Exploring Subsea Force Measurement Applications

Accurate force measurement is compelling for subsea environments. It is essential for monitoring the integrity of structures such as platforms, moorings, and subsea pipelines. It also plays a central part in managing operations such as towing, hoisting, and winch tensioning. Without quality data, operators are operating blindly, risking costly equipment damage, environmental harm, and potential loss of life.

What is “Subsea”? The term “subsea” refers to technology, equipment, and operations that are fully submerged in the ocean, typically at a significant distance from the shore and often on the seabed in deep waters. While frequently associated with the energy sector, subsea technology is crucial across a variety of maritime applications, including aquafarming, oceanographic research, telecommunications, and deep-sea exploration.

Types of Sensor-Enabled Subsea Equipment and Systems

Subsea environments require a wide range of specialized equipment, each serving a specific purpose. Interface supplies various load cells and instrumentation devices designed for use in this equipment and systems for subsea locations. Most apparatus and equipment require reliable force measurements to ensure safe and efficient operation. This equipment includes:

Remotely Operated Vehicles (ROVs) – Unmanned, tethered underwater robots used for inspection, maintenance, and repair. Load cells are critical for monitoring the tension on the ROV’s umbilical cable to prevent damage. Learn more about Autonomous Underwater Vehicle force measurement solutions here.
Mooring and Anchoring Systems – Used to secure floating structures like ships, platforms, and buoys. Load pins and tension links monitor the forces on these mooring lines, ensuring they can withstand severe weather and strong currents. Read more: Mooring Line Tension Testing.
Subsea Wellheads and Trees – The control systems for underwater oil and gas wells. Sensors monitor pressure and other critical parameters to ensure safe operation. Check out Examining Force Measurement in Subsea Oil and Gas
Winches and Hoisting Equipment – Used to deploy and recover heavy equipment, cables, and ROVs. Load cells ensure that lifting operations do not exceed the safe working load of the equipment, preventing line breaks and equipment loss.
Pipelines and Cables – Force sensors are used during the laying and recovery of pipelines and fiber optic cables to monitor tension and prevent damage.

Interface | Blue Economy Tech: Why Load Cells Matter Underwater and Offshore

Watch this video on YouTube

Exploring Subsea Sensor Technology

Interface designs and manufactures a range of load cells to meet the unique demands of subsea applications. These sensors are designed with specific features to withstand intense pressure, corrosive saltwater, and the potential for explosive atmospheres.

Interface Sealed Load Cells are used for underwater and submersible applications; load cells must be completely sealed to prevent water ingress. Interface utilizes hermetic sealing techniques and corrosion-resistant materials, such as stainless steel, to ensure the long-term reliability of its sensors. This prevents damage to the internal strain gauges, maintaining accuracy even at significant depths. Examples of Interface’s sealed sensors include: 3450 Sealed Column Load Cell With Integral Cable for Hazardous Environments, WMC Sealed Stainless Steel Miniature Load Cell, WMC Sealed Stainless Steel Miniature Load Cell, and SSB Sealed Beam Load Cell.

Interface IP-Rated Sensors use the Ingress Protection (IP) rating system, which classifies the degree of protection provided against dust and water. Subsea applications often require a high IP rating, such as IP68, which signifies that the sensor is protected against continuous submersion in water. Interface’s IP-rated load cells are meticulously engineered to meet or exceed these standards, providing dependable performance in splash zones and underwater.

Interface ATEX Certified Solutions are used in environments where flammable gases or dust may be present, such as in specific oil and gas applications. ATEX (Atmosphères Explosibles) certification is a legal requirement in the European Union. Interface offers ATEX-certified sensors and wireless solutions, including wireless load pins designed for hazardous environments, that prevent sparks and operate safely in these volatile conditions. This ensures compliance with safety regulations and protects against explosions. Explore our Hazardous Locations ATEX 101 overview.

The most common uses of interface sensors in subsea environments include our load pins, load shackles, and tension load links. Our wireless options are popular because of their suitability for different locations. These measurement transducers are compatible with our various wireless sensor transmitters, receivers, and handheld displays, enabling the creation of complete systems. Our Wireless Crosby Bow Load Shackles are designed for mooring line tension testing and rigging inspections. Additionally, our load shackles are compatible with the WTSTL Wireless Tension Link Load Cell. The WTS-BS-4 Wireless Industrial USB Base Station is a widely used transmitter offering excellent coverage. It can be easily paired with our handheld displays, such as the WTS-BS-1-HA Wireless Handheld Display for Multiple Transmitters or the WTS-BS-1-HS Wireless Handheld Display for Single Transmitters.

Interface Complete Systems enables subsea engineers and measurement system designers to use our pre-configured systems. Interface Complete Systems highlights how to build reliable, ready-to-use force measurement solutions by combining precision load cells, multi-axis sensors, load pins, tension links, shackles, and torque transducers with compatible instrumentation, cabling, and connectors with a system calibration. Due to the subsea requirements, these three configurations are most aligned with common use cases for wireless systems.

WTSTL WTS-BS-4 System

WTSSHK-D WTS-BS-4 System

WTS 1200 Data AQ Pack System

Specific Subsea Applications

Mooring System Integrity

Offshore platforms and buoys rely on robust mooring systems to remain in position. Monitoring the tension on these mooring lines is crucial, especially during harsh weather conditions, to prevent catastrophic failure. The sensors must withstand constant exposure to saltwater and immense pressure.

Load pins are integrated directly into the shackles connecting mooring lines to the platform. These sealed, corrosion-resistant load pins provide continuous, real-time data on the tension exerted on each line. This information allows operators to proactively adjust line tension or detect potential issues before a failure occurs. Our wireless hazardous environment load pins are handy here, eliminating the need for complex cabling and allowing for easy data collection.

ROV and Submersible Deployment

Deploying and recovering heavy subsea equipment like ROVs and manned submersibles requires precise control. Overloading the winch cable can cause it to snap, resulting in the loss of millions of dollars in equipment. The force measurement system must be reliable and provide instant feedback.

Tension links are placed in line with the winch cable. As the equipment is lowered or raised, the tension link accurately measures the force on the cable. This real-time data is displayed to the winch operator, who can adjust the speed and power to stay within safe operating limits. Our rugged, high-capacity tension links are built to handle the significant loads and dynamic forces of these operations.

Underwater Cable Laying and Recovery

Laying fiber optic or power cables on the seabed is a delicate operation. The cable must be laid with a consistent tension to prevent damage or kinking. Similarly, when recovering a cable for repair, the operator needs to know the exact force to avoid overstressing it.

A custom tension link or load cell system is engineered and mounted on the cable-laying or recovery vessel’s sheave wheel. This solution provides continuous tension feedback to the control room. Because these operations often have unique requirements—such as non-standard cable sizes or specific environmental conditions, a custom-engineered solution from Interface ensures a perfect fit and reliable performance, safeguarding the integrity of the expensive cable.

Why Interface and Subsea

Interface’s expertise extends beyond standard off-the-shelf products. We collaborate with partners in the maritime and energy sectors to provide tailored solutions for specific subsea needs. Our product offerings include our load cells, load pins, tension load links, instrumentation, wireless systems, and custom solutions.

Load pins are a common choice for subsea applications as they can be easily integrated into existing structures, such as shackles, pulleys, and mooring systems, to measure force. Interface’s load pins are available in wireless and hazardous environment-rated versions. Tension load links are ideal for measuring force in-line with a wire or cable; tension links are essential for monitoring towing loads, mooring lines, and underwater cable tension. They are rugged and designed for high-capacity applications. Interface Systems and Custom Solutions provide you with options for unique projects. Interface can engineer and manufacture modified sensors to meet exact specifications, including specialized dimensions, higher pressure ratings, or custom data transmission methods. Our experience ensures that our products meet the high-intensity needs of any subsea equipment.

From monitoring anchor loads on a fishing vessel to ensuring the structural integrity of a research submersible, Interface provides the force measurement technology that guarantees accuracy, efficiency, and most importantly, safety.

Maritime Industry: Force Measurement Solutions