IMH Takes to the Skies

In the northeast, IMH is working with state agencies and university students to document coastal archaeological sites in tidal environments, and coastal sites that have become exposed as a result of storms.

Not to be confused with Autonomous Underwater Vehicle (AUV), IMH recently volunteered its DJI Phantom 3 Professional, an Unmanned Aerial Vehicle (UAV), aka “drone”, to document shipwrecks exposed following offshore hurricanes and heavy beach erosion on Salisbury and Seabrook Beach in Massachusetts and New Hampshire:

http://www.newburyportnews.com/news/local_news/remnants-of-centuries-old-shipwreck-wash-ashore-at-salisbury-beach/article_7d6e2781-d7a5-5235-9f80-223908847145.html

http://www.seacoastonline.com/article/20151105/NEWS/151109434

State agencies such as the Massachusetts Board of Underwater Archaeology, the New Hampshire Division of Historical Resources, and Maine Historic Preservation Commission, occasionally receive notification from the public of exposed shipwrecks and coastal prehistoric sites, but almost always lack the resources and manpower to conduct site visits and gather information that can be used to document exposed archaeological sites, and inform decision-making and support preservation efforts. Here is where IMH (and UAVs) can play an important role in supporting the documentation and preservation of maritime heritage.

Case in point, in October-November 2015, following hurricanes Joaquin and Kate, beachgoers reported to state agencies that large shipwreck fragments were exposed or had washed up on Salisbury and Seabrook Beach. The agencies then contacted me and asked if I could make a site visit and evaluation. My response was, of course! After a short 20 minute drive from home, I was able to quickly deploy the UAV and document the wreckage within 15 minutes. The Phantom 3 has an on-board Global Positioning System (GPS) that provides excellent location data for the UAV, but not necessarily the subject matter of the image (i.e., the wreckage). Therefore, I also collected Ground Control Points (GCPs) using a sub-decimeter GPS, which allowed me to correctly orient and scale the wreck debris. After a few perspective shots to provide context, a close-up overhead shot, and about an hour of post-processing on the computer back at the office, “Voila!” – the result was a high-resolution, accurate site plan, allowing for direct measurement from the photograph:

Salisbury Beach Wreckage, Perspective View: Perspective view of wreckage on Salisbury Beach.Salisbury Beach Wreckage, Perspective View: Perspective view of wreckage on Salisbury Beach.Salisbury Beach Wreckage, Overhead View: Overhead perspective view of wreckage on Salisbury Beach.Salisbury Beach Wreckage, Overhead View: Overhead perspective view of wreckage on Salisbury Beach.

 

 

 

 

 

 

 

 

Salisbury Beach Wreckage, Detail View: Overhead of wreck debris without scale, north orientation, and lens distortion correction.Salisbury Beach Wreckage, Detail View: Overhead of wreck debris without scale, north orientation, and lens distortion correction.

Salisbury Beach Wreckage, Scaled Detail View: Lens distortion removed and color corrected. Image was scaled and oriented using sub-decimeter (&lt;10 cm) GPS ground control points.Salisbury Beach Wreckage, Scaled Detail View: Lens distortion removed and color corrected. Image was scaled and oriented using sub-decimeter (<10 cm) GPS ground control points.

 

 

 

 

 

 

 

 

 

 

 

The imagery not only provided documentation for posterity, but also supported decision-making for those government agencies charged with the protection and conservation of maritime heritage in the following ways:

  1. Determined that the wreckage was squarely in the jurisdiction of Massachusetts, and not in New Hampshire, as originally reported.
  2. The debris was clearly a large fragment that was disarticulated (or dislodged) from a shipwreck site as a result of recent storm, tidal, and wave activity, and was not in situ (in its original location), or representative of a shipwreck site.
  3. Provided site formation process insights, in that within two days the wreckage had migrated some 300 feet south from its original reported location, and had broken off from what was once a much larger hull fragment.
  4. Allowed state agencies to record site location information into cultural resource databases, make decisions about the historical significance and conservation potential of the reported finds, and alerted coastal resource managers of the presence of heritage and shipwreck sites in the area.
  5. Confirmed that UAVs offer a cost effective, rapid response, and accurate means of documenting maritime heritage sites.

There were no identifying marks or historical artifacts to indicate which ship the wreckage is associated with, but it is generally thought that the fragment is from the wreck of Jennie M. Carter, a three-masted schooner that beached in a storm in 1894 en route from Rockland, Maine to New York with a cargo of stone. The wreck fragment appears to be coincident with 19th-century schooner construction, so this wreckage is perhaps associated with Jennie M. Carter, but could not be confirmed. Any future survey work, such as wood species and dendrochronology sampling could support further vessel identification and dates of ship construction or repair.

Jennie M. Carter, Wreck: Early 20th-century postcard of the wreck Jennie M. Carter.Jennie M. Carter, Wreck: Early 20th-century postcard of the wreck Jennie M. Carter.

Based on the aerial imagery provided by IMH, the decision at the state level was ultimately to not recover the debris or conduct any further investigation of the wreckage. There is generally little appetite for or availability of public funds to document and conserve artifacts of this nature, and therefore the “do-nothing” response at the local, state and federal levels, beyond basic recordation is perhaps appropriate but also not surprising. However, when responsibly and safely deployed, the UAV is certainly one tool that can be used effectively by organizations such as IMH to raise awareness of and document and preserve maritime heritage in a way that also supports, encourages, and engages our government and citizens to do the same.

In 2016, IMH will be using its UAV to document maritime heritage from an entirely new perspective. I will be taking to the skies to photograph a variety of maritime archaeological sites and built-heritage sites throughout New England. Check back to the IMH website for updates on IMH's UAV work!