WISCONSIN’S OLDEST SHIPWRECK

January 23, 2022

By James Heinz

Like real world archeologists, fictional archeologist Indiana Jones will cross the widest deserts, climb the highest mountains, hack his way through trackless jungles, sail the widest oceans, and fight his greatest nemesis, snakes, to find priceless historical artifacts. But Wisconsin’s own Indiana Jones, Tamara Thomsen, did not have to go quite so far to find a precious historical artifact.

She found it in her back yard.

It is the year 821 AD. Many major historical events occurred around that time. Charlemagne is crowned Emperor of the West by Pope Leo III. The great Angkor civilization begins in Southeast Asia. The Vikings sack London. And to the distress of generations of school children as yet unborn, syncopated algebra is invented.

In Wisconsin, the Effigy Mound culture is at its height, constructing its mounds around a body of water later known as Lake Mendota. And, one of their canoes sinks in Lake Mendota.

Fans of Great Lakes history know all about the birchbark canoe, a crucial mode of transport in both prehistoric and historic periods. Only the bark of the paper birch can be used to make a birch bark canoe. As the US Forest Service map shows, the paper birch does not grow naturally in much of southeastern Wisconsin. Native Americans needed a watercraft that they could fashion from local materials. So they invented the dugout canoe.

The dugout canoe is a universal human invention, and can be found all over the world anyplace there is water and trees. The oldest dugout canoe, found in the Netherlands, dates to 8.000 years ago. The oldest dugout canoe recovered in America is about 5,000 years old.

It is a simple but time consuming thing to make. Wikipedia describes the process:

“Construction of a dugout begins with the selection of a log of suitable dimensions. Sufficient wood needed to be removed to make the vessel relatively light in weight and buoyant, yet still strong enough to support the crew and cargo. Specific types of wood were often preferred based on their strength, durability, and density. The shape of the boat is then fashioned to minimize drag, with sharp ends at the bow and stern.”

“First, the bark is removed from the exterior. Before the appearance of metal tools, dugouts were hollowed out using controlled fires. The burnt wood was then removed using an adze. Another method using tools is to chop out parallel notches across the interior span of the wood, then split out and remove the wood from between the notches. Once hollowed out, the interior was dressed and smoothed out with a knife or adze. More primitive designs keep the tree’s original dimensions, with a round bottom.”

According to the Wisconsin Historical Society (WHS) website, State Underwater Archeologist Tamara Thomsen’s responsibilities with her Maritime Preservation and Archaeology Program are to preserve “Wisconsin’s historic shipwrecks and other underwater non-renewable cultural resources.” Tamara and her trusty sidekick Caitlin Zant are frequently called to investigate submerged resources, usually shipwrecks, which are found by others, usually scuba divers.

But in June of 2020 it was Tamara herself who found a shipwreck.

Tamara lives on Lake Mendota in Madison, and on June 11, 2020, she and friend Mallory Dragt were scuba diving off her property, testing a new diver propulsion vehicle. The visibility in Lake Mendota was very good that day, being 30 to 40 feet.

Mallory was leading when Tamara noticed her stop and hover over something on the bottom. At first the something looked like what most people would have dismissed as a log sticking out of the silt on the bottom. And in fact, that is what Tamara thought it was at first, due to its position.

Thirty seven dugout canoes have been found in Wisconsin lakes. In every other case, the canoes were found close to shore, within wading distance of the shoreline. Native Americans would submerge their canoes close to shore by placing rocks in the canoe to cause it to submerge to avoid ice damage.

But the supposed log sticking out of the silty muck at the bottom of Lake Mendota was on a slope 27 feet deep about one mile from shore, a much greater distance from shore than other recovered dugouts. As she examined it, Tamara realized that she was looking at an old dugout canoe.

And then Tamara and Mallory ran low on air and had to abort their dive.

Tamara made several dives over the next few months to photograph the canoe and to recover a sample of its wood for carbon dating. She also fanned away the silt, which at the down slope end of the canoe was 1.5 feet deep. At first only three feet of the canoe was visible, but when the silt was moved, the entire canoe was about 15 feet long.

Leaving the canoe exposed to the water without its protective silt covering would have exposed it to damage from algae and zebra mussels, so Tamara then fanned the silt back over it.

But just how old was it? Carbon 14 dating showed that the canoe was 1,200 years old, dated to the period 770 AD to 892 AD. Tamara realized this was Wisconsin’s oldest shipwreck.

Starting about the beginning of October 2020, Tamara and her boss Wisconsin State Archeologist Jim Skibo began to prepare to raise the canoe. By this time visibility in the lake was about six inches. An 80 year old volunteer named Russel Leitz, of the Wisconsin Underwater Archeology Association, did most of the diving over a four day period.

First, an airlift or water dredge was used to suck the silt from around the canoe and pump it up to a boat where it was run through a sieve in an attempt to recover any artifacts. Several pieces of wood were recovered. The canoe was sitting on the clay substrate of the lake, which had a strong suction effect. A water jet was used to remove silt from underneath the canoe and break the suction.

When the canoe had been liberated from its silty grave, they discovered that it was so light that it could be lifted with two fingers. Rebar was driven into the mud on each side of the canoe and rope was strung between the rebar to hold the canoe in place. In addition, four 45 pound sand bags were placed in the canoe to prevent it from floating away, just as the ancient Native Americans would have used rocks for the same purpose. A lifting sling made of canvas and spreader bars was placed under the canoe.

Finally on November 2, 2020, Tamara, Skibo, and some volunteers began to lift the canoe. The Dane County Sheriff’s Department loaned their dive team and boat to assist.

Tamara and five other divers descended to the canoe and turned it parallel to the slope. They then attached lift bags to the lifting sling under the canoe and slowly inflated the bags. The divers accompanied the canoe as it rose, making sure it ascended in a level position. When the lift bags reached the surface, the canoe was still four feet below the surface.

The Dane County Sheriff’s boat was used to tow the canoe most of the way to shore at a speed of less than one mile per hour. As they did so, the wind and the waves on the lake began to pick up. By the end of the day the waves had increased to 2 to 3 feet.

The divers swam and waded the canoe the last 100 yards to shore. The canoe was then placed on a padded aluminum plank and placed in a trailer for transportation to a conservation facility. The whole recovery process took four hours. The only artifacts recovered from the canoe were seven small stones used as fish net sinkers of a type associated with Great Lakes fishing.

The canoe was taken to a WHS preservation lab, where it was placed in a 300 gallon tank built by the lab itself. The tank was filled with tap water. At first, pool chemicals would be introduced into the tank to kill any organisms in the wood. Then the canoe would be lifted out, photographed, 3 D scanned and examined by experts

The cellular fluid in the wood cells had been replaced by lake water, and, as Skibo said, the only thing holding the canoe together is the water in its cells. For the next 2-3 years, increasing amounts of polyethylene glycol will be added to the water until the PEG level reaches 10 percent. The PEG will replace the water in the cells. After that the canoe will be freeze dried at minus 42 degrees Fahrenheit to remove any water that is left. The WHS hopes to complete the preservation process in time for the opening of their new museum in 2026.

The canoe, which is 15 feet long and 2.5 feet wide, was in such good shape that Skibo at first found it hard to believe that it was old as it turned out to be. Wuwm.com quoted him as saying:

“If something’s going to survive that way, it has to be constantly wet, constantly without light, so it must’ve been buried so living organisms can’t eat at it,” Skibo explains. “And oak is actually a very strong, stable wood, and also the fact that it had interior charring, I think leads to its pristine condition.”

Some mysteries concerning the canoe have not been explained. One is the fact that the canoe is made of white oak. Skibo said that white oak is dense, hard to work, and has a tendency to sink. Members of the Ho Chunk tribe, who were consulted and who witnessed the recovery, said that oak is a wood sacred to their tribe.

No cause for the sinking has been determined. The canoe sank on an even keel, since the seven net sinkers were still aboard. I speculate that the sinking of the boat may be due to the same weather conditions that developed as it was being recovered. A quick change of wind and increase in waves would have been enough to swamp a boat trying to return to shore.

Tamara believes that the only reason that one end of the canoe was exposed was that the silt was blown away by motorboat prop wash. Prop wash was responsible for the recovery of another canoe.

The Lake Mendota canoe is not the oldest dugout found in the state. That honor belongs to a canoe discovered in 1996 in Lake Mary in southwestern Kenosha County. According to a 2020 article in Wisconsin Archeologist magazine, in 1996 David Vrany’s motorboat prop wash uncovered a fragment of a dugout canoe lying on the bottom of the lake in front of his mother in law Reta Nagle’s property. Nagle and Vrany’s wife Jennifer recovered the fragment and preserved it by keeping it submerged in the lake.

They contacted the Kenosha Public Museum, who examined it and contacted Tamara‘s predecessor, David Cooper. He and his assistant Jeff Gray recovered the fragment and searched the area but found only one more fragment. In 1999 the Nagles found more canoe fragments. Cooper and Gray returned and recovered 23 more fragments despite conditions of zero visibility.

The fragments were oak and were dated to 1,850 years old plus or minus 60 years. The largest fragment was either the bow or stern and was the one Vrany found. It was 40 inches long and 20 inches wide. It had charring on the interior. It is believed that the canoe had been moved by either currents or ice from elsewhere within 4 years of its discovery and had only recently broken up.

The preservation process used was the same that will be used for the Lake Mendota canoe. It worked so well that the largest fragment is currently on display at the Kenosha Public Museum.

And if going to a museum to see a single dugout canoe interests you, then going to the Door County Maritime Museum (DCMM) will be twice as interesting, since it has two dugout canoes on display. In an email DCMM Collections Coordinator Brennan Christianson explains how the canoes came to be in their collection:

“Our museum is in possession of two dugout canoes. A recent assessment was made of our canoes, but we are still waiting to hear about carbon dating.

“One of our canoes is 144″ in length, 22″ in diameter, 20″ in height, and 12″ in wall depth. It was donated by Alice Hotz Apfelbach in 1974. This canoe was found on the shore of Europe Lake in Door County by Ferdinand Hotz, the donor’s father, in the 1920’s. It was on display at what is now the Death’s Door Maritime Museum until 1997, when it moved to the new facilities in Sturgeon Bay. A few attempts to stabilize the canoe have been performed including nailing 2x4s to both parts as well as reinforcing it with the use of foam and strapping.

“The second canoe is 182″ in length, 26″ in Diameter, 15″ in height, and 11″ in wall depth. It was donated by Fred and Rosemary Hansen in 1981. According to the donors, the canoe was recovered after high lake levels combined with a northeasterly storm uncovered the buried canoe near Braunsdorf beach in Door County. The donor believed that it had been buried in the sand since “before the turn of the century”. The canoe is in two pieces with one of the side walls having been separated at some point. It was mounted on the wall of what is now the Death’s Door Maritime Museum until 2018, when a roof leak flooded parts of the museum and caused the vessel to become fully waterlogged. It was then moved to Sturgeon Bay where it is currently on display next to the other canoe.”

I recently interviewed Amy Meyer of the Manitowoc County Historical Society (MCHS) about their dugout canoe. She told me that their canoe was recovered in 1979 in Gromski Lake in the Town of Newton in Manitowoc County by Bernard Novy. Novy called Ed Ehlert and Don Groll, a couple of board members of the MCHS, who examined it. The canoe had been filled with rocks to sink it in shallow water. The canoe is 12 feet long and is made of eastern white pine. It is an estimated 250 years old and is currently on display at the UW Green Bay-Manitowoc campus.

The Douglas County Historical Society has a dugout canoe in its possession, as does the Wisconsin Cranberry Discovery Center in Warren WI and the Wisconsin Maritime Museum, but requests for information about their canoes were not answered.

The making of dugout canoes is not a forgotten historical process. In 2016, students at UW Oshkosh made their own dugout canoe as part of an experimental archeology project. Their canoe is on display at the Oshkosh Public Museum. In 2019, Shawano resident Ben Thomas also made his own 12.5 foot long dugout canoe. He reported it took him 100 hours using hand tools.

So, like her fictional counterpart Indiana Jones, Tamara Thomsen found a priceless historical artifact, even if she didn’t have to leave her own backyard.

Hollywood has Indiana Jones. We have Wisconsen Thomsen.

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You can view Tamara Thomsen’s zoom lecture “What’s Canoe with You” on the Wisconsin Archaeology Facebook page at: https://wihist.org/canoe-webinar.

Photo at top of page:

Tamara Thomsen and her team raising the Lake Mendota canoe, November 2020. Wisconsin Historical Society photo.

Other Photos: