dredger extensionThe dredger extension is an add-on for the regular intact stability extension of DELFTship™. It can be used to calculate the intact stability of dredgers, but also for other vessels with open cargo holds, like open-top container ships for example.

Dredgers carry their cargo in a hopper, which often is open at the top. If the cargo is considered liquid it is allowed to spill over the hoppers spilling edges, thus decreasing the vessels displacement when the heeling or trim angle increases. When the ship heels further then sea water may enter either through the hoppers overflows or over the spilling edges. The hopper extension takes all this into account.


  • Easy but detailed definition of complex hopper shapes.
  • Automatic extraction of the spilling edges from the hopper. Compared to the traditional way of manually defining the margin line (spilling edge) points this is far less sensitive to errors. The software ensures that the correct spilling edges are used at any time, even after a modification to the hull form or hopper geometry.
  • HopperInput of overflows. Points defining the overflow can be specified manually, or generated automatically in case of circular overflows.
  • Calculation of intact stability using either the lost-buoyancy or added weight method.
  • Stability calculations for both liquid or solid state of the spoil.
  • Add a layer of water on top of either liquid or solid spoil