The HAMMOCK Seafastening for Monopiles

17-10-2018 Rotterdam

The HAMMOCK Seafastening for Monopiles

While lying in a hammock in the sun, have you ever realized that the hammock supports your body from left to right. Not only for your adult sized body, but there is the same support when a child uses the same hammock.

A similar support is now possible for monopiles of all sizes in transit to a wind farm offshore. TWD introduces a monopile seafastening that accommodates all foundations, including those used today up to the 11m diameter in the foreseeable future without any changes to the support structure.

The innovative seafastening consists of two supports fixed to the deck of the vessel either transversally, across the vessel, or longitudinally, from bow to stern. One side of the support is fixed rigidly upright while the opposite side frame is hinged at the base. Between the two sides a special designed rope is slung in a cross-over pattern, designed to avoid lateral movement of the monopile.

When loading the monopile on to the vessel the hinged support frame is held open and as the ropes take the weight of the monopile this support automatically closes. Contact pads on the upper horizontal part of the frame will come to rest on the monopile securing the lateral support.
Stacking a second frame on top of bottom support frame is possible. The upper support frame is then equipped with a hydraulically operated lifting arm to raise the rope to one side to give access to the monopile below.

The whole seafastening uses less steel than conventional designs saving on cost and weight. Mobilization and demobilization time between projects will also be faster and easier, giving you more time to relax in your own hammock in the sun.

Please contact us for inquiries and more information about the hammock seafastening design.


We are specialized in creating custom-designed tools and structures that allow you to perform projects safely and on time. You can regard TWD as your problem solver. The reliable partner that creates functional and creative solutions, regardless of the time frame, or the complexity of the challenge. Our goal is to reinforce your project team’s capabilities and complement them where required, so together we can achieve a successful project execution.

Our thorough knowledge of structural and mechanical engineering, hydro-dynamics, finite element methods and design for offshore conditions, enables us to develop practical solutions to meet the wide variety of your demands.

With the substantial knowledge of optimal installation methods and the proven engineering approach in the offshore wind industry, TWD can now also assist in delivering turnkey tools and products, such as this innovative seafastening design.