Jacket Lifting Tool for offshore wind farm installation

Eager.one was awarded by Boskalis to design and fabricate a specialized Jacket Lifting Tool (JLT). The JLT was specifically designed for the installation project of an offshore wind farm near Taiwan. It will be used during loading, unloading and installation of 62 jackets.

During the installation work, the tool will be used for load-out from the quayside on board the heavy lift vessel. In addition, it will be deployed for lifting the jackets from the heavy lift vessel to the final installation position.

The jacket lifting tool measures approximately 8 by 6 by 5 meter and has a total working load limit (WLL) of 2,233 tons. The tool is designed with 6 clamps, that will jointly lift the jacket.

Jacket Lifting Tool overview

Jacket Lifting Tool, designed and constructed by Eager.one, including guide frame

To minimize tilt, regardless of the location of the Center of Gravity (CoG) on the jacket that needs to be installed, the JLT is equipped with a Center of Gravity adjustment system.

The complete hydraulic system, cameras and lighting are all powered by battery packs, which eliminates the need for an umbilical. However, the jacket lifting tool is equipped with a hydraulic umbilical to be able to release the JLT in case of emergencies.

Eager.one was responsible for the complete process of initial design, engineering, fabrication and overload testing of the jacket lifting tool. Furthermore, a guide frame and seafastening were included in this challenging design and construct project.

Guide frame

To ensure swift handling, the JLT uses a pre-mounted guide frame on the jacket flange. The guiding frame is mounted by means of non-marking guides and pins and kept in place by ballasting. Therefore, no clamps of other fixtures are required. At the same time, precision will be maintained in regard to alignment of the tool in relation to the jacket.

The JLT retrieves the guide frame during final installation of the jacket on the seabed. This eliminates the need for additional actions to retrieve the guide frame prior to turbine installation. As a result, the offshore jacket installation will be a remotely and unmanned operation.


guide frame on jacket flange

Guide frame is pre-mounted on jacket flange


JLT against bumper guide frame

JLT alongside guide frame

JLT attached to jacket

JLT attached to jacket


The jacket lifting tool will be held in position during transport at sea by means of seafastening. This seafastening consists of 4 stools with entry guides. These will be attached to the deck of the heavy lifting vessel, in which the support feet of the tool are placed.

Seafastening of the JLT is simultaneously used as an unload position for guide frames after retrieval. The seafastening supports maintenance activities and enables full functional testing.

jacket lifting tool in seafastening

Eager.one’s Jacket Lifting Tool in Seafastening


jacket lifting tool at construction site

JLT at construction site

Containerized Transport

One of the requirements for the design of the jacket lifting tool, was that the equipment could be transported in containers. Given the dimensions, this is obviously not possible in one piece. Therefore, the tool has been designed in a way that it can be disassembled in parts, that fit into standard shipping containers.

Jacket Lifting Tool in action

We are thrilled to share this impressive video. The video showcases the Bokalift 2, Boskalis’ largest crane vessel, in operation during the installation of turbine foundations for an offshore wind farm.

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