Abstract: A rubbery buckling-type marine fender such as cell-type hollow cylindrical marine fender, frustoconical-type hollow cylindrical marine fender, V-shaped marine fender or the like comprises a main rubber body portion, a securing flange portion, and a shock receiving portion, in which a rubber thickened region is formed in the inner peripheral surface of the main rubber body portion at a given position adjacent or close to a buckling point to prevent falling of reaction force during the buckling deformation.

Abstract: In a collapsible rubber dam, a fastening portion of a flexible rubber sheet body is fixed on an upper spillway portion of an arch type concrete dam or on a riverbed of a river in a curved form in the longitudinal direction of the body.

Abstract: A shock-absorber pad mount structure for mounting shock-absorber pads made of elastic material such as polyethylene or the like to a tip end portion of a fender.

Abstract: An apparatus for the adjustment of the water level in a lock comprises at least one fluid chamber arranged on a bottom or a bottom and a sidewall of a lock room between lock gates. The adjustment of the water level is performed by the supply and discharge of air in the fluid chamber through an air supply and discharge pipe.

Abstract: A flexible sheet dam is secured to the riverbed along two securing lines at upstream and downstream sides. In this dam, at least one concave and/or convex region is made in the plane of the riverbed between the two securing lines in a direction parallel to the securing lines, whereby the complete deflation of the dam can be attained without trouble.

Abstract: A flexible membraneous weir is disclosed. When air once filled in an air type flexible membrane weir is discharged in order to cause it to collapse, its membraneous wall is deformed in a V-shape at one portion in the river width direction, and a stream concentrates into this portion. However, the portion where the V-deformation will be formed is not certain. Therefore, it is required to reinforce the whole area of the river-bed and the river wall at the down stream side. In view of the foregoing, means is provided for starting V-deformation onto a bag-shaped member as a main body of the weir in a predetermined portion at a time when the bag-shaped member is collapse from its erected state. With this arrangement, the stream can be concentrated on the predetermined portion only. Therefore reinforcement is required only for a river-bed portion corresponding to this portion.

Abstract: A collapsible rubber dam secured to a riverbed portion and slope portions of both riverbanks is inflated and deflated by supply and discharge of a fluid. A pipe for supply and discharge of a fluid is communicated with the inside of the rubber dam from the shape portion of at least one riverbank except the riverbed portion securing the rubber dam. Preferably, the pipe for supply and discharge of the fluid is located in a region defined by a top end of the rubber dam located in the slope portion, a line connecting the top end of the rubber dam to substantially a middle position of a deflated width of the rubber dam at a toe of the slope portion, and a securing position of the rubber dam at the toe of the slope portion.