Krait'n, or sludge sledding

Sludge sledding (Krait'n in dialect) is a tradition during the Pinksterfeesten. It's held in the mud of the Wadden Sea / Eems during low tide.
A "krait" is a combination of a sled and a step.

In the old days fishermen used them to get over the mud to their fishingnets. But nowadays you can very well compete on these sleds.