Active Heave Compensation Systems
Motive can supply Active Heave Compensation with any equipment designed to lift and deploy loads subsea, covering applications such as cable lay, retrieval and maintenance, oil and gas, or decommissioning operations deploying and retrieving subsea equipment, or the installation of pipelines and other subsea structures.
Incorporating an Active Heave Compensation Lifting System allows counteraction of the vertical motion of a vessel caused by waves and sea swell. Using sensors to monitor and process vessel motion data, a winch drum’s position can be dynamically adjusted ensuring it maintains a steady load position, enabling precise handling of subsea equipment during rougher sea conditions.
First design-build AHC Winch delivered in 2020
Motive delivered its first design-build Active Heave Compensation (AHC) winch package for a key client back in 2020. The client requested the winch for use during trenching vehicle operations on a high-profile offshore wind project and wanted to be able to minimise weather-related downtime.
Motive supplied a 100Te SWL Hydraulic Drum winch package, complete with Scantrol AHC System (based on their mTrack controller); along with Deck Grillage, and a 680kW Hydraulic Power Unit.
Today, Active Heave Compensation (AHC) Winch Packages are available from Motive bases across the UK, in Stavanger, Norway, and on a global basis.
What is Active Heave Compensation?
Scantrol mTrack AHC controller
The mTrack AHC controller with integrated Motion Reference Unit (MRU) measures vessel heave, pitch, and roll motion with high accuracy, and controls the winch drum to compensate for the vessel motion. Even in moderate sea conditions waves can make operations challenging with significant heave motion, so by introducing the ability to eliminate this vessel motion from transferring to the load, the operator has precise control. This allows a stable load position to be maintained, delivering a steady lift or descent to ensure equipment reaches its target location safely, even in rough sea conditions.
With a built-in ´toolbox, the mTrack includes AHC Analyser, auto tuning, Dynatest, remote support, AHC logger and AHC predictor. The AHC Predictor and Analyser tools help Operators determine how much of the winch capacity is being used at any given time and when to go into AHC operation, with real-time compensation delivered through continuous adjustments to counter the displacement from vessel heave.
Enhanced Safety
"A key benefit of Active Heave Compensation is it allows Operators to concentrate on other activities, without having to constantly monitor and react to weather conditions."
The Safety Advantages of Active Heave Control
Amongst the many advantages for offshore operations, Active Heave Compensation reduces the risk to high-value assets, while increasing operational times by minimising weather standby.
Operators gain peace of mind, knowing the AHC system automatically compensates for weather changes, allowing them to focus on core tasks. The logging functionality can also be helpful for hydraulics or mechanical fault finding.
Safety features include emergency stop, load limit indicators, and fail-safe functions.
Transforming operations with easy-to-use Active Heave Compensation
Motive has enjoyed a longstanding working relationship with Scantrol, leading authority in monitoring and control systems for the marine and offshore industries. Utilising Scantrol’s proven technology across all our AHC systems, Motive installs, commissions, and tests the software using Dynatest with simulated vessel motion and speed test functionality. This ensures minimal set-up requirements once equipment reaches the back deck, with no need for live testing in rough conditions. All systems come complete with remote support functionality for added confidence.
For the 100Te winch build, Dynatest was used to replicate the Motion Reference Unit (MRU) signal for vessel motion and recorded the winch responses enabling all testing to be completed for our client onshore at the Motive base.
The user interface shows how the vessel and load are moving in the same way, and once the operator turns on AHC the graphs reflect how the vessel motion is being filtered away from the load.
Regardless of the load being handled, sensors transmit a signal showing how the winch is moving, and the auto-tuning feature adapts accordingly.
Multiple assets can be controlled using the same AHC system via an interface system such as a Winch Programmable Logic Controller (PLC).
Technology advances opens doors for wider use of Active Heave Compensation
Motive can supply Active Heave Compensation with any equipment designed to lift and deploy loads subsea, covering applications such as cable lay, retrieval and maintenance, oil and gas or decommissioning operations deploying and retrieving subsea equipment, or the installation of pipelines and other subsea structures.
Advances in AHC technology mean this is now a viable option for a wider audience to reap its benefits. With more affordable, less complex options available, it has opened the possibilities both for the Rentals market as well as considering its use for other assets onboard such as smaller Cranes or Launch and Recovery System (LARS).
By maintaining a stable load position, the AHC winch enhances the safety and efficiency of subsea operations, making it a valuable tool in the offshore industry. Critical for subsea installations, AHC reduces the risks to equipment and personnel, minimises stress on cables and other assets, and helps mitigate weather downtime by allowing operations to continue in rougher conditions.
Reach out to discover more about adding Active Heave Compensation for your next project.
