Shipwrecks in Flevoland's soil

Approximately 80 shipwrecks remain buried in the soil of Flevoland, according to the province. Since the reclamation of the Noordoostpolder, the Oostelijk Flevoland, and the Zuidelijk Flevoland, the province has inventoried 425 shipwrecks. Some of these remaining shipwrecks are located under agricultural land, where plowing can bring pieces of them to the surface.

World's largest dry ship cemetery

The Dutch heritage agency (RCE) counts more than 400 shipwrecks discovered and studied, referring to it as the world's largest dry ship cemetery. The exact total varies from inventory to inventory, which explains the "more than 400" rather than a firm number. The province states that nowhere else on land is there such a concentration of shipwrecks.

Comparing global shipwreck sites

Other land-based ship sites are much more modest: 16 shipwrecks in Dreumel, 31 in Yenikapi in Turkey, 39 in the old port of Pisa. Added together, they make 86 shipwrecks, barely more than a fifth of the Flevoland count. Researchers also enter these shipwrecks into the maritime database MaSS. It welcomed 122 Flevoland shipwrecks in 2020, then 152 more in February 2024, giving a total of 274 shipwrecks, nearly two-thirds of the provincial count.

Formation of Flevoland's shipwrecks

The closure dike, the Afsluitdijk, completed in 1932, separated the Zuiderzee from the North Sea. It then became necessary to drain large areas, starting with the Noordoostpolder in 1942, then the Oostelijk Flevoland and the Zuidelijk Flevoland. The ships lying at the bottom for centuries emerged with it, and some lay just below the surface of the ground. These hulls did not sink by chance.

Causes of shipwrecks in the area

These are mainly fishing boats and inland navigation ships, and the Flevoland shipwrecks often measure about 20 meters. When they sank, many of them partially sank into the seabed, and then a thick layer of silt covered what was above. The shallow waters, sandbanks, silted channels and violent storms trapped ships between 1200 and 1900.

Preserving shipwrecks on land

A shipwreck that ends up dry quickly deteriorates. After the drying out, the groundwater level has dropped significantly, and some hulls have partially emerged from the water. However, the fungi that degrade wood need air, which is almost absent under water. The solution is therefore to keep the wood saturated with water, even if it means locally raising the groundwater level.

Inkuilen method for preservation

The method is called inkuilen: the shipwreck is covered with soil, wrapped in agricultural plastic, and then covered with soil again. On a watership in the Oostelijk Flevoland, sunk around 1600, the perforated plastic is covered with about 1 meter of soil seeded with grass. The film slows evaporation during dry periods, while rain and the rise in groundwater maintain moisture.

Limitations of the preservation method

A layer of clay under the hull prevents water from seeping downward, and the condition of the wood is checked every year. Of the 80 shipwrecks, 21 are protected by inkuilen and 16 are covered with a layer of soil to prevent plowing. This makes 37 hulls under protection out of about 80. The process has its limits: it only works if an impermeable layer is under the shipwreck, and when nothing is enough, it is necessary to excavate to save the information.

Discovering unknown shipwrecks

Remains of shipwrecks regularly resurface with plowing, and an unknown number of hulls have not yet been discovered. Maritime archaeologist Yftinus van Popta suspects that there are dozens more. The tools exist: ground radar, magnetometer, resistivity measurements, infrared. But geophysics is far from always working.

Marking and managing shipwrecks

A cargo of stones, for example, sends a good signal. The wet wood in the wet clay, on the other hand, remains very difficult to detect. On site, blue and white poles adorned with a small red boat indicate shipwrecks; after twenty years, they have rusted and were replaced around 2023. The province also recommends, with every excavation, to consider the possibility of a chance discovery. Future construction sites are therefore affected in the same way as plows.

A discovered shipwreck in Noordoostpolder

In the spring of 2016, plowing hit wooden pieces near Rutten in the Noordoostpolder. The shipwreck was covered with soil, then excavated by the University of Groningen in the summer of 2018. Length estimates range from 30 to 35 meters, with about 30 meters in the final report, for 7 meters in width. The hull was broken in two along its entire length.

Details of the 1715 shipwreck

The shipwreck dates back to around 1715-1720. Archaeologists believe it to be an English merchant ship. It would be of the type straatvaarder, designed to cross the Strait of Gibraltar towards the Mediterranean. They nicknamed it "Queen Anne" because of tin spoons bearing the arms of Queen England. Today, this ship is no longer under a field. The excavation lasted four months, entirely by hand, and the wooden remains were placed along the edge of the Kuinderbos.

Artifacts recovered from the shipwreck

More than 1,000 objects were found, including cannons, cannonballs, pepper grains, and Mediterranean fruits. This shipwreck was dismantled rather than left in the ground, which distinguishes it from the approximately 80 that still await.

Historical context of shipwrecks in the area

During the 700 years of existence of the Zuiderzee, archaeologists estimate that 3,000 to 4,000 ships sank on the entire seabed. The inventory of the polders therefore only covers part of this, and not all the ships that sank have been found.