Graduate student Jodi Preston stopped by the lab last week with a ballast stone from the Emanuel Point II site. In 1992, the Florida Division of Historical Resources found the remains of a Spanish galleon from Tristan de Luna’s 1559 expedition while conducting an underwater survey of the Pensacola Bay (Emanuel Point I). This is the oldest shipwreck in Florida and was Tristan de Luna’s first attempt at creating a colony in present day Florida. In total, de Luna had seven ships that were lost in a hurricane that hit the Pensacola area about a month after his arrival and therefore, his remaining vessels may still be in the Pensacola Bay. The University of West Florida worked with the Florida Division of Historic Resources to excavate the area, which was possible thanks to grant funds and UWF’s Archaeology Institute, and found two previously unknown shipwrecks. One of the shipwrecks dated to a period right before the Civil War and the other shipwreck (located about 400 meters west from the first Emanuel Point site) is associated with de Luna’s expeditions to colonize Florida. This specific site is being used to educate the public on Pensacola’s maritime and colonial history.
The ballast stone had an iron attachment and a ceramic sherd from a Spanish olive jar embedded on its side. Jodi planned to remove the iron portion and the ceramic sherd from the ballast stone and wanted a 3D scan of the whole object before removing each piece. The ballast stone along with its attachments measured around 30 cm long, which is large for our NextEngine Desktop 3D Scanner. Instead of using the NextEngine scanner, I opted for the Sense 3D scanner which has the ability to scan larger objects such as complete ceramic vessels, anchors and even people! We placed the ballast stone on a mount and as I held the Sense scanner Jodi manually rotated the mount. Unfortunately, we tried several times but could not produce a successful scan of the ballast stone with the Sense scanner. This may have been due to the irregular and asymmetrical shape of the ballast stone.
I decided to try using the NextEngine scanner instead. Normally, objects can be scanned twice with the NextEngine scanner and produce a complete digital model of an object. However, since the ballast stone was so large, it took three scans to completely record all of the information. We carefully placed the ballast stone horizontally on the mount. The NextEngine scanner recorded half of the ballast stone in the first scan and the other half in the second scan. For the third scan, we placed the ballast stone vertically on the mount and the scanner was able to record the entire object in one scan.
The large ballast stone turned out to be easier to scan than I expected. Each scan took about ten minutes, and Jodi and I spent thirty minutes total scanning the object. Once an artifact is scanned, the next step is to edit the object by trimming excess data and merging several models together. I spent Wednesday morning doing just that. I used ScanStudioHD software to trim extra data off the model and then used a yellow tag on the ballast stone as a merging point for the three models.
The trimming and merging process went smoothly. The last step in ScanStudio is to fuse the model which fills small holes and blends all of the models together to create a seamless digital image. This is where I ran into the most trouble. Every time I tried to fuse the model of the ballast stone, the software created more holes in the model rather than filling them. I tried to manually fill the holes but unfortunately, that did not work either. I contacted NextEngine support and via their Live Chat option on their software, a gentleman was able to guide me through the alternative process of fusing. I was able to use an option called “remesh” to fuse the object instead of the traditional fusing method. Finally, after struggling with the model all morning, NextEngine support was able to find a solution to help me. We now have a digital model (.stl and .u3d file, available via our GitHub repository) of the ballast stone as well as a scaled down (25%) printed version of it!
Our first 3D scan of an artifact recovered from an underwater archaeological context was a success, and we look forward to scanning more waterlogged artifacts this year!
For more information on the Emanuel Point sites and UWF’s underwater archaeology research, check out this short video: http://www.youtube.com/watch?v=VVOBjbJ9fJA