Active heave compensation (AHC) is a technique used on lifting equipment to reduce the influence of waves upon offshore operations.
[2] The performance of an AHC system is normally limited by power, motor speed and torque, by measurement accuracy and delay, or by computing algorithms.
Choice of control method, like using preset values or delayed signals, may affect performance and give large residual motions, especially with unusual waves.
AHC cranes are typically used for sub-sea lifting operations or construction, and special rules applies to certified heave compensating equipment.
These towed systems usually have low water resistance, and Constant Tension (CT) does not help stabilize the equipment when the vessel is affected by waves.
Cost and complexity of AHC systems have limited the use of this technology in other subsea applications, such as marine research.
Control technology advancements in recent years are allowing AHC to become more standardized and available for applications where cost and simplicity are significant.