ROV Cable Construction

Each subsea project is different and the same is true for the corresponding (ROV) cable construction. After all, ROV systems are used for a broad range of purposes. Which type of ROV cable is best for your subsea project?

To answer this question, it is important to know how an ROV cable is built. Which elements determine the geometry of a cable? And which cable specifications are important for your ROV system?

Our experts produce cables for a variety of ROV systems. As each purpose requires a different cable construction, there is no such thing as a catalog; your requirements are translated into fit-for-purpose designs.

On this page, we explain why each ROV cable is custom constructed.

Cable Construction

In the example below – an ROV cable – components are laid up in helices with extruded plastic sheets and tapes separating the layers. The electrical and optical components are laid up in the core. Around the core, a strength member is wrapped. In this case a steel armor with 2 layers.

Another common material used as a strength member in ROV cables is aramid fiber, which is much lighter.

Conducting electricity and data

Electrical conductors are usually made of copper with thermoplastic insulation. Data is usually sent via optical fibers these days. Fragile components like optical fibers are placed towards the center for crush resistance. The helical structure makes it possible to bend and stretch the cable construction without permanently deforming or breaking the components.

Rotation

In our work to make the best ROV cables, we focus a lot on ‘torsion balance.’ This means we designed the cables to stay steady and not twist when under tension. To do this, we carefully adjust the cable layers’ angles and ensure each layer is balanced just right. This step is vital to ensure the cables work their best and last long, especially in harsh underwater conditions.

If you want to learn more about how we do this and why it’s crucial for underwater projects, check out our on-demand webinar. It’s led by Sander van Leeuwen, our R&D Manager at DeRegt. In this webinar, you’ll learn a lot about ROV cable design. We’ll cover everything from how the cables are used, how deep they go, how to reduce downtime, and how to balance power needs, cable life, and your budget.

Which cable do I need for my application?

Now you know how ROV cable construction works, it is important to know what determines the design for your own subsea project. Which cables are there for ROV systems and what type of cable fits which subsea project?

For example, what type of power should your cable be able to transfer? And how deep does your ROV operate? The latter has a large impact on the material used for your strength member, as steel is often too heavy for deep-water operations. In such cases, aramid fibers or other lightweight synthetic fibers might be the best option.

The fact that ROVs are operating at greater depths is a trend that we see a lot, but selecting an extra-long cable “just to be safe” is a common mistake. This means that large pieces of cable remain on deck when not using its full length. If a lot of cable is left on the reel and the system runs on full power, the cable can get too hot.

This example shows how important fit-for-purpose is. Not only length is very important; weight and conductivity also play a major role. Think carefully about the application of your ROV cable and what specifications fit this purpose!

How does my ROV system impact the design of the cable?

As mentioned, each subsea project is different, and this uniqueness is reflected in the corresponding ROV cable construction. Since ROV systems serve a broad range of purposes, from deep-sea exploration to pipeline inspections, these specific applications significantly influence the design of the cable. The cable must be tailored to handle each task’s unique stresses, depths, and operational demands. Conversely, the cable’s capabilities and limitations impact the ROV system’s overall performance and efficiency.

Understanding this interplay between your ROV system and its cable is crucial for optimal performance. The following page delves deeper into how different ROV applications dictate cable design, covering aspects like strength, flexibility and durability. We also explore how the right cable design can enhance the capabilities of your ROV, reduce operational risks, and improve efficiency.