of the coil do not detect as deeply. Therefore, targets under the edge of the coil could easily be missed if buried even a few inches.

Before starting, check the settings on your detector. Generally I would advise against discrimination. A trash item can cause a detector using discrimination to miss a good item that is either under the trash item or very near to the trash item.

There are situations when discrimination can be helpful, but generally speaking I say to use as little as possible.

One good way to check your settings is to use a test target similar to what you are hunting. Put the test target on the ground. For purposes of selecting your settings, you probably won't have to bury the test target.

Adjust your settings until you get the best response from the test target. It won't matter if you cover every inch of sand and put your coil over the target if your discrimination is too high or the other settings on your detector will not detect the target. Make sure you can detect the target before wasting your time.

You might have to adjust your settings very precisely to easily detect small gold chains or other small gold or platinum items.

If you are looking for small pieces of gold, you certainly don't want much discrimination.

I advise practicing at home with various types of targets so you know what your detector will and will not do with the adjustments set to various settings.

Sweep your coil over the test target at different speeds and adjust your sweep speed until you get the best signal from the test target. Practice that sweep speed and use it during your search.

Again, this is one of the simplest scenarios. Griding is a common technique, but it is important to remember to do it well. Don't get sloppy, don't sweep too fast.
Sweep at the best speed and overlap successive sweeps.

Griding can be used for other situations when you want to cover every square inch, but for other types of hunting it would often not be efficient. There is too much sand and too little time to cover every grain.

It is important to learn where to spend your time. To do that you need to learn to read the beach. I'll talk more about that and other strategies and techniques in the near future.

An article in he New York Times suggests that museums should sponsor and conduct digs.

Here is the link.


I wanted to elaborate on one paragraph of this article.

Sadly, when an object is taken from its original site without documentation, context is lost. And in archaeology, context is everything: it tells us an object’s age, its likely place of manufacture and its everyday use. This lack of information makes it harder for collectors to determine if an object is fake, while even authentic works, in the absence of the context of their discovery, become mute witnesses to our irresponsible acquisitiveness.

The situation beach hunters face is that items found on a beach have no context that would tell you much. A beach by it's nature is a very dynamic system. Things do not stay put. They are washed in and out, and separated from their source and other items that they were originally associated with. You are very fortunate when an object is marked in any way that helps you identify the item.

Forecast and Conditions.

Not much has changed recently and it doesn't look like there will be for the next several days. The surf web site is projecting 2.5 foot seas for that long.

Conditions aren't terrible, but for hunting treasure cobs they are poor. The wind is still out of the north/northwest. It is certainly cold.

I think the beaches are still interesting, but not easy.

Happy hunting,