How to find the right termination solution for your subsea equipment

If you’ve ever worked on a subsea project, you’ve probably seen it happen: Two world-class pieces of technology, flawlessly designed, but they never perform as expected once deployed. Why? Often, the weakest link isn’t software, electronics, or hydraulics. It’s the cable termination. That small interface between the umbilical and the equipment carries everything: power, data, tension, and trust. And when it’s not engineered to the same standard as the rest of the system, the deep sea has a way of reminding you. Fast.

The Hidden Science of Terminations

A cable termination isn’t just a mechanical fixture. It’s a system integration challenge. Where mechanical load paths, sealing physics, and signal integrity all meet in a few centimeters of engineered metal. 
At DeRegt, we design these interfaces every day for ROVs, sonar systems, seismic tools, and renewable energy platforms. Here’s what we’ve learned after decades under pressure.

1. Deck-end vs. Sea-end: two different worlds

On deck, everything’s about handling and power routing. The deck-end termination anchors the cable to a winch and transfers force to a fixed mount. It must be robust, modular, and easy to service. At the sea-end, things get far more interesting. Now you’re fighting hydrostatic pressure, hydrodynamic drag, and constant motion. This is where termination design becomes a science of balance, between stiffness and flexibility, armor and isolation, load and precision.

2. Anatomy of a sea-end termination

There’s no “one-size-fits-all,” but we often work within four broad architectures:

• Faceplate designs, where multiple connectors converge on one sealed interface.
• Inline terminations, sleek and hydrodynamic for seismic and towed arrays.
• Mechanical head terminations, where the armor takes the load and the core delivers the signal.
• Flexible terminations, articulated titanium structures that bend gracefully over winches without stress failures.

Each design tells a story about the mission it serves. Each is a balance of geometry, materials, and physics.

3. The engineering inside the metal

What looks like a single “end fitting” is actually a system of interdependent components:

• Mechanical termination: transfers tons of tension through resin-bonded armor wires or aramid braids.
• Bend protection: distributes stress where rigid meets flexible. The classic fatigue hotspot.
• Sealing: layers of O-rings, glands, and molding keep seawater where it belongs: outside.
• Connectors: hybrid, optical, or electrical. The “brain ports” of the operation.

When these elements work together, your cable doesn’t just function — it thrives. When they don’t, the failure modes are immediate and unforgiving.

4. The human side of engineering

Designing for 6,000 meters of depth means designing for zero tolerance. But it’s not just about technical precision, it’s about collaboration. When we co-develop termination concepts early in a project, we often prevent months of redesign later. Small shifts, like choosing a different connector geometry or adjusting armor lay length, can save enormous costs and downtime. The earlier a cable specialist joins the table, the better the system performs as a whole.

5. Why it matters

Terminations are a perfect metaphor for engineering itself: the part everyone overlooks. Until it fails. But when designed right, they embody everything we admire about good engineering: elegance under stress, precision in chaos, and reliability when it matters most. At DeRegt, we see terminations not as “endpoints,” but as enablers. The point where complex systems truly come alive.