TWS invests in series pull-in systems

Tension Winding Solutions, originally a subsidiary specializing in rentals at DROMEC, is investing in a new series of pull-in systems.

Gerrit Drost says,
“With TWS, we aim to continue innovating and distinguishing ourselves in equipment for offshore applications. Having successfully completed two projects, the pull-in operation at the Luchterduinen wind farm in the North Sea and Windplan Blauw in Urk, in collaboration with a reputable offshore contractor, we now aim to contribute to a sustainable future with these new systems!”

Pull-In System

TWS intends to rent out pull-in systems for various operations at wind farms and provide coaching for operators. The pull-in system is used to pull power and data cables from the vessel into the wind turbine. It’s a complex tool specifically developed by DROMEC Winches for this purpose. Specific variations have been designed for different continental regions. For instance, additional safety standards such as Loler and Puwer are required in the waters of the United Kingdom.

Constant Tension

Before installing the wind turbine on the platform, the pull-in operation takes place. The cables are pulled from the vessel through the seabed onto the platform using the pull-in system under constant tension. This means the cable is always kept at a predetermined tension, even in the event of unexpected increases or decreases in cable force, preventing cable overload. This special tool has a nominal pulling force of 10 tons. The force is applied through friction between the rope and a special capstan head. By adjusting the number of windings in combination with a tensioner, the pulling force is ensured up to a holding force of 12 tons.

TWS plans to deploy the pull-in systems in sets of 4 to 10.

Gerrit Drost adds,
“With DROMEC, we can strengthen each other in collaboration. If a system fails during the pull-in operation, as a rental company, we can immediately arrange a backup. We also assess on-site whether any improvements can be made. With DROMEC, we can quickly adapt and create innovative solutions for each other. From TWS’s perspective, once the market experiences these pull-in systems, they become indispensable. Since the operation can only be performed during certain times of the year due to weather conditions, we also aim to focus more on operator training. The right expertise benefits both ways. Equipment remains in better condition, ensuring continuity in operations, which is crucial. Our focus is more on the service and maintenance of the product. Eventually, we’d like to build a test tower to simulate real-life pull-in operations, enabling us to expand rentals to Germany, Denmark, Belgium, and France!”

Automatic Tensioning

The system operates with automatic tensioning. A tensioner synchronized with the capstan head ensures there is always sufficient tension between the tensioner and the capstan. This guarantees the pulling force through the capstan without requiring a person to continuously hold the slack end. The system is electrically powered, very compact, with a low weight of 550 kg. Without the detachable tensioner, it weighs 475 kg. Once the operation is complete, the system is moved to the next wind turbine platform, making it highly suitable for rental by TWS.

Pieter, engineer at DROMEC, comments,
“This compact pull-in system is a user-friendly tool that can be installed on any platform for pull-in operations. The combination of low weight with high force, using advanced control software, is a real time-saver for the customer. The system can be used both in a standing and hanging position. Several improvements have been made for the new series, such as the nominal pulling force and the hard-anodized capstan head, which is more resistant to corrosion. The frame is also more user-friendly, with an integrated lifting eye and additional guide bracket, allowing the cable to be wound on and off at a 70-degree angle.”

DROMEC Winches constructs winch system for megadoor Smulders UK

Smulders is an international steel construction company operating in the onshore and offshore sectors. For a new production facility in Newcastle, DROMEC Winches at the request of ASAV lifting- and hoisting technology has developed an advanced winch system for an impressive megadoor.


The impressive production facility stands at a height of 36 meters and a width of 47.5 meters, equipped with a megadoor operated by two powerful winches on each side. The megadoor consists of steel panels divided into sections, hanging from the steel structure. The advanced winch systems effortlessly lift the panels upward or lower them downward, ensuring perfect alignment during opening and closing. Additionally, the winches can be operated independently for added safety or in case of a malfunction. The winch system has the capacity to hoist a weight of 135 tons on a single cable.

Winch System

The two winches are strategically positioned on either side of the megadoor. The cable runs up and over multiple pulleys on one side and descends to a fixed point on the other side. The system is precisely mirrored on the opposite side. Both winches operate synchronously to maintain the desired speed during the opening and closing of the megadoor. The winch system has a pulling force of 19 tons and can handle peak loads of up to 38 tons. In situations where the winches need to bear the weight or during emergencies, the system operates at a lower speed to ensure safety.


Jesper Becks from Smulders:
“The installation of the megadoor was a complex process that required a combination of technical expertise and practical experience. Given our specialization in steel construction, we relied on DROMEC as a reliable partner for the supply and installation of the electromechanical components. DROMEC handled the entire process, from the engineering of the winches and lifting mechanism to the installation. Transparency, flexibility, and safety were paramount at every step. Thanks to DROMEC’s technical knowledge and flexibility, the installation of this impressive 135-ton megadoor went smoothly. The successful and safe completion of the installation is a significant milestone in this project.”



Both winches can be easily operated using a control panel or a button. The control system includes a switch to detect whether the doors are in the upper or lower position. Sensors acting as limit switch are installed at both the top and bottom of the door. Furthermore, the door is equipped with a wind sensor to prevent opening in strong winds. DROMEC has also incorporated a built-in functionality to seamlessly switch from the regular power supply to a generator if necessary.


Pieter van Roekel from DROMEC:
“The Smulders project showcases a combination of precision and weight within a timeframe of approximately 15 weeks. We have made every effort to fully support Smulders throughout the process. The installation and tensioning of the cables were carried out by our experienced team in collaboration with our partners at TWS.”