Cable Hang-Off System with Polyurethane Sealing Components

The Cable Hang-Off System with Polyurethane Sealing Components is a critical subsea power cable securing and sealing mechanism designed specifically for offshore wind farms, oil and gas platforms, and Floating Production Storage and Offloading (FPSO) units.

Typically installed at the transition piece (TP) or atop the J-Tube of monopiles and jacket foundations, this system supports the full self-weight and dynamic tension of subsea power cables and umbilicals. By incorporating high-performance, custom-cast polyurethane sealing modules, the system guarantees long-term structural anchoring, effective environmental isolation, and exceptional water tightness in demanding marine environments.

System Structure and Working Principle

The system operates by seamlessly combining mechanical load-bearing capacity with elastomeric sealing performance:

Main Hang-Off Body & Flange: Fabricated from high-strength low-alloy steel or super duplex stainless steel, treated with hot-dip galvanizing or marine-grade anti-corrosion coatings. It secures directly to the J-Tube top flange or cable deck of the offshore structure.

Cable Clamping Mechanism: Engages and locks the cable's outer armor wires, effectively transferring the tension and gravity load of the hanging subsea cable onto the platform structure, thereby preventing structural strain on internal conductors.

Polyurethane Sealing Modules: Positioned at the entry interface of the J-Tube, the custom polyether/polyester polyurethane elastomeric gland seals block seawater, salt mist, and debris. Their high dynamic resilience absorbs vortex-induced vibrations (VIV) caused by marine currents, preventing localized stress concentrations and outer sheath abrasion.

Key Advantages of Polyurethane Sealing Components

Superior Wear and Tear Resistance: Features high tear strength and a low coefficient of friction, accommodating micro-displacements of the cable under wave action without degradation or sealing failure.

Exceptional Hydrolysis and Salt Spray Resistance: Formulated specifically for subsea immersion, ensuring immunity to seawater degradation and offering a design service life exceeding 25 years.

Low Compression Set: High elastic recovery ensures that the sealing gland maintains constant sealing pre-tightening pressure under long-term compression, eliminating the need for frequent field maintenance.

Customizable Engineering Fit: Precision-molded to accommodate single-core, three-core, or export cables, as well as umbilical systems of varying external diameters.

Primary Applications of Cable Hang-Off System

Offshore Wind Farms: Securing and sealing inter-array cables and export cables at the J-Tube / Monopile top entry.

Offshore Oil & Gas / FPSO Platforms: Topside hang-off and sealing for subsea umbilical, riser, and power cables.

Subsea Cable Protection Assemblies: Integrated with bend restrictors and armor clamps to form an end-to-end cable protection chain from the seabed to the topside deck.

Technical Specifications & Customization

Polyurethane Hardness: Shore 70A to Shore 95A (Tailored to load and seal requirements)

Corrosion Protection Level: Compliant with ISO 12944 C5-M / CX extreme marine exposure

Design Service Life: 25 Years

Testing & Certification: Hydrostatic pressure testing, tensile load testing, and third-party marine classification certification supported.