Wreck Diving Solves Archaeological Mystery

by Tamara Thomsen:

2 wreck divers

Photo Credit: Tamara Thomsen

On November 2, 1905 the goliath, wooden steamer Appomattox attempted to navigate into the harbor at Milwaukee’s North Point through fog and smoke so dense that the ship was enveloped in darkness. For nearly two weeks efforts were made to release the steamer, but she was eventually abandoned and broke up. Her machinery was subsequently salvaged, and today she lies in 20 feet of water only 150 yards off Atwater Beach just north of Milwaukee, Wisconsin, her hull broken and scattered across the sandy bottom.

To many divers, a broken hull like that of the Appomattox holds less appeal compared to more intact vessels – even ships that are entirely stripped of rigging, gear, and artifacts. But to an underwater archaeologist or any diver with an analytical eye, these sites present a prime opportunity to study and learn about wooden vessel construction. The advantage of broken hulls like the Appomattox’s is they offer a view of many construction details that are hidden in more intact vessels. Like a fingerprint in a forensic investigation, construction features identified in the scattered remains can offer means of identifying a shipbuilder.

The Appomattox was launched in 1896 by master shipbuilder James Davidson, and was the world’s largest wooden bulk steamer ever built. Davidson’s career straddled the transformation from wooden to steel hull construction on the Great Lakes, but Davidson continued to push the engineering window to extend length limits of wooden ship construction at a time when many of his contemporaries switched to building with iron and steel. He utilized wide steel arches to strengthen his hulls (called hogging trusses), which ran the length of his hulls longitudinally. Internally in his hulls, Davidson utilized a lattice-like iron basket frame attached to the vessels structural frames. This prevented the wooden planking from separating and opening up due to the burden of stress and work in waves, and under cargo weight.

In 2003, archaeologists from Wisconsin Historical Society’s Maritime Preservation and Archaeology Program along with many local volunteer divers endeavored to piece together the history of the Appomattox. Like virtually assembling an expansive puzzle on the bottom of Lake Michigan, nearly all pieces of her 319-foot hull were located and documented in the survey. However, one gargantuan piece of the vessel was missing – the entire length of the starboard side of the ship. When I visited the Appomattox to photograph the wreck, I heard stories of another local wreck previously identified in the early 1980’s by local divers as the steamer Josephine. It was located just inshore, so we plunged into the cool waters of Lake Michigan once again to survey this vessel.

By examining the dimensions and spacing of diagnostic timbers on the Josephine, and the absence of a keel, it was determined that the “Josephine” was in fact the missing starboard section from the Appomattox shipwreck! Our careful observations led to the conclusion that this was not a separate shipwreck as was previously thought. Not only were the two ships united as one, but archaeological clues found in the “Josephine” wreckage allowed us to discover an important missing characteristic to Davidson’s vessel construction.

The presence of both interior and exterior steel arches spanning the entire length of the vessel’s sides provided evidence for Davidson’s use of hull-strengthening techniques. After this discovery on the so-called Josephine, reinvestigation of the main wreckage site yielded previously undiscovered remnants of an interior hogging truss. This is the first time this construction technique has been archaeologically recorded for one of Davidson’s vessels.

Much of what we know of Davidson’s work we have learned from the archaeological record, which exists on the lakebed today. The discovery that two shipwrecks were actually fragments of the same ship combined with careful surveys of the wreck at both locations provided important historical evidence for Davidson’s reinforced hull construction. As a result of this work, the Appomattox wreck site has been listed on the National Register of Historic Places.

Tamara ThomsenTamara Thomsen is a Maritime Archaeologist with Wisconsin Historical Society’s Maritime Preservation and Archaeology program. Her research has resulted in thirty-eight Great Lakes shipwrecks added to the National Register of Historic Places. She has participated as a photographer, researcher, and research diver on projects ranging from the USS Monitor with NOAA National Marine Sanctuaries to RMS Titanic with Woods Hole Oceanographic Institution. She has been an active TDI Instructor since 1996 and is a 2014 inductee into the Women Diver’s Hall of Fame.

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