In naval and subsea defense systems, a cable’s strength member isn’t just another component — it’s the backbone of the entire design. The choice you make here determines how well the cable handles tension, dynamic loads, deployment cycles, and the harsh mechanical forces of the open sea. Getting this wrong can compromise performance. Getting it right keeps missions operational, predictable, and safe.
Every sonar, towed system, or naval asset comes with its own operational profile. That’s why selecting the strength member requires a clear understanding of the mechanical demands, environmental conditions, and fatigue behaviour your cable will face. Below, we break down the two primary options and when each type makes sense for mission-critical subsea systems.
The most vulnerable components of a sonar cable are laid up in the core of the cable. This is done for component protection. Around the core components, the strength member is wrapped.
In addition to higher mechanical resistance and improved load-handling characteristics, this strength member has another important function: taking over the entire load from the aforementioned fragile components. The sonar cable is designed in a way that the strength member fails first, sparing the opto-electric components in the core in case of a defect.
When choosing a strength member, there are mainly two options: steel armor and aramid. Both types have their own advantages and challenges, making it easy to make the choice based on the cable's specifications.
For example, steel armoring is best known for its crush resistance. It is particularly chosen when there is a high probability that the cable will be subjected to a lot of pressure and weight radially to the cable.
On the other hand, aramids are a lot lighter, which makes them ideally suited for neutrally buoyant cables. Especially in Naval Defense aramids are used a lot, since Towed Array Sonar Systems are often neutrally buoyant.
In short, the difference between steel armoring and aramids is mainly the design criteria: is crush resistance and endurance more important, or is the weight in seawater of the cable as light as possible? The price of materials is not a selection criterium for the strength member of a naval cable.
The strength member is an important part of your naval sonar cable, just like every other component. In the end, all components must work together properly. Therefore, all of these components must be extensively tested and validated.
That is why our sonar cable experts created an E-book on Testing and Validating. Download the E-book here and find out how to ensure that your strength member and all other components are properly validated:
With all other questions about your cabling needs, you can contact my colleagues or me here. Our cable experts are always happy to help, advise or guide you in all your cable requirements.