Monday, June 5, 2017

6/5/17 Report - Capitana Making Finds in New Salvage Season. How Coins Can Get Trapped On a Beach. Conservation of Wood Artifacts.

Written by the TreasureGuide for the exclusive use of

Musket Balls Found by the Crew of the Capitana.
Photo submitted by Captain Jonah Martinez
Not only has the hurricane season begun, but the Treasure Coast salvage season has also begun, and the finds have started.

I received the above photo and the following message from Captain Jonah.

First day on the Capitana was full of finds. Lots of musket balls, encrusted objects, and pottery shards.


I mentioned in the past how I once found five mercury dimes in one scoop.  I was going to explain that, but it took a while before I finally made the illustration.

It happened when there was a lot of coins on a small beach below an eroded cliff.  The water had been hitting the bank and washing out old coins.  I got a hit directly below the end of a fallen palm log (Orange spot), and  when I dug in and sifted the contents of my scoop there they were - five mercury dimes.

The find isn''t that impressive, but it does illustrate something that I talked about a lot.

The water was coming off of the face of the dunes fast enough to carry both sand and coins down the slope.  However, when the water hit the palm log, turbulence was created and the coins settled out and came to a rest in the area where the flow of the water was slowed.   That was an excellent example of a coin trap.  Also illustrated is what I often refer to as the trigger and settle points.

As long as the force of water is great enough it will carry objects.  More force is required to carry coins than sand.  When the force slows enough, both sand and coins will quit moving.  In this case the coins settled below the end of the log.

The fact that it happened to be five mercury dimes is partly coincidental.  They probably didn't wash out with the same retreating water, but probably got trapped one at a time.  Other coins could have been trapped at the same spot, even though other types of coins might have settled out higher or lower along the beach.  A lot of other finds were made at the same location that day and on other days.

I almost always check under and around object that might create a trap for small objects.  Rocks can create traps the same way.  I've found rings that got trapped by rocks.

You can actually create traps like that yourself.  I remember reading decades ago about a fellow that did that.  I believe I read it in Carter and Trevillian's book, Diamonds in the Surf.  I'm surprised that I remember the source.

It is always good to think about how and why finds ended up where they were found.


This isn't a new article but it is one that I don't remember seeing before.  It tells how difficult it is to preserve wood shipwreck artifacts for the long term.  Under normal circumstances even in wood that was thought to be well treated, acid continues to build up and damage wood.

Here are a couple of excerpts from the article on the deterioration of the wood on the Vasa.

Based on their findings, the researchers recommend strict regulation of a wooden marine artifact's environment. A relative humidity of 55 percent and a temperature of less than 68 degrees Fahrenheit (20 degrees Celsius) will slow migration of water and oxygen into wood and ensuing mechanical and chemical damage. The researchers also recommended replacing the 8,500 iron bolts holding the boat together -- inserted to replace the completely corroded original bolts -- with bolts made of an inert material. Eventually the infused iron in the wood might be rendered electrochemically inert with a chelating agent, and even extractable in an alkaline solution, but more work is needed to investigate this option.

"X-ray spectroscopy is almost uniquely suited to evaluating the chemistry of elements in situ in these artifacts. There is no doubt that the information we obtained would not have been available by any other method."

Here is the link to the article, if you want to learn more.


Hurricane season has arrived, but beach conditions have been very much unchanged lately.  We are still have a one-foot surf and no big surf can be found in the Treasure Coast predictions.

Happy hunting,