The Proper Manufacturing of Mixed Ropes: An Inside Look at KATRADIS Technology

The Importance of Proper Rope Manufacturing

Synthetic rope manufacturing is a highly specialized process that combines proper selection of polymer materials, precision engineering and advanced processing methods to produce high-quality ropes for marine, industrial, and offshore applications. At KATRADIS Marine Ropes Industry, we utilize state-of-the-art technology and adhere to ISO standards to ensure that our ropes deliver maximum strength, durability, and safety.

The Perfect Blend: Polyolefin & Polyester fibers

IMPROVED mixed ropes combine the benefits of polyolefin fibers and polyester fibers in the outer layers into a balanced construction that capitalizes on the properties of both materials:

• Polyolefin: provides buoyancy and reduces weight. Our own NIKA-Steel® fibers developed and produced entirely in-house, are made from a special blend of Polypropylene, high density Polyethylene and UV stabilizer resulting in increased tenacity and durability compared to conventional polyolefin materials.
• Polyester: delivers durability, strength, and resistance to abrasion

The developed 24-strand configuration results in a rope that is not only lightweight and easy to handle, but also resilient to harsh maritime conditions, reducing the risk of accidents and increasing lifespan.

The Importance of Yarn Composition and Twisting Process in Rope Manufacturing

Yarn composition plays a critical role in the performance and durability of synthetic ropes. Proper twisting methods increase the yarn abrasion resistance, enhance energy absorption during dynamic loads, and extend the rope’s service life. This manufacturing process adheres to ISO 10556, which specifies the construction, testing, and performance characteristics of fiber ropes used in mooring and towing applications.

Twisting process of fibers into rope yarns

• Precision twisting machines to ensure optimal yarn twist per meter for strength and efficiency.
• UV stabilization for resistance to sunlight degradation.
• Uniformed yarn structure.

Rope yarn with Polyester fibers covering the polyolefin NIKA-Steel^® core fibers according to ISO 10556

(Fibre ropes of polyester/polyolefin dual fibres)

The proper braiding of rope structure

The good practice of the rope braiding ensures the rope’s internal and external fibers are uniformly aligned and tensioned. Proper and consistent laylength and braiding angles provide the required balance of the rope structure to operate in the mooring conditions and sudden loads.

Laylength: the linear distance required for a strand or braid to complete one full helical turn around the rope’s axis. Designing the effective laylength is a factor that can increase the durability of the rope.

The proper braiding laylength provides:

• Balanced distribution of loads evenly across all strands
• Better energy absorption during dynamic loads
• Increase of service life

Testing and Compliance acc. to MEG4 and IMO SOLAS

International guidelines such as MEG4 and IMO SOLAS circulars aim to enhance safety, performance, and longevity of mooring lines used on oil tankers, gas carriers, and terminals. All the required testing for compliance with MEG4 is performed in-house through our fully equipped Quality Department and expertized technical staff. Certification and Type Approval process of our ropes is under IACS classification society.

Testing Requirements for Mooring Lines

• Line Design Break Force (LDBF): The breaking strength of a spliced rope when tested according to CI1500
• Fiber Temperature break force: The strength of the fiber at various temperatures (-20°C to 80°C)
• Angled Break Force: The strength of the rope at 180° bending angle
• Angled Endurance: The remaining strength of the rope after 17,000 cycles at angled position
• Axial Compression fatigue: The remaining strength of the rope after 10,000 cycles in wet conditions

Angled Break Force as per MEG4 Testing in KATRADIS laboratory

Certification

When it comes to MEG4 compliance, it is very crucial for the end user to receive the correct certificates for both mooring lines and tails by the Rope Manufacturer.