Picture this: I’m perched near the top of a 10-metre mast high above the frigid waters of Lake Titicaca. The mast rises from a 15-metre-long reed boat that’s moored to a small jetty. At the end of the jetty sits a nine-ton stone, which several dozen people are preparing to manoeuvre onto the reed boat using ropes, wooden poles, and their bare hands. We are all in suspense, since none of us know exactly how this is going to go. Will the wooden beams spanning the gap between the jetty and the reed boat snap under the weight, sending the stone crashing into the water? Or will the stone make it onto the reed boat successfully, only to capsize or sink it with the added weight? There’s a lot at stake, especially for me, since I’m risking my life for a few photographs.
It’s moments like these when archaeology can seem more daredevil stunt than social science, but don’t let the adrenaline rush fool you: experimental archaeology is an important tool in figuring out how people did things in the past. It’s especially useful when studying an object still leaves questions about how it was made, used, or (in the case of our experiment) moved.
Our experiment arose from questions about how people brought extremely heavy stones to the Bolivian site of Tiwanaku in Pre-Columbian times. Tiwanaku was once the centre of a great Andean civilization, a city graced with grand ceremonial complexes and statues made from stones weighing multiple tons. Some of Tiwanaku’s most iconic monuments are made of andesite, a dense volcanic stone whose closest sources are 40 km away on the other side of Lake Titicaca. Most archaeologists believe that the people of Tiwanaku used large reed boats to carry andesite stones (some weighing over 30 tons) across the lake, since reed boats were the traditional watercraft of the region. However, believing a theory is a lot easier than showing how it could actually work, and that’s where experimental archaeology comes in.
A lot can go wrong in an archaeological experiment, so it’s good to do your research beforehand so you don’t leave too much to chance. Luckily, I’d written my undergraduate thesis about the Tiwanaku reed boat theory two years before the experiment and essentially planned the experiment step by step. My thesis caught the attention of Alexei Vranich, a recent PhD graduate from my university. Alexei had become director of archaeological investigations at Tiwanaku and was interested in testing out the reed boat theory full scale. He invited me to Bolivia to help with the experiment, and I naturally accepted.
The first thing we needed was a large reed boat. When you’re shopping for a reed boat you might as well go for the best, so we commissioned our reed boat from Paulino Esteban, a native Bolivian master builder who had made the Ra II and the Tigris for the famed Norwegian adventurer Thor Heyerdahl. It took 10 weeks for the Esteban family to harvest enough totora reeds, dry them out, and tie them into the bundles that formed the reed boat. It was fascinating to watch the family at work, and I photographed much of the process.
While the Esteban family worked on the boat, several of us went to find a suitable andesite stone for the experiment. We decided on a stone near the Bolivian lakeside city of Copacabana (the namesake for the Brazilian beach). The stone weighed an estimated 9 tons, making it roughly the same weight as one of Tiwanaku’s most famous statues, the Ponce Monolith. There were several complications, namely the rocky shoreline and the jumble of boulders that blocked the stone’s path to the water. We solved both issues with a team of 12 workers who moved the boulders into the water using ropes, levers, a traditional digging tool, and their collective strength. The result was a clear path and a brand new jetty that the reed boat could pull up alongside.
The reed boat was launched amid great fanfare; both the boat and the project were named Qala Yampu, meaning ‘stone boat’ in the local Aymara language. For the first few days of the voyage the boat experienced steering problems and veered badly off course, but after adding centreboards and altering the mast it sailed beautifully. Despite its bulky appearance, the boat had a remarkably shallow draught and was responsive even when there was little wind; at such times the crew would paddle, or punt where the waters were sufficiently shallow. With favourable winds the boat made reasonable time to Copacabana.
The crew moored the boat to the new jetty and joined the group that had gathered on land to move the stone onto the boat. The group included several sailors from the Bolivian Navy, whose commander had kindly allowed them to help with loading the stone (since their landlocked country faces few seaborne threats). As every nudge of the poles and heave of the rope brought the stone ever closer to the boat, I saw my opportunity and climbed up the mast.
At last the moment of truth had arrived. With my finger hovering over the shutter button, I looked down as the team prepared to roll the stone across the span of beams and onto the boat itself. I expected a violent jolt, perhaps one that would fling me off the mast and into the water. It all happened very quickly, and surprisingly gently, and then it was over; from my vantage point the much-anticipated shake felt like a medium-sized wave breaking against the boat. The stone now rested solidly on the boat, which still sat high in the water despite the extra weight. The air filled with cheers as we realized it actually worked.
Our experiment didn’t end with getting the stone onto the boat, but the rest seemed surprisingly easy after that. It took less than three days of sailing and paddling to reach our destination: the village of Santa Rosa, at the end of a peninsula not far from Tiwanaku. While the bottom reeds absorbed some water along the way, the waterline’s rise was less than expected and the boat remained strong; we estimated that the boat could have made the voyage with twice as heavy a stone. And unloading the stone turned out to be a lot simpler than loading: all it took was a group effort by the people of Santa Rosa and surrounding villages, who eagerly dragged the stone off the boat and back onto land.
Archaeological experiments like ours have it all: science, adventure, and a sense of what’s possible without modern technology. Thanks to our experiment, we now know something that archaeologists long suspected but had never proven before: that reed boats can carry multi-ton stones across Lake Titicaca.
You can check out Chris’s video of his adventures here: https://youtu.be/IoWBYyIRwoU. All images are his own.