| 摘要 |
Device for protecting a section of ground which is located underwater from erosion, at the same time serving to promote and permanently maintain silting beneath this device itself, as well as a method for positioning a Dutch mattress of this nature in a simple manner, using a small working boat, and only a few personnel, without there being any need for sea-going pontoons, cranes and rock embankments. Figure 4 shows how a mattress of this nature is dragged into position in co-operation with the tide and in the folded state, by means of a block which for this purpose is temporarily attached to the anchorage. <IMAGE>
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