Written by the TreasureGuide for the exclusive use of the Treasure Beaches Report.
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| Bronze Nail Found by Michael T. |
I received the following message and find photos from Mike T.
Good morning Mike T here from Stuart! My wife and I got out for some hunting Friday and found a few good spots where sand had been stripped.
Not a lot of targets but a few good ones.
The waves were still very powerful so it was hard to get low on the beaches.
I was really excited to see the bronze square nail come up as I haven’t found one in a long time. It is especially cool due to the shape!
The other item of interest was coin shaped but as you can see from one of the photos it appears to have some rust on it so I was skeptical. I decided to put it in some electrolysis this morning and lo and behold it’s a Mercury dime! This came from the bottom of a big horseshoe cut and was only 1 of 2 targets I dug there.
By the way, I saw that you recently started using a mini lab Manticore. I’ve been using one now for about a year and I love it. It definitely took some getting used to even from my Equinox 900 but what a powerful tool it is!
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| Michael T.'s Finds. |
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Part III. How coins move on a beach.
So far I've talked about sand a lot. On a beach you can't talk about coins moving without talking about how the sand moves. In some cases, such as when water undercuts a dune cliff, it is the movement of sand that causes the movement of the coin, which will slide down the cliff face as the sand is eroded out from below. The same kind of thing happens when a cut is further eroded. I've seen coins slide down the face of a dune, and I've seen coins fall out of an eroding cut.
Furthermore, if coins are covered by sand and protected from the force of water, the coins will tend to remain stationary. In that case, the sand must be moved before the coins will be moved.
It might help to look at a beach as consisting of several zones. Starting at the top, we have the dunes, which on the east coast receive a predominant east wind that, on net, blows the sand up the slope, onto and over the dunes, causing dunes to migrate to the west.
Below the dunes you will often see a flat beach between the slope and the dune face. On other beaches the beach will be narrower, and the slope will end at or close to the dune fact. You'll see those two types of beaches on the Treasure Coast. John Brooks, for example is the second type. There is not s cut dune face there. The beach slope is normally well out in front of the dunes.
Then there is the slope, which can vary in steepness. Higher wave energy beaches are steeper and are composed of larger grains of sand or pebbles than more gently sloping beaches.
Sticking with the beach, the water washes in and then out again. Depending upon the wave period, the returning water will clash with the incoming water from the next wave. When the water is high, the water can bounce off the dune cliff, which makes the water running down the slope much faster, but when that is the case, you also have a lot of incoming water. That is all simple enough, but there is more to it. One other factor is the wind.
If the wind is strongly blowing from the north or south, the waves washing up and down the beach, the water will be blown along the surface in the direction of the wind. On a strong north wind, for example, you'll see the water not moving just in and out, but also to the south. You'll see the water nearest the waterline running south, and the water just a little farther up the beach, making an arc along the lower slope. You'll get that slicing action, that can erode and wash the sand and other things towards the south on its way back into the south running current.
If you've ever stood in front of a cut or dune digging newly eroded coins and failed to get the coin on the first scoop and tried to find it again in the rushing water, you not find it again right away. Coins like that can be moved a good distance. Not only can the water bouncing off a cut wash a coin down the slope, but it might also wash the coin north or south as well.
It is worth doing the test for yourself. Stand in the rushing water and drop a coin, then try to find it with your metal detector. You might be able to track it. You will see how far the coin moved down the slope and how far it moved either to the north or south. That is good information. And it is another good reason to carry a test coin.
It might not be easy if you are not comfortable detecting in rushing water.
I frequently do that test when working in rushing water. You can find the coin once, and then let it go and try to find it again after another rush of water. Not only is it a good test to show you how the coins are being moved, but the knowledge might come in very handy if you miss or unintentionally drop a dug coin and have to try to find it again. You'll have a good idea how far and which direction the coin is likely to go. I highly recommend trying the experiment for yourself every once in a while.
There have also been a times when I couldn't find the coin again after the next rush of water. It is another good reason to carry a spare test coin or two.
I'll end there for today, and continue with Part IV in the future.
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| Source: SurfGuru.com. |
Sunday there were some really high King tides.
Monday the surf should be decreasing a little.
Good hunting,
TreasureGuide@comcast.net