Cranemaster Active Heave Compensator

Cranemaster’s active heave compensator (AHC) offers the best of two worlds, combining well proven passive heave compensation technology for balancing the load, with additional active tension regulation, precise motion control and state-of-the art power management. The result is a hook mounted, energy efficient and self-sustained and fail-safe system, for enabling AHC functionality on demand.

What is Heave Compensation?

Heave compensation is a technology used in offshore and marine applications to mitigate the effects of vertical motion, known as heave, experienced by floating structures such as ships, floating platforms, or vessels. Heave refers to the upward and downward movement of a structure caused by waves, currents, or other environmental factors.

Passive and active heave compensators are designed to counteract or minimize the vertical motion of a floating structure. This is particularly important in offshore industries such as oil and gas and off-shore wind, where precise positioning and stability are crucial for various operations like drilling, lifting heavy loads, or conducting subsea operations. As a result, heave compensators minimizes weather-related downtime, increases operational time and decreases damage to your equipment.

What is the difference between Passive and Active Heave Compensation?

Passive Heave Compensation (PHC) relies on mechanical or hydraulic systems that absorb and dampen the effects of heave motion.

Active Heave Compensation (AHC) use sensors to detect the movement of the platform and then employ actuators (hydraulic or electric) to actively adjust the position of components, such as cranes or tools, to maintain stability and reduce heave-induced motions.

How does the Cranemaster Active Heave Compensator work?

The Cranemaster Active Heave Compensator offers the best of two worlds, combining well proven passive heave compensation technology for balancing the load, with additional active tension regulation, precise motion control and state-of-the art power management.

The Passive Heave Compensator-technology ensures that the load is initially balanced, which effectively reduces the required energy for the active compensation. This also provides an intrinsic fail-safe state for the system, by reverting to passive compensation in an instant. The Active Heave Compensator then senses and predicts the motions to be compensated and applies stored energy to actively induce the required compensating motion.

In addition to the active heave compensation, the Cranemaster AHC offers the ability to control the tension level, enabling gradual tensioning and load transfer during lift-off and landing.

Paired with the already well proven Cranemaster Quick Lift functionality, this provides an optimal solution for demanding transfer lifts, where reduction of dynamic loads and avoidance of re-entry is equally important.

Benefits of Heave Compensation

Both active and passive heave compensation can be utilized in all scenarios where there are relative heave motions between the crane hook and the foundation being lifted to or from. The load is kept in position regardless of vessel motion, and makes it possible to position loads accurately, even in rough weather. This maximizes the weather window, increases operational time and decreases damage to your equipment.

​Typical Applications and benefits

• Feeder of WTG components
  In order to speed up ​the installation of offshore wind farms, feeder barges or vessels transports components to the installation vessel. During the lift off from the feeder barge, DAF values can exceed the allowable levels either on the crane or the components. A Cranemaster in-line active heave compensation (AHC) unit, improves the DAF values significantly providing a safer lift.
  
• Backloading​ / vessel to vessel transfer
  When transferring goods between vessels, the landing impact can cause excessive shock loads to the object to be lifted. A Cranemaster in-line active heave unit reduces such shock loads.
  
• TP installation ​from floating vessel
  By using a Cranemaster in-line active Heave unit, the landing impact the Transition Piece of a wind turbine generator foundation is much softer.
  
• Light Subsea structures (Xmas trees, spools, etc.)
  Due to the limited drag area of certain subsea structures, an in-line Active Heave Cranemaster ensures a low landing speed on the seabed.​​
  
• Cranes at quay side where vessel heave is an issue
  In order to handle heave or tide motions ​at the quay side, a Cranemaster active heave unit compensates for these motions.
  
• Offshore Maintenance
  Doing repair from a floating vessel incorporates motions. A Cranemaster contributes to reduce such motions making repair offshore possible and avoid expensive transportation to shore.

​Key Features

• Powerful
  Reduces of heave motions and velocities by up to 95%.
  
• Versatile
  Hook-mounted, plug and play, compact and compatible with vessel’s existing lifting equipment.
  
• Economical
  Reduction of your TCO: low investment costs through a renting option compared to other alternatives. Better utilization of vessels without AHC. Less tear on wire compared to cranes with AHC. Rent for short or long period.

• Energy efficient
  Low power consumption because of contribution from PHC technology.​
  
• Fail safe
  In case of a power failure, the system can continue to operate with PHC functionality.​
  
• Reliable
  Cranemaster offers a well proven technology. Strong in-house lifting engineering expertise through more than 40 years of operation.