The Dredging Contractor Sea Curtain System (DCSCS) has been developed to provide a solution for major dredging contractors where highly durable but versatile and variable curtains are required.
This configuration of curtain is typically used for spreader pontoon and bucket and backhoe dredge frames. It is constructed as follows:
- A float assembly configured from rotationally moulded foam filled float elements (upto 750mm diameter) through bolted to a top tension member configured from reinforced conveyor belting. The use of this float assembly configuration provides the following advantages: The rotationally moulded foam filled floats; have a high resistance to impact, however, where floats are damaged for example by water craft trying to cross they can be replaced individually in situ without the need to remove a section of curtain and they are UV resistant and extremely durable and not damaged by periodic water blasting where marine growth accumulation needs to be removed. The use of a conveyor belt top tension member; allows the integration of extremely high longitudinal tensile strength without the addition of sewn on webbing etc for example the standard at 500mm has a longitudinal strength rating of 2700kN. Whilst 500mm is the standard depth this may be varied up to 1800mm overall depth to, limit spread of surface or near surface suspended solids, provide a combined sediment and oil pollution boom and limit entanglement by surface debris such as logs or water craft.
- Note an alternative float assembly can be constructed from dredge pipe
- The DCSCS skirt system is usually manufactured from woven high strength PET or PP geo-textiles which is then manually attached to the belting under the float line. The detachable curtain provides the following benefits: the skirts can be easily replaced when either damaged or entrained with contaminated material where cleaning is not a practical option and where a deeper or shallower curtain is required. The skirts may be removed from the float assembly allowing a manageable repair without having to handle the float assembly through a sewing machine and permits a variation in skirt depth from project to project without the expense of replacing the entire float assembly.
- The DCSCS is usually ballasted using either heavy galvanized or stud link chain. Provision is made at the bottom of the skirt for the ballast to be shackled to the bottom of the skirt at 500mm intervals (webbing and grommets) or 1000mm “D” ring attachment plates.