Passive heave compensation


What is Passive Heave Compensation (PHC)?

A heave compensation system in which there is a fixed physicical reference point is called a Passive Heave Compensator. In most cases the seabed or an oil rig serves as the physical reference point of this type of heave compensation system.

What is the difference between PHC and AHC?

Passive Heave Compensators use a fixed reference point where Active Heave Compensators use a Motion Reference Unit. Next to that, another major difference between Passive Heave Compensators and Active Heave Compensators lies in power consumption. PHC does not consume external power while AHC requires an external power source.

When to use Passive Heave Compensation?

The PHC is the best solution when having a fixed reference point. Typical areas of application are subsea operations where the load is situated on the seabed, the drill string compensators in riser systems and dredgers. When not having a fixed reference point a Motion Reference Unit( (MRU) replace the fixed referenc point and therefore an Active Heave compensator is used.