How to dress your dredge pump for success

C. de Groot Double walled dredge pump, 1970

Sometimes, we are just reinventing the wheel. In 1970, when we were still this company ‘C. de Groot’, we delivered a dry soil transfer pumping station ‘GP6’ to Volker Stevin. Special requirement of the client, was to have a double walled dredge pump installed. Because of the pressurised outer cover, the cast inner pump wall had less stress and lasted longer. Even more, in case the inner wall became damaged, it leaked into the gap between inner and outer wall. No mixture spilled into the pump room. Double walled pumps were already around in the ‘60s, but always in cast material. C. de Groot was the first to build one from steel plates. In effect, we were the inventor of the double walled dredge pump. Since 1970, a lot of high performance or safety demanding pumps have been built this way. Not only by us, but later by many other manufacturers1 also.

Now, we might upturn history again, as we developed a new outer cover for dredge pumps2. This time, the outer cover can be literally tailored to your pump. It is of woven flexible material, that can be zipped around any new or existing pump. Well, it involves some modifications of the steel pump doors, but it should fit on any size or design. It will withstand the pressures occurring during a pump burst, when the cast casing is worn through.

We went through several interesting design and test cycles, before we finally had a solution, that ticked all the marks:

  • Light weight
  • Easy access
  • Water tight
  • Safe and reliable
  • Durable
  • Retrofit

Added advantages are: less weight on the dredge pump is more cargo in the hopper. And as fabric can be slid through the gap between lowest point of the pump and the bottom plate of the hull, the pump will stay at the lowest possible location, favouring a good NPSHa.

Ewout van Duursen will explain more about how we achieved confidence in this concept, on the CEDA Dredging Days3. We did a lot of practical tests and thereby gained operational experience on handling a real life DynaCover. We discovered that the handling is much easier than a steel cover, indeed. As for the experiments: stay tuned, because the presentation will involve some Mythbuster style research, rather than academic experiments. In a way, fitting between the other interesting more scientific presentations of the Friday morning session of 11:00.

In line with the practical nature of this research, we have a sample of a DynaCover with us, for you to judge yourself4. It will provide you a tangible glimpse of the future, where double walled dredge pumps look like this:

Damen DynaCover double walled dredge pump, 2017


  1. Double walled dredge pump for longer life, Ports & Dredging #73, p13, IHC, 1971
  2. Innovative outer pump cover zipped on
  3. Presentation session Ewout van Duursen
  4. Damen booth

See also

CEDA Dredging Days