Dredger and method for dredging

摘要

The invention has for its object to provide a dredger for selectively dredging only the contaminated upper layer (26) of a bottom located under water. For this purpose the invention provides a dredger comprising a ladder (3) supported by a vessel, at least one endless bucket chain (16) with a series of buckets (7) which is carried by the ladder and guided round at least two turn-over members (27,14) and comprising guide means (17) for guiding the bottom part of the bucket chain in a substantially straight path. The invention also provides a method for selectively dredging only the contaminated upper layer, which method has the feature that a thin layer of a bottom located under water is scraped off, while the bottom part of the bucket chain is held substantially parallel to the bottom surface and while the dredger is warped sideways. <IMAGE>