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  • Client:
    Boskalis Westminster
  • Duration:
    2 Days
  • Shift Type:
    Days
  • Year:
    2016
  • location:
    Portsmouth, UK
  • AREA:
    54m³
  • SOLUTION:
    Bacel Hardfoam

Project Goal:

DWG Resins were approached by Boskalis Westminster a Dutch / English dredging company to see if we were able to provide a product that was able to prevent water from entering 3 Spuds ( 30mm thick x 900mm diameter x 28 metres long hollow tubes with a pointed end ).

The spuds are used to drop through the deck of dredging barges to anchor and stabilise them in relation to the seabed and to give a level platform from which to work. The spuds are lifted prior to moving to a new area to commence dredging again so any added weight is a great issue. They had been having problems with the added weight of water seeping into the spuds, and in some cases this was around 7 to 8 tonnes extra, which increase the strain on all the lifting equipment.

One of the main issues was the dredging barge was unable to sail in to shallow water within the harbour so all equipment had to be demountable and could be craned of the vehicle onto a small barge and then be transported out to deeper water and again craned on the the dredging barge. All the material is stored and transported in 1000 litre IBC’s ( the size of a euro pallet 1200mm x 1000mm ) with a maximum weight of 1200kg. The pumping unit is of a similar size and weighs around 400 kg and the power for the entire pumping process is provided by a compressor.

Project description:

DWG Resins were able to offer the Bacel Hardfoam super lightweight engineering foam grout that would add around 2 tonnes to the spuds overall weight far less than the water within the spuds at present plus an added advantage was the material inhibits further corrosion of most metals when in contact but will not cause any buoyancy problems with the spuds when they are dropped into position. DWG Resins asked the client to cut small round holes ( 50/60mm ) at each end of the spuds and weld in 2 x internally threaded steel inserts to accept a 1.5 “ BSP threaded connector, this was to allow a valve and cam lock connection to be made to the foaming gun. The spuds were tipped up to release the trapped water via the holes cut in the ends after which the Bacel hardfoam was pumped into the empty spud displacing any residual liquid which was expelled along with the air via the vent point at the other end of the spud and pumped until the foam was seen exiting the spud which meant that the spud was completely filled, the spud is then pressurised for a predetermined time.

All valves are then closed and the material is allowed to harden and the internal pressure within the spud was allowed to dissipate over an hour.

After it is was determined that the pressure was gone the valve connectors from both the fill point and the vent point were removed and a plate was welded back over sealing the spud from all external influences.

The complete pumping process took less than one hour per spud after installation of the 1.5” BSP internally threaded steel inserts.