Scoop dredger, model, c. 1800, after a design of 1627. Silting was a major problem in Dutch harbours, especially after 1600 as ships became larger and draughts deeper. To keep the harbours accessible numerous inventions were proposed in the 17th century. One example is this scoop dredger. The twelve 'scoops' were each operated by one man using the hoists on the raised deck. The silt was dumped in the two barges.