All shaft lines are designed on a basis of torque transmission from the motor/engine to the propeller. This torque rotates the propeller and create the thrust that generate the ship movement. For this reason torque must be transmitted ensuring the maximum propulsion efficiency.

In scenarios where there is no possibility to install a flanged shaft, or where conventional shaft connections result in a costly installation or cannot fulfil the requirements of the shaftline, Wärtsilä can offer the Hydraulic Coupling solution.

Hydraulic couplings are a very simple method of shaft connection. They reduce the requirement of shaft preparation due to no need for the use of keyways, tapers or thrust rings at the end of the shaft. Also ensures a safe transmission of torque to the propeller and support very high thrusts by friction force.

The hydraulic couplings are available in a wide range of sizes.

Hydraulic couplings consist of an internally tapered boss which presses over an externally tapered sleeve during its axial displacement. This contact forms the shrink pressing force. A good combination between sleeve, boss and shaft installation, in conjunction with the hydraulic injection method, allows the achievement of the desired torque an thrust transmission.

Wärtsilä hydraulic couplings are available in four executions.

Hydraulic couplings are made with high quality standard materials and comply with all requirements of the most exigent international societies standards. Also detailed manufacture and control procedures gives a perfect-ready to install product.

In case of installations under corrosive environments with coupling material, a external protection can be provided to avoid damages to the hydraulic coupling.


- Allow installations between a cylindrical shaft end to a cylindrical/flanged shaft end.
- Small gaps between connected shafts are accepted in coupling installation.
- Designed to ensure the shortest installation/un-installation time with the minimum resource.
- Equipped with a sealing system that allows an easy and clean installation/uninstallation process.
- Requires minimal shaft preparation.
- Avoid the risk of fretting and fatigue due to the lack of keyway stress raisers.
- No costly component substitution required throughout the whole life of the installation.
- Allows transmission of very high torques and thrusts.



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