Custom-engineered cable constructions combining power, control, data, fibre optics and mechanical strength—with multi-service umbilicals available when hydraulic, pneumatic or fluid hoses are also required.
One engineered connection for multiple services
Offshore and subsea equipment rarely needs a cable to perform only one function. A single connection may have to supply electrical power, carry control and instrumentation signals, transmit video or high-bandwidth optical data, withstand deployment loads and remain manageable on a reel, winch, sheave or tether management system. Some systems must also transfer hydraulic fluid, air, gas, water, hot water or chemicals.
Fibron designs and manufactures bespoke composite cables and umbilicals for subsea, offshore and other harsh-environment applications. Each construction is developed around the complete operating duty rather than selected from a standard catalogue. Electrical, optical, mechanical and fluid-transfer requirements can therefore be considered as parts of one integrated system.
Fibron can support the complete development process, from initial feasibility and cable architecture through prototype manufacture, qualification, termination, testing and production supply.
What is a composite cable?
A composite cable combines two or more functional elements within one overall cable construction. Depending on the elements included and the terminology used in a particular industry, it may also be described as a hybrid cable, electro-optical cable, electro-mechanical cable or electro-opto-mechanical (EOM) cable.
A bespoke subsea composite cable may contain:
- low-, medium- or high-voltage power conductors;
- control and instrumentation cores;
- individually or collectively screened pairs and quads;
- data transmission elements;
- coaxial components for video or specialist signals;
- single-mode or multimode optical fibres;
- earth conductors and drain wires;
- water-blocking materials, fillers and bedding;
- steel-wire armour or high-performance synthetic-fibre strength members;
- protective braids and an application-specific outer sheath.
Combining these elements can reduce the number of separate connections required between two pieces of equipment. It may also help control overall diameter, weight, handling complexity and the number of penetrators, connectors or termination interfaces within the wider system.
Industry terminology is not completely uniform. An electrical and optical construction may be called either a composite or hybrid cable, while a construction that also carries substantial tensile load may be described as electro-mechanical or electro-opto-mechanical. Where cables are laid up with hydraulic, pneumatic or fluid hoses, the completed multi-service assembly is generally described as an umbilical.
Umbilicals containing cables and hoses
Fibron’s capability extends beyond all-cable composite constructions. Application-specific hoses can be incorporated alongside electrical and fibre-optic cables to create a complete subsea or offshore umbilical.
Depending on the application, these hoses may transfer:
- hydraulic control or operating fluid;
- compressed air or breathing gas;
- gas-reclaim services;
- water or hot water;
- liquid chemicals;
- other compatible process or service fluids.
This makes it possible to provide electrical power, control signals, communications, video, optical data and fluid services through one managed connection. Products of this type may also be described as electro-hydraulic umbilicals, hydraulic control umbilicals, cable-and-hose umbilicals or multi-service umbilicals.
The hose specification must be developed around more than working pressure. Relevant variables can include the transported medium, chemical compatibility, internal bore and required flow, proof pressure, resistance to external collapse at depth, temperature, minimum bend radius, cyclic duty and the type of end fitting or hydraulic coupling required. Cable elements, optical fibres, hoses and strength members also respond differently to tension, bending and pressure. Their position within the cross-section, lay direction, lay length and relationship with surrounding reinforcement and sheathing therefore have to be engineered as a complete system. This is particularly important for dynamically deployed umbilicals that will be repeatedly reeled, bent or loaded.
Application-led composite cable design
The optimum construction depends on how the cable or umbilical will be installed, handled and operated throughout its service life. Early engineering involvement is valuable because cable diameter, bend radius, weight, connector selection, winch geometry and termination design are interdependent.
Electrical power and control
Power conductor design may be influenced by voltage, maximum and continuous current, duty cycle, acceptable voltage drop, conductor resistance, insulation system and thermal behaviour. The current-carrying capacity of a cable stored in multiple layers on a winch can differ significantly from its capacity when fully deployed in water.
Control and instrumentation circuits may require individual or collective screening, controlled capacitance, defined impedance, appropriate earthing and protection against crosstalk or electromagnetic interference. High-voltage constructions may introduce additional requirements for insulation thickness, electric-field control, partial-discharge performance and termination design.
Mechanical performance
Mechanical requirements may include working load, design load, minimum breaking load, axial stiffness, elongation, torsional behaviour, resistance to rotation, static and dynamic bend radius, bend stiffness, crush resistance, clamping loads, abrasion and impact.
The load path into the end termination is as important as the strength of the cable body. Armour wires or synthetic strength members must be terminated so that tensile forces are transferred effectively without imposing damaging strain on electrical conductors, optical fibres or hoses.
Data and fibre-optic transmission
Data elements can include screened twisted pairs, quads, coaxial components and optical fibres. Selection depends on transmission distance, data rate, protocol, bandwidth and the electrical-noise environment.
For fibre-optic components, the design may need to address fibre type and count, allowable strain, attenuation, bend performance, excess fibre length, routing through breakouts and the optical connector or penetrator arrangement at each end.
Diameter, weight and buoyancy
Outer diameter and weight affect vehicle payload, drag, catenary behaviour, reel capacity and the forces generated during deployment and recovery. Submerged weight and buoyancy may also influence the manoeuvrability of an ROV tether, the stability of a tow cable or the suspended load carried by a launch and recovery system.
Where a particular buoyancy characteristic is required, it should be treated as part of the initial cable architecture rather than as an addition after the mechanical and electrical design has been fixed.
Deployment and handling
The cable must be compatible with the complete handling system, including reels, winches, drums, sheaves, level-wind mechanisms, overboarding arrangements and tether management systems. Drum diameter, sheave diameter, fleet angle, tension control, storage conditions and the anticipated number of operating cycles can all affect cable life.
Environmental inputs can include water depth and external pressure, seawater exposure, temperature, UV exposure in topside sections, hydrolysis resistance, oils, fuels, chemicals, seabed contact, abrasive surfaces and the intended storage and service life. Fibron’s design process considers these electrical, optical and mechanical variables together rather than treating them as independent specifications.
Static, dynamic and load-bearing constructions
A static subsea cable may remain largely stationary after installation, but it can still experience installation tension, external pressure, local bending, abrasion, current-induced movement and long-term exposure to the marine environment.
A dynamic cable or umbilical may be subjected to repeated combinations of tension, bending, torsion, reeling, reverse bending and movement at hang-off or touchdown locations. These conditions can require a different cross-sectional arrangement, lay geometry, material selection and qualification programme.
Where the cable forms part of the lifting, towing or deployment system, the strength member becomes a fundamental part of the product architecture. Steel-wire armour can provide tensile capacity, mechanical protection and additional submerged weight. Aramid and other high-performance synthetic fibres can provide substantial strength with lower mass and different stiffness, fatigue and termination characteristics.
Fibron develops both steel-armoured and synthetic-fibre-reinforced constructions. The appropriate solution depends on required breaking load, diameter, submerged weight, flexibility, torque behaviour, fatigue duty, handling equipment and the way in which load will be transferred into the terminations.
Composite cable and umbilical applications
Fibron’s bespoke approach allows the construction to be adapted to a wide range of offshore and subsea systems, including:
ROVs and subsea vehicles
Tether cables, tether management system connections, load-bearing main-lift umbilicals and vehicle or tooling connections carrying combinations of power, telemetry, video, fibre-optic data and control signals.
Subsea trenchers, crawlers, tooling and mining equipment
Power and control connections for equipment that may impose high electrical demand, mechanical loads, repeated movement and exposure to abrasive or debris-rich environments.
Towed sonar, survey and defence systems
Load-bearing tow cables and electro-opto-mechanical connections for sonar bodies, sensor arrays, survey equipment and other mission-critical systems.
Deep-ocean research and seismic systems
Cables and umbilicals supporting observation platforms, instrumentation, sensor packages, airgun and source systems, data acquisition and deep-water deployment.
Offshore energy and subsea intervention
Control, tooling and intervention connections, including applications associated with subsea production equipment, BOP systems, IWOCS equipment, hydraulic tooling, flying leads and other offshore operating systems.
Marine renewable energy
Dynamic and static connections for wave and tidal energy devices, floating wind, floating solar and other prototype or commercial energy-capture systems.
Commercial diving and subsea rescue
Umbilicals combining breathing gas, gas reclaim, hot water, communications, video, power, pneumatics and monitoring services.
Other specialist applications
Related applications also include aquaculture, hull cleaning, cable burial, marine robotics and other equipment operating in wet, abrasive or mechanically demanding environments.
Prototype and short-length composite cables
New subsea equipment frequently requires a connection that has not previously existed. The cable architecture may therefore have to be developed alongside the vehicle, tool, sensor, winch, connector system or deployment method.
A prototype or qualification length allows important characteristics to be assessed before a full production commitment. These may include:
- finished diameter and dimensional stability;
- weight in air and water;
- flexibility and bend stiffness;
- electrical and optical performance;
- hose pressure and flow performance;
- reeling and sheave behaviour;
- interaction with the winch or tether management system;
- termination and connector integration;
- handling by the vehicle or operating team.
Fibron’s manufacturing capability is particularly suited to prototypes, one-off assemblies, demonstrator systems, qualification lengths and short production runs. Designs can be refined following testing or equipment trials before progressing to longer or repeat manufacture.
Testing and qualification
The testing programme should reflect the product’s operating duty and the principal technical risks identified during design. Depending on the construction and application, testing may include:
- dimensional and visual inspection;
- conductor resistance, continuity and insulation-resistance testing;
- electrical withstand testing;
- partial-discharge or breakdown testing for relevant high-voltage designs;
- optical continuity and attenuation measurement;
- hose proof-pressure, leak and functional testing;
- tensile, break-load and termination-load testing;
- reeling and unreeling trials;
- bend-over-sheave and cyclic bend testing;
- torque and rotational-behaviour assessment;
- crush and clamp testing;
- bend-stiffness measurement;
- functional testing of the completed terminated assembly;
- factory acceptance testing and inspection.
Where a contract calls up API 17E, ISO 13628-5 or another industry standard, the applicable edition, test scope and acceptance criteria should be agreed at the start of the programme. Fibron can also work to customer-specific qualification regimes and coordinate independent or third-party testing where required.
Documentation can include inspection and test plans, qualification procedures, test reports, factory acceptance documentation and the project-specific manufacturing record book.
Complete terminated cable and umbilical systems
Subsea reliability depends on the whole assembly—not only the cable body. Tensile loads must be transferred correctly, electrical and optical interfaces must be protected, hose connections must remain secure and the transition from a flexible cable into a rigid termination must be controlled.
Fibron can coordinate the cable or umbilical with associated components such as:
- mechanical end terminations and armour terminations;
- electrical and fibre-optic connectors;
- moulded or assembled breakouts;
- hose end fittings and hydraulic couplers;
- bend stiffeners and bend restrictors;
- pulling heads, hang-offs and cable grips;
- buoyancy and ballast components;
- junction boxes, termination units and mounting frames;
- reels and project-specific handling equipment.
Treating these components as parts of one engineered connection reduces interface risk and helps ensure that the completed system is compatible with the equipment, deployment method and maintenance strategy.
Why choose Fibron for a bespoke composite cable?
Fibron has specialised in the design and manufacture of subsea and harsh-environment cables and umbilicals since 1986. Its UK manufacturing operation brings together cable and umbilical design, prototype manufacture, production, termination and testing.
Customers can engage Fibron for:
- a completely new composite cable or umbilical design;
- development of an existing outline specification;
- prototype, one-off or short-length manufacture;
- static, dynamic, armoured or load-bearing constructions;
- integration of electrical cables, fibre optics, strength members and hoses;
- project-specific qualification and factory acceptance testing;
- complete terminations, connectors, hose interfaces and ancillary equipment;
- controlled manufacture of repeat or longer production lengths.
Fibron operates an ISO 9001:2015 quality management system covering the design and manufacture of subsea and harsh-environment cables and umbilicals, including terminations and associated technical support.
The objective is not simply to manufacture a cable to a drawing. It is to engineer a reliable connection around the customer’s electrical, optical, fluid-transfer, mechanical, installation and operating requirements.
Frequently asked questions
What is the difference between a composite cable and a hybrid cable?
The terms frequently overlap. Both generally describe a cable containing more than one type of functional element—for example, electrical conductors and optical fibres. Composite cable is the broader term, while hybrid cable is often used specifically for combined electrical and fibre-optic constructions. Products that also carry tensile load may be described as electro-mechanical or electro-opto-mechanical cables.
Can a subsea umbilical contain both cables and hoses?
Yes. A multi-service umbilical can combine electrical power, control circuits, data components and optical fibres with hoses for hydraulic fluid, air, gas, water, hot water or compatible chemicals. The cable, hose, strength and termination elements must be engineered as one system because they behave differently under tension, bending and external pressure.
Can a composite subsea cable be load-bearing?
Yes. Steel-wire armour, aramid yarns or other high-performance strength members can be incorporated when the cable must withstand deployment, towing, lifting or suspended loads. The appropriate construction depends on working load, minimum breaking load, submerged weight, stiffness, fatigue duty, torque behaviour and termination arrangement.
What is the difference between a static and dynamic subsea cable?
A static cable remains largely stationary after installation. A dynamic cable is repeatedly moved, reeled, bent or loaded during operation. Dynamic service generally requires closer consideration of lay geometry, cyclic strain, bend stiffness, torsion, fatigue, handling equipment and the behaviour of the cable at terminations, sheaves and hang-off points.
Can Fibron manufacture prototype or short-length composite cables?
Yes. Fibron’s flexible manufacturing operation is suited to prototypes, one-off products, trial lengths and short production runs as well as longer manufacture. A prototype can be used to verify cable diameter, flexibility, electrical performance, hose functionality, handling behaviour and termination integration before the final production design is confirmed.
Discuss Your Composite Cable Requirement
If you are developing a subsea or offshore system and need a bespoke composite cable or umbilical, please get in touch with Fibron. Our engineers can support the complete development process from initial feasibility and cable architecture through prototype manufacture, qualification, termination, testing and production supply.
