8/3/15 Report - Layers of Sand Holding Coins. Classification Of Objects On A Beach. Hurricane Vulnerable Cities.

Written by the TreasureGuide for the exclusive use of treasurebeachesreport.blogspot.com.

Beach Illustration.

The thing that I want to point out using this illustration is the layers shown both under the shallow water and under the berm crest.

You can sometimes clearly observe different layers of sand when you dig a target.   You'll see one color of sand over another.  Sometimes the different layers are the same color but one layer will be more course or fine than the other layer.

There are times when coins and things wash up with sand.  When that happens, the coins will be in that layer of sand.  That layer can then either get covered up by newer layers or eroded away.

Once you find a coin in a layer of sand there will probably be others in the same layer.  You can then  look for the layer containing the coins.  That layer might be covered by other layers or exposed by erosion.

So when you find a coin that has washed up, pay attention to the type of sand it was found in.

A lot of times I've dug coins that were right at the dividing point between two layers of sand.  I've found that a lot.

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How are birds and treasure coins alike?  They flock together.

You might remember me saying this before.  Birds of a feather flock together.  So do treasures.

When you find one of a particular kind, there is a good chance you'll find more around the same area.

That was demonstrated very well this year when the guys on the salvage boat Capitana found hundreds of musket balls.  They went many days without finding any, then all of a sudden found hundreds together.  It wasn't an accident.

The longer things have been in the ocean and the more they have been affected by moving water, the more they are classified or grouped together.  One of the most repeated myths of treasure hunting is that items are classified by weight.  As I've said before, a ton of Styrofoam will still float, and so will an ocean liner made out of steel.  It isn't weight so much as it is density, and also, by shape.  In my opinion both of those are big determinants of how items are classified by moving water.

Things that are recently dropped or are dropped on the high and dry beach won't be sorted.  It takes time and force.  So the longer things are exposed to more force the more classification you will see.

It is a lot easier to learn about classification where a lot of targets are lost.   Where there are few targets you won't see the patterns nearly as easily.  I was fortunate to be able to quickly learn about classification when I first started detecting in South Florida where you have a high population density of beach goers.

Objects don't have to be identical to be grouped or clustered together.  They just have to be similar - in density and size and shape.  The more similar they are the more they will tend to cluster.

People often don't take shape into account, but shape is important too.  I've talked before about how different shaped objects move differently.  I've even reported my own experiments.  Using a splash test, I predicted how different size and shaped sinkers moved different amounts when hit by splash of water.  Round objects moved more on a sand surface than flat coin-like objects of the same density and weight.  When objects are the same density and shape, larger and heavier objects were moved less.

There are also objects that trap air.  Those are mostly more recent objects such as watches, for example.  Watches move easily and tend to stay in higher and looser sand because the trapped air makes them act as if they are less dense.  The bands, if still present, also affects how watches move in the water.

Of course, sometimes items are found together because they were lost together, such as coin spills.  Take a look at items found together to see if you can get any idea about how long ago they were lost.  Corrosion or patinas will sometimes give you some idea.

If you find an item take a look at it to see if it provides any clues.  If it looks like it was lost a good time ago and has been subject to moving water, be sure to look for other similar items in the same area.  That is one of the main things you can do to hunt more effectively and efficiently.  Get as much information out of finds as you can.

When you see one Robin, there is a good chance that there will be a flock.

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If you find a medallion take a look at the edge of the medal.  Often you'll find helpful markings there.

Medallion Showing Marks On Edge.

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Here is a listing of the cities or towns that are most vulnerable to hurricanes.



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The Treausure Coast will have another week or so of one to two foot surf, so no big changes.

Happy hunting,
TreasureGuide@comcast.net

7/6/15 Report - Corroded Silver Coins. Corrosion As A Clue. Coins and Layers of Sand.

Written by the TreasureGuide for the exclusive use of treasurebeachesreport.blogspot.com.

 As you know finds come in a variety of conditions.  Some come up looking like they were lost yesterday and some barely survive.

Of course some were lost just yesterday, but some that were lost long ago, still look very good, while others that aren't as old have deteriorated to near nothing.

Silver shipwreck cobs are the same way.  Some show great full detail, while others are worn away to just a fraction of what they once were. The two sides of the same coin can be very different too.

It is very common for cobs that are found on an ocean beach to have lost as much as one third of there original weight.

As I said yesterday, I've been looking at some old finds that I never really looked at very well.  In that group were a good number of Rosies and Mercs in various conditions.

Here are two of the Mercury dimes in not terrible condition.

As you probably know, silver tends to turn black, especially when it has been in sea water.

On the other hand, silver dimes that I've found in cold fresh water lakes up North, have a more gun metal blue patina and very little erosion.

The two mercury dimes above were found on Florida ocean beaches.  I don't recall exactly where.

The second one (1934) is more corroded than the top one (1941) and shows sand still adhering to the surface.

The third is also a silver dime.  This one is much more corroded.   You can't tell if it is a Rosie or Merc or what.  It does appear to be a dime though.

Notice that it also has sand still adhering firmly to the surface.  That tends to cause a mottled rough surface that is very commonly seen on more corroded silver dimes that come from an ocean beach.

I went through several that looked like this yesterday, as well as some that were worn paper thin and some that were worn completely through in some places.

Those that were paper thin were either still round though.

Some reales show the same type of corrosion.  This half reale was found at Jupiter and has one very crisp side.  The side shown in the photo was completely covered with a thick shell crust when it was found.  The other side had no sand sticking to it and that side was completely visible when dug, but the details aren't as crisp.  It seems the sand shell on the one side protected and maintained the surface of the reale.  After the sand shell was cleaned off using Muriatic acid, I saw what you see here.

Exactly how one side was so heavily encrusted and the other side not at all, I don't know.  My theory is that it rested in the sand dunes for hundreds of years unmoved.  It is hard to explain how one side attracted sand and the other side not at all.  Other cobs have been found paper thin, but still showing good detail.

Here is an uncleaned dime, which seems to have lost silver in a way that is relatively unusual for a silver dime.  They often maintain the round shape even when severely corroded.  I've seen very few silver dimes that have lost the round shape like this one.

On this one you can still make out some of the detail on the side shown in the photo.  There is no detail that can be seen on the other side.

If you look at the amount of wear, or lack of wear on a piece of silver, you might get some clue about where it has been.  If you can figure out where they have been, then you will better know where to look to find more.

Unfortunately I don't know now where these dimes came from.

I do know exactly where the half reale came from, and I am pretty sure that it just washed out of a sand dune before it was dug up.  I suspect that it was in the dune undisturbed for hundreds of years.  Undoubtedly in that time it was washed over by sea water at least a few times.  Perhaps that accounts for how one side got encrusted but not the other.

My main point today is that if you pay attention to your finds, you might get some clue to the source and therefore know where to look for more.

I suspect that coins that lose a lot of material, like the irregular shaped dime shown above, at some point was in the churning sand in the shallow water.  In contrast, I am pretty sure that was not the case for the half reale.

As a side note, I've coins found in acidic black soil around mangrove trees really corrode and dissolve.

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A few days ago you saw in this blog how old shipwreck coins and items were found using blowers near shore.  A good bit of sand had to be moved to expose those items.  There are two ways that such items would have ended up under feet of sand.

Items that were lost during a hurricane might have been lost when tons of sand had just been removed and found their way down to near bedrock right away.

The other way is that items could be lost on top of layers of sand, either in the water or on the beach or on the dunes, and then gradually found their way to lower levels over the years and centuries.

Each time a layer is removed, the objects go deeper.  Sometimes they are covered again by new layers and remain there under the new layers until new erosion removes sand to deeper depths.

And of course there are times when coins and things are washed up with the new sand.  The coins that most recently washed up will then be in layers of sand above those that were in layers that previously eroded.

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It looks like the surf on the Treasure Coast will be just a touch bigger this week, but not very much at all - it is still a smooth surf.

Happy hunting,
Treasureguide@comcast.net

9/4/14 Report - How Coins and Rings Sink In Beach Sand. Targets Only Sink As Far As The Disturbed Layer.

Written by the TreasureGuide for the exclusive use of treasurebeachesreport.BlogSpot.com.

Same Cup of Water and Sand
Shown Yesterday.

Just in:  I have some great new pictures of treasure ship finds sent by Captain Jonah!   Probably tomorrow.


I accidentally did an ingenious experiment.  I should probably call it an observation rather than an experiment.  I'll get back to that in just a minute. 

I always enjoy receiving emails from this blog's readers.  They are an educated and intelligent bunch.

Yesterday I talked about how objects of interest sink in sand.  I received an email from Bill F., who has a degree in physical oceanography and did his undergrad thesis on beach erosion at Ponce Inlet.  

Here is some of what Bill said.

1)  The finer the sand particle, the flatter the beach
2)  The faster the current, the bigger the particles which are moved
3)  As you show, without wave/water energy, objects don't settle on their own.
4)  The heavier/denser an object, the less likely it is to move horizontally.
5)  Shape makes a difference.

Thanks Bill!   Those are some good points to remember.


Above is a picture of the same cup that I showed yesterday.  The ring and coin in this cup never sank so much as a micro inch while it sat undisturbed.   That clearly demonstrates one thing Bill said -  without wave/water energy, objects don't settle on their own. 

I decided to see what it actually takes for objects to sink in the sand.  I put my hand over the cup and moved the cup in a semi-circular motion so that the water moved.  When the water moved the very top layer of sand lifted and the suspended sand moved with the water while the objects pretty much stayed in place.  When I stopped, a little sand covered the objects, but very little.  With gentle only the sand above the green line moved.  This is important, and I'll get back to it.

When the objects got covered there were a couple of ways I could tell how deeply they got covered.  You'll notice that the surface of the sand in the cup (below the yellow line) is not exactly horizontal. 
A perfectly circular even motion moved the water so that the sand remained level across the cup, but by moving in a more jerky  manner resulted in the sand moving from one side to the other of the cup to the other. 

I could see how deeply the objects got buried either by sticking my finger in and finding the objects or I tilting the cup and moving it so that the sand then uncovered one side and one object.   I could then see where the previously covered object had stopped sinking.  

Here is an important point.  The amount of sand that moved when I moved the cup was directly related to how fast I moved the cup and therefore how fast the water moved. 

I had no idea how important it was going to be for me to be able to see through the container when I started this experiment. 

When moving the cup gently, a small amount of sand moved - only a thin layer.  Approximately the amount of sand above the green line which I drew on the picture of the cup moved when I moved the cup gently.  The top of that layer moved the most, decreasing as the moving layer got deeper until there was no suspension and movement of sand at all.

The fastest moving sand was clearly suspended, and the grains appeared farther apart than the grains that were lower in the moving layer, which moved more slowly and less overall.

 How deep do you think the objects sank in the sand when the cup was moved gently?   Now this is an important principle.  The objects sank to the surface of the layer of stable sand, and then stayed there.

I recalled how many times in the past few years that I dug an object and found it on the surface of a lower layer of sand.  If you go back through this blog I'm sure you can find that.  Often the lower layer was a different color or texture.  Often it was a layer composed of course shells.

That might not be surprising finding, but it sure was interesting to see.  I could keep the water moving at a relatively slow rate and no more sand would be suspended or moved.  No matter how long I kept the water moving at the same speed, the objects sank no deeper than to the surface of the layer of stable sand.

I know this is not a highly controlled experiment and what happens on a beach will be somewhat different, but in I think this principle will hold.  Just like in the previous report, the objects did not sink into the undisturbed sand no matter how long they sat there in the cup.  In this demonstration the objects did not sink into undisturbed sand even though they did sink through the suspended moving sand.

Here are a few observations that held up all through these demonstrations with the moving cup.

 (1) Only a relatively thin layer of sand was disturbed by the moving water. 
(2)  When the cup and water was moved more forcefully, a larger layer of sand was moved.
(3)  The speed of the sand decreased in the moving layer of sand from top to bottom until there was no movement at the bottom of the layer.

At first I moved the cup gently and only the layer above he green line moved, but when I moved the cup more forcefully, then the sand moved as deep as the light blue line, and that is where the objects ended up, and when I moved it even more forcefully, the sand moved as deeply as the dark blue line, and that is about where the objects ended up.

On the beach, different storms will disturb deeper layers of sand allowing targets to sink deeper.  They will then often be covered again by incoming sand. 

In this demonstration I'm only addressing sinking targets, which occurs primarily when the trigger point for sand is reached but not the trigger point for targets. 

This simple experiment has many limitations, but it reveals some important principles that I've observed in operation on the beach.  I reasoned that objects in deeper layers of undisturbed sand would remain in place, but with this demonstration I observed it and am much more certain of it.

Another thing I observed with this little experiment is how it is only suspended sand that moves.  I could see this on the beach just yesterday.  The waves were crashing on a sand bar.  In front of the sand bar was what I might call a flat topped creeping sand bar.  You could see a clear edge of a layer of sand that was moving from the crash zone towards shore.  The crash would suspend sand, and then that suspended sand would be washed ahead in the surge.

Where the sand was suspended, you couldn't see through the water.  That makes sense.  But closer to shore, where there was a dip beyond the creeping sand bar, and the water there was clear.  That is where I found a couple of relatively new coins that had not yet been covered by the incoming tide and creeping sand bar. 

As the tide comes in, the area where the waves crash and most sand is suspended closer to shore.  Obviously that means that a greater area of sand is affected.  The crash zone changes and the area of surge comes in and then goes out again.

If you've spent much time down in the Fort Lauderdale and Miami area, you know that they have much more calm water than we do.  Many days the shallow water sits still almost like you are in a bath tub, especially before the sun starts to heat things up.   The shallow water on the Treasure Coast seldom has that kind of flat water even when the surf is down to one foot.  That small difference in roughness appears to make a big difference in the average sink rate of targets.  They'll stay in detector range down there a lot longer than on the Treasure Coast.  Couple that with the absolute number of people and what they wear and there is an even bigger difference between South Florida and the Treasure Coast.  Bottom conditions are very different.

Well, I'll quit there for today.  This is getting long.  The principles demonstrated are important and help explain how things settle and therefore how and where things will be found.  I know that I did not address all of the relevant factors and situations. 

I'll do some more experiments someday to help answer some of the remaining questions.

I'm sure some of you will find this post tedious although several of you used the +1 button to indicate that you particularly liked the previous post.  For my own purposes and understanding, I'm glad I did the demonstration.


There are no storms to watch in the Atlantic right now.

On the Treasure Coast we still have a one foot surf and will continue to have a calm surf for at least a few more days.

Happy hunting,
Treasureguide@Comcast.net