Trade ships have sailed in and out of the port of Kampen for centuries. In 2012, three medieval shipwrecks were found nearby, in the IJssel. The main wreck, the cog, will be salvaged February 10, 2016. Kennislink spoke to a maritime archaeologist about this so-called IJsselkogge.
The cog is a medieval ship type, which was frequently used by traders between Hanseatic cities because of its space capacity. These cities had made a special alliance to promote mutual trade. Read more about the construction of cogs and the Hanseatic League in part three of the cog triptych.
Rijkswaterstaat's normal policy is to investigate shipwrecks underwater and then leave them behind. But because of the deepening of the IJssel, the cog has to give way at Kampen and Rijkswaterstaat is paying for the extensive research and salvage of the medieval ship.
Archaeologists have been investigating underwater since the discovery. Because of the location of the cog, which is near the harbor of Kampen together with two smaller boats, they think that the ships were deliberately sunk in the fifteenth century. So conscious water management in the Middle Ages? It looks like it.
It is known that at the beginning of the fifteenth century the IJssel was silting up, so that large ships could no longer sail through the shallow river. The sunken ships could influence the current and scour the riverbed to get more depth.
Water management
André van Holk, professor of Maritime Archeology at the University of Groningen, is part of the team of experts on the excavation. “I am indirectly involved in the research, but I find this theory very plausible. Medieval people might not have had our technological knowledge, but they weren't stupid at all. They have been intervening in nature to get things done since the eleventh century, with the construction of dikes and locks. The location of those three wrecks so close together indicates conscious intervention.”
Now that the IJsselkogge is in the way of the current water management, it will be raised and can be further investigated on land. This is a unique opportunity. “It is not the first cog that has been found in the Netherlands and certainly not the only one; at least fifteen cogs have been found in Flevoland, several of which have contents. But what makes the IJsselkogge special – in addition to the fact that the construction appears to be complete – is the inner paneling that is still present. We really don't know anything about that yet!"
Warship
To their surprise, underwater archaeologists found a galley with a cupola furnace and pots and pans in the cog. This cast some doubt on the water management theory of the deliberately sunk ships. Why weren't they removed? Van Holk “I don't think that's so strange because demolishing an oven is quite a hassle. It also appears that the pots and pans belong to the ship, but the investigation is still in full swing. In addition to these finds, the ship was empty when it was sunk, so the water management theory will remain valid for the time being.”
There was no more cargo in the cog, which underpins the water management theory. It's just a shame, because cargo and personal objects tell an interesting story. “Personal objects can always be found in a ship that has sunk in action. Leather shoes, pots and pans, eating utensils, that sort of thing. A leper clapper has even been found in a wreckage near Almere. So we know there was a leper on board there.”
The oven, on the other hand, is also a special find, but the reason for its presence is still a mystery, explains Van Holk. “Normally, the place to cook on a cog was a lot easier. A wooden box with sand in it, covered with tiles, usually served as a fire pit. Why this cog had an oven is still a mystery. It is possible that the cog eventually served as a warship. A large capacity furnace can of course feed more mouths – i.e. soldiers – than a simple fire pit.”
Woodworm
The IJsselkogge near Kampen is a 'youngster'. Denrochronological research, in which scientists can determine how old the wood is on the basis of growth rings, shows that the wood of the IJsselkogge was cut in the first half of the fifteenth century. The ship type is still used in that period, but has already passed its peak. Its bigger brother, the Hulk, was more popular because of its even larger cargo space. The oak ships did not sail long. Van Holk:“A cog lasted about 25 years. Then they were exhausted by intensive use and too much eaten by shipworm. Ships were regularly repaired in those 25 years. The rotten bits were chiseled out and covered with new wood. This method of repair, i.e. with a patchwork of small pieces of wood instead of completely new planks, is what the English called Dutchmen .”