Basic Passive Heave Compensator
RIGEL is a basic passive heave compensator for predictable splash-zone crossings and standard subsea lifts. It is the go-to choice when the operation needs reliable dynamic-load reduction without adaptive or active control.
Rugged simplicity
RIGEL is a single-cylinder passive heave compensator unit, with a simple and reliable design, that has competitive advantages:
- Light weight
- Low cost
- Comparatively low stiffness
- Externally adjustable bi-directional damping
- Fast gas filling
- Overpressure protection
- Bi-directional end damping
The numbers, first
| Maximum force (SWL) | 55–1,000 tStandard steps: 55 · 75 · 125 · 150 · 250 · 300 · 400 · 500 · 600 · 700 · 800 · 900 · 1,000 t |
|---|---|
| Mass in air / in water | 5.8 t / 3.8 t250 t / 3.0 m reference build |
| Stroke length | 1.0–6.0 mStandard steps: 1.0 · 1.5 · 2.0 · 2.5 · 3.0 · 3.5 · 4.0 · 4.3 · 4.5 · 5.0 · 5.5 · 6.0 m |
| Depth rating | 3,000 m |
| Architecture | Single cylinder · gas accumulator · no electronics offshore |
| Damping | Manual · bi-directional · externally adjustable, set on deck |
| Protection | Relief valve (overpressure) · adjustable return damping · bi-directional end damping |
| Sealing | Double seals against water ingress |
| Hydraulic fluid | Compatible with biodegradable fluids |
| Certification | Designed & classed to DNV-ST-0378 · DNV Type Approval in progress |
| Delivery scope | Shackles · lifting points · support feet · filling kit · calculation sheet |
| Budget price | Configurations from approximately USD 35,000 |
| Documentation | GA drawing · datasheet · calculation sheet · OrcaFlex model — on request via the form below |
What RIGEL does to a splash-zone crossing
A 35 t GRP protective-cover case authored at Hs 1.75 m / Tp 7.5 s and executed at modelled Hs 1.8 m after one-decimal rounding, comparing a RIGEL 75 t / 4.5 m in the string against a fixed connection in CONSTELLATION, our in-house time-domain lift simulator. Every figure below is the worst value of its own metric across eight wave realisations, not a single favourable one.
Screening outcome: the four response screens (peak line load, DAF, snap ratio and zero slack) pass in all eight realisations. The separate ND governing-stroke margin requires review: retract-end utilisation reaches 98.4%, and four of eight realisations exceed the < 90% margin, although no sampled end-stop contact is detected.
Engineering prediction for this example case and metocean, not a certified analysis. DNV-RP-N103 informs the modelling method; the numerical screens above are ND references for this study, and project-specific acceptance criteria govern. The operating window is confirmed against project data and the contracted vessel before issue.
See RIGEL in action
A GRP protection cover through the splash zone
In this CONSTELLATION simulation, a RIGEL passive heave compensator takes a GRP protection cover through the splash zone — absorbing the vessel’s heave so line tension stays steady and the load crosses the water surface under control.
Three things, done simply
A gas spring carries the load
RIGEL combines a hydraulic cylinder with a gas accumulator. The gas accumulator provides the spring effect, so the payload stops following the vessel’s heave.
Damping set on deck
Oil flow between cylinder and accumulator is precisely controlled for damping — externally adjustable in both directions, set manually to the operation before the lift.
Protected at the ends
A relief valve prevents overpressure, adjustable return damping ensures safe retraction speeds, and bi-directional end damping protects the compensator from excessive shocks.
All-in-one package
Cylinder, valves and accumulator integrated into one compact package that is well suited for rough offshore usage. Comes with shackles, lifting points and supportive feet.
Committed to safety
We follow and exceed the testing requirements in DNV-RP-N202. All Norwegian Dynamics subsea compensators have double seals to protect against water ingress.
Sustainability
RIGEL is compatible with biodegradable hydraulic fluids for environmentally sensitive operations. It is designed for a long service life with minimal maintenance, reducing waste and environmental impact.
Engineered for the field
Every detail of RIGEL is shaped by real-world offshore operations. Common failure points are eliminated, and maintenance is simplified for harsh environments.
RIGEL’s lane in the Knowledge Hub
Splash-zone crossing
Why the splash is the worst moment of the lift — and how a passive unit carries it.
Read → KB · SYSTEMSPassive heave compensation
The physics of the gas spring: stiffness, damping and where passive is the right answer.
Read → KB · OPERATIONSSubsea lifts
Deck to seabed: hydrodynamic forces, resonance and landing speed on a real lift.
Read →Where RIGEL sits
SWL 55–1,000 tstroke 1.0–6.0 mYou are here 02
SWL 12.5–10,000 tstroke 1.0–6.0 m 03
SWL 30–4,000 tstroke 2.5–8.0 m 07
Lift screeningDNV-RP-N103 Compare all systems →
RIGEL, answered
What applications can RIGEL Basic PHC be used for?
How does RIGEL Basic PHC work?
What are the technical benefits of RIGEL Basic PHC versus competing PHC units?
- Reduced leakage risk
- Easier and much faster filling of gas and oil
- Easier air bleeding
- Lower stiffness and lower weight
- Externally adjustable extension and return damping
- Lifting points for easier handling and support feet to avoid rolling
- Better filling kit and an easier-to-use calculation sheet
Send your lift case.
Lead time and project pricing depend on capacity, stroke and classification — fill in the form and we’ll send drawings, datasheet and a project-specific quotation.
- GA drawing — sized to your duty
- Datasheet & calculation sheet
- OrcaFlex model of the unit
- CONSTELLATION screening across your sea states