Double slip joint

modular design

The high demand for clean energy is driving a growth in the number and size of offshore wind turbines. These larger turbines require heavier lifts and higher reaches, which often exceed the current crane capacities of jack-up vessels. 

In addition, pile connections are not currently future proof, presenting a number of challenges. This includes the long curing time required for the grout, extended installation times and the high maintenance cost of bolted flanges. The required manual work also carries additional safety risks. 

Therefore, KCI have developed the Double Slip Joint (DSJ) to provide an alternative. It is quicker to install and reduces the pile weight thanks to its innovative underwater connec¬tion.

Watch the DSJ video here



  • Creates a simple connection (no grouts or bolts).

  • Facilitates quick installation.

  • The TP is instantly stable on the pile.

  • No personnel are required to work on the TP.

  • The connection can be underwater (creating a reduction in the pile weight).

  •  Entirely maintenance-free.

  • Anodes are located at an ideal depth.



Material: St355

No diameter limit

H/D ratio ~ 0.5

The DSJ is a simple, robust and stable con¬nection. It enables the modular design of a com¬plete foundation and turbine. The foundation can typically be installed 30% faster than by conventional methods using flanges. The manufac¬turing costs of foundations are also lower, especially where larger turbines are concerned. 

No additional investments are required by an organisa¬tion, as a result of a reduction in the pile weight supply chain and necessary installation equipment. More flexibil¬ity and higher employability of the installation fleet can therefore be predicted for future extra-large foundation projects.


KCI offers complete foundations featuring the DSJ as an integrated product. This avoids issues related to conventional grouted connec¬tions or bolted flanges, and makes installation quick and straightforward, providing a permanent robust connection.