Subsea cables and umbilicals are used for a variety of purposes in the offshore industry, primarily for the transmission of information, power, and fluids over long distances in harsh environments, where surface infrastructure is not feasible. They also provide a reliable and cost-effective means of transmitting information and power between remote locations. Some common applications include

1. Telecommunications: Subsea cables are used to transmit internet, phone, and other telecommunications data across oceans and between continents.
2. Oil and Gas: Umbilicals are used to provide hydraulic power, electrical power, and communication to subsea oil and gas production equipment such as wells, manifolds, and subsea control modules.
3. Renewable Energy: Subsea cables are used in offshore wind farms to connect the individual turbines to a central substation onshore.
4. Scientific Research: Subsea cables are also used in scientific research to transmit data from oceanographic instruments, such as deep-sea cameras, seismometers, and sonars.
5. Military and Defence: Subsea cables are used for military and defence purposes to provide secure communication and surveillance capabilities.

The critical design features of a these structures include:

1. Strength and Durability: Subsea cables must be designed to withstand the harsh and corrosive underwater environment. They must be able to withstand the pressure, temperature, and salinity of seawater as well as mechanical stresses caused by currents, waves, and tidal forces.
2. Insulation: The insulation of a subsea cable is critical for maintaining the electrical performance of the cable. The insulation must be able to withstand high voltages, prevent water penetration and provide resistance to damage caused by environmental factors.
3. Water-blocking: Subsea cables must be designed to prevent water ingress, which can cause short-circuits and degradation of the cable insulation. Special water-blocking compounds are used to prevent water from entering the cable.
4. Armoring: To protect the cable from mechanical damage and external impact, armoring is used. The armoring can be in the form of steel wire or other composite materials.
5. Conductors: Subsea cables must have sufficient conductors to carry the required electrical power and signals. The size, number, and configuration of conductors will depend on the specific application.
6. Connector Design: Connectors used to connect subsea cables must be designed to withstand high pressure and be reliable in harsh environments. The connector design must be able to accommodate variations in cable diameter and provide effective sealing to prevent water ingress.
7. Monitoring and Maintenance: Subsea cables must be designed to enable monitoring and maintenance. Sensors can be incorporated into the cable design to monitor the condition of the cable and detect any faults or damage. Additionally, the cable must be designed to allow for easy repair or replacement in case of failure or damage.

Overall, the critical design features of subsea cables are essential for ensuring their long-term performance and reliability in harsh and challenging underwater environments.

Continuum Blue has provided numerous localised stress-strain analysis work for clients like JDR Cables to ensure that their design requirements are meet.