With the water hunting season in full swing, a number of visitors have written asking questions about what type of metal detector is best for specific beach or shallow water hunting applications. I felt that it would be beneficial to select one of these and provide an answer everyone can benefit from as there are several lessons one can learn from it.
The question we received was as follows: “Recently my wife and I decided to get into shallow-water hunting and purchased an underwater metal detector from a large mail-order firm. While the model they recommended has been around for a few years and comes from a well-known company, it does not seem to perform properly when we use it at the beach.
The main problem is that it falses and chatters as soon as we approach the wet sand and gets worse as we enter the surf. Is there anything you can recommend that might help us make some decent finds with our detector.”
Based on the details contained in the E-mail message (some of which were deleted for the purpose of not singling out a specific brand), the detector was a good one; however, however, it was not the best for the conditions the couple was planning on searching in. The detector is a VLF-circuit which is ideally suited for fresh-water hunting. The salt-water conditions in the area they were hunting are what caused the erratic operation of the detector.
Most saltwater beaches also contain mineralized black sand to some degree which adversely affects conventional VLF-type detectors. These units have difficulty in ignoring the rapidly changing mineralization as well as providing accurate discrimination needed to reject unwanted targets. While there are ways to use your detector under these conditions (which I will discuss later in this column), a pulse-induction or multi-frequency VLF detector would provide improved target detection depth in your area.
Having talked with literally hundreds of treasure hunters over the years that purchased their detector from a mail order company in order to save a few dollars, many of them experienced some form of disappointment either in terms of not having the best model for their needs recommended to them or the lack of technical support afforded to them after the sale. In this case, the detector that was recommended is a high-quality, dependable unit that I have used myself; however, it is not known as a detector that works well in salt water.
If they had gone to a local dealer or talked with local treasure hunters, they would have had the opportunity to find out what worked well in their area and purchased a unit that probably would have allowed them to find more than they saved by buying from a mail order company a thousand miles away.
With that said, there are a few things that you can do to improve your detector’s performance at the beach. First of all, by reducing the sensitivity level on a VLF-type detector, you are reducing the affect that the salt and black sand has on the detector’s operation. This can be explained by the following analogy. The sensitivity control on your detector can be equated to the high / low beam control for your car’s headlights. On a clear night, your high beams will allow you to see much further than your lot beams would. On the other hand however; on a foggy night, the high beams will reflect back towards the vehicle resulting in almost a total loss of visibility.
The low beams will actually allow you to see much further under these conditions. Similarly, by reducing the sensitivity on your detector, you are minimizing the affect the salt & black sand has on the detector and the signal from your coil will provide you with more USABLE depth which is all that really matters in the field.
Another trick is to hold the coil a few inches above the sand while searching. As with reducing the sensitivity setting, holding the coil off the surface of the beach will reduce the effect mineralization will have on your detectors performance.
My final recommendation was that if they were still not satisfied with their detectors operation, they might want to consider one of the pulse-induction or multi-frequency VLF type detectors currently on the market. Both types will perform considerably better than the model they now have in salt water conditions.