The wreck site IJsselkogge was found in 2011 with the use of sonar at the bottom of the river IJssel, near Kampen, in the Netherlands. Most of the wreck is buried in up to four meters of sand, with only the starboard side exposed and detectable by sonar.
The wreck is one of a few cogs found in Northern Europe, but is very unique to do the preserved condition of the vessel. The wreck lies in the fresh water of the river IJssel, which means that it is not at risk from the shipworm, teredo navalis, which can cause high levels of destruction in wrecks located in salt water. The wreck is also almost completely buried in the river bed, which contributed to the high level of preservation.
There are two features of IJsselkogge which are of high interest to researchers, a wooden winch on the foredeck, and remnants of the rigging terminals of the standing rigging along the mast. It is rare for either to be found at wreck sites.
The cog was presumably sunk to increase the silting of the river IJssel, as two more wrecks were found extremely close by, and the vessel does not contain any cargo, or any remains indicating that she was transporting anything at all.
In March 2013, the decision was made by the organization in charge of studying the wreck that efforts would be made to raise IJsselkogge.
The wreck site dubbed IJsselkogge is that of a cog from the first half of the 15th century. A cog is a type of ship that first appeared in the tenth century in Northern Europe, and was widely used from the twelfth century on. The cog was primarily associated with seagoing trade in medieval Europe, and especially within the Hanseatic League. Cogs were single-masted ships with a single square-rigged sail. They were spacious, and relatively inexpensive, but sturdy enough to be seaworthy on the open ocean. This became necessary when certain vital shallow-water trading routes in Northern Europe became silted up by the twelfth century.
The wreck of the cog found near Kampen in the river IJssel, so named IJsselkogge is estimated to be 20 meters in length, and 8 meters wide.