Applications
Tether cables are used in conjunction with ROV vehicles being deployed from TMS/cage systems or directly from the surface for the smaller ROV´s.
Tether design and manufacture is optimised with respect to providing tethers with high flexibility, good durability, natural buoyancy and minimum drag.
When going deeper, a compact and reliable cable core gets increasingly important. Positive buoyancy may be required even at 3000m water depth, a property which incompressibility is key to achieving as relative weight increases as the cable's volume decreases.
Design
- Power Supply, ROV motor: three large Copper Conductors rated to 3.3kV. Capable of supplying power to a 100HP motor.
- Signal: a selection of max 12 SM/MM optical fibres protected by a laserwelded steel tube. A central quad for backup.
- Power Supply, Instrumentation: small Copper Conductors supplying power to the ROV instrumentation
- Earth Conductors: copper Conductors with semiconductive insulation, used to detect fault currents and drain any charges building up in the cable.
- Shield: copper Laminate increases the effect of Earth Conductors.
- Inner Sheath: a layer of thermoplastic elastomer is applied to the core. Protects the cable core and enables easy termination.
- Armouring: two layers of high-strength aramid yarns provide light-weight tensile strength and torque balance.
- Solid Fillers: a few solid polyethylene fillers are inserted for increased attachment between aramid yarns and outer jacket.
- Outer Sheath: an outer layer of thermoplastic elastomer acts as a mechanical protection in addition to preserving the aramid yarns.
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