Deck→seabed
One continuous coupled run
Products / CONSTELLATION · Lift screening
The weather window your lift can actually work in.
CONSTELLATION — our in-house time-domain lift simulator — models your whole operation deck to seabed, then screens it across every sea state to DNV-RP-N103. You get your operating window (Hs×Tp), the governing limit, and what the compensator buys — before anyone mobilises.
Screened to DNV-RP-N103 · ND-DS basis
Modelled, not certified
Modelled, not certified
First-principles, coupled
CONSTELLATION solves the whole operation from first principles — the payload equation of motion with real-gas gas-spring thermodynamics, Morison hydrodynamics, and the splash-zone and landing dynamic-amplification basis per DNV-RP-N103, on our ND-DS modelling basis. It builds the complete load path — crane, vessel, rigging, compensator and payload — as one coupled time-domain model.
- The complete load path solved as one model — not a static factor
- Hs×Tp swept gate by gate — a window, not a single number
- The governing limit named — and by how much margin
- Fast pre-engineering view — confirmed against your project basis before issue
Modelled, not certified · DNV-RP-N103 / ND-DS
Hs × Tp
Every sea state screened
5
Acceptance gates per cell
RP-N103
DNV screening basis + ND-DS
Modelled in CONSTELLATION · representative example
The operating window, screened
Every sea state, gate by gate. The example below is a representative deck-to-seabed install of a ~190 t subsea structure on the ANTARES 250 t adaptive compensator at head sea.
Splash DAF ≤ 2.0
Slack-sling = 0
Landing DAF ≤ 2.5
Touch-down ≤ 0.5 m/s
Stroke ≤ 90%
Operability — sea state Hs × Tpworkable region vs cut-off
The cut-off line is the workable Hs boundary — it passes Hs 2.5 m at the design period (Tp 8 s). The ringed design cell is the modelled sea state (Hs 2.0 m).
Hs 2.5 m
Operate up to — at the design period, head sea. The compensator keeps the rigging in tension through the splash and softens the seabed set-down.
~85%
Of the season workable on this representative climatology.
0.53×
Splash snap load vs the DNV gate — rigging stays in tension.
Workable Hs cut-off vs Tp
Long-period governed: the window is widest in short, steep seas and narrows toward the swell.
| Standard | DNV-RP-N103 · ND-DS-10 |
| Payload | ~190 t subsea structure |
| Compensator | ANTARES 250 t adaptive |
| Heading | Head sea |
| Climatology | Representative winter |
| Governing limit | Splash-zone gates in steep seas; stroke toward the swell |
CONSTELLATION results are engineering predictions screened to DNV-RP-N103 and our ND-DS basis on the supplied metocean — not a certified analysis. The operating window is confirmed against project metocean and the contracted vessel before issue.
What we simulate
One continuous run, deck to seabed
One continuous run from deck to seabed — not a static check. The compensator switches gas mode per phase as the load goes overboard and submerges.
1 · ON DECKRigged and lifted off; the compensator is locked out.
2 · SPLASH ZONEOverboard through the wave zone — slam and snap load checked.
3 · LOWERINGMid-water descent through the heave-resonance band; drag and added mass build.
4 · SEABED LANDINGSoft set-down onto the soil reaction.
Acceptance criteria
The gates we check
Each screened sea state must clear every acceptance gate to count as workable.
| Splash-zone crossing DAF | ≤ 2.0DNV-RP-N103 |
| Slack-sling events | = 0DNV-RP-N103 |
| Landing DAF | ≤ 2.5ND-DS-10 |
| Touch-down speed | ≤ 0.5 m/sND-DS-10 |
| Stroke utilisation | ≤ 90 %ND-DS-10 |
Acceptance limits shown are CONSTELLATION screening defaults aligned to DNV-RP-N103 practice and our ND-DS basis — not a project-specific certified limit. For execution we screen against the project’s own DNV basis.
2.5 m
Workable Hs at the design period — the window the screen clears.
0.11 m/s
Modelled seabed touch-down speed, well inside the 0.5 m/s gate.
In tension
Sling stays loaded through the splash — the compensator absorbs the wave force into stroke.
Simulation output · every case run with and without
Run both ways — with, without, and the limit
A screening is a counterfactual, not a clip: the same operation is solved with the compensator and without it, against the governing limit. These are the numbers behind the films further down — every value is the simulation’s own result for the stated case.
CYGNUS · STORM TETHERING
Peak tendon tension — same storm, both ways
Snap events 43 → 0Stroke 7.30 of 8 m — stops never touched
TLP tendon pretension · one storm realisation, Hs 4.0 m / Tp 12 s · every peak within SWL
POLARIS · PILE RUN
Hook load — a 1,500 t pile-and-hammer run at 5.0 m/s
Force below held on an 18 MN plateauArrested in 5.0 of 6.0 m stroke
Punch-through arrested inside the stroke · rigid-snap figure is an estimate on crane + sling stiffness
CYGNUS · ANCHOR RECOVERY
Peak line load — suction caisson out of firm clay
Payload ride 3.7× smoother — RMS 0.21 vs 0.80Release rate 0.31 m/s — within the 0.75 m/s limit
Ø6 m caisson, 120 m water · one design sea state, Hs 2.5 m / Tp 8 s · recovered to topside
ANTARES · QUICK LIFT
Minimum deck clearance — lifting off a heaving barge
Re-contact events 0DAF 1.17Stroke 87%
250 t module off a feeder barge, jack-up crane · same sea, Hs 3.5 m / Tp 7.5 s
ANTARES · DECK TO SEABED
Every gate, with margin — one continuous run
Snap-load ratio 0.08Criterion met
150 t subsea manifold to 150 m · Hs 3.0 m / Tp 8.0 s · the film runs this case end to end
RIGEL · SPLASH-ZONE CROSSING
Slack-sling check — DNV-RP-N103 §4.4.3.3
Payload DAF 1.10 (ref. static)Sling-group tension held 146–377 kN
GRP cover through the wave zone · the criterion the splash gate enforces on every screened cell
Representative cases modelled in CONSTELLATION and screened to DNV-RP-N103 practice and the ND-DS basis — engineering predictions, not certified analyses. The POLARIS rigid-snap and CYGNUS bare-wire figures are counterfactual baselines for the same realisation.
Application videos · the full series
See CONSTELLATION at work
Each clip is a CONSTELLATION simulation of a real lift case — the same first-principles, coupled model we run to screen your operation. Watch the compensator hold line tension through the sea state.
RIGEL — splash-zone crossing
Passive heave compensation for a GRP cover lift.
ANTARES — deck to seabed
Adaptive passive heave compensation on a subsea lift.
POLARIS — pile-run protection
Shock absorption for offshore pile driving.
ANTARES — quick lift
Lifting off a heaving feeder barge — clear first time.
CYGNUS — anchor recovery
Out of the mud, within SWL — a suction caisson from firm clay.
CYGNUS — storm tethering
Every wave, within SWL — a TLP tendon pretension line through a storm window.
ANTARES — resonance passage
Through resonance, in control — a flooded suction pile past 1,300 m.
Go deeper
CONSTELLATION’s lane in the Knowledge Hub
KB · METHOD
Operability screening
How a lift case becomes an operating window — the method behind the matrix.
Read → KB · PLANNINGWeather windows
What a workable window means for vessel time, scheduling and cost.
Read → KB · FUNDAMENTALSDynamic amplification factor
What DAF means, how it is calculated — and what drives it in offshore lifts.
Read →
Screen your operation
Send your lift case.
Send us the structure, the vessel and the site, and we’ll model the lift and return the operating window, the governing limit and the recommended compensator setup.
CONSTELLATION results are engineering predictions screened to DNV-RP-N103 and our ND-DS basis on the supplied metocean — not a certified analysis. The operating window is confirmed against project metocean and the contracted vessel before issue.
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