Passive heave compensation

Passive heave compensation is a technique used to reduce the influence of waves upon lifting and drilling operations.

The main principle in PHC is to store the energy from the external forces (waves) influencing the system and dissipate them or reapply them later.

A typical PHC device consists of a hydraulic cylinder and a gas accumulator.

Not requiring external energy, PHC may be designed as a fail-safe system reducing the wave impact on sub-sea operations.

as the systems natural frequency, defined as: This leads to the following expression for the ratio: The transmissibility