Offshore Crane – Knuckle Boom Crane with Active Heave Compensation

Marine Crane designs and builds offshore knuckle boom cranes in Türkiye for platform supply vessels, offshore construction vessels and wind farm service ships. Each crane is engineered around the vessel: deck position, required safe working load (SWL), outreach and the sea states it has to work in.

Active heave compensation (AHC) pays the wire in and out against the vessel’s vertical motion, so the load stays steady during subsea lifts and transfers to platforms and turbines.

OFFSHORE KNUCKLE BOOM CRANE
3D model of the offshore knuckle boom crane
3D design model
General arrangement drawing of the knuckle boom crane
General arrangement
Finite element stress analysis of the knuckle boom
FEA stress analysis

Technical specifications

Reference SWL 25 t at 15 m
Capacity range SWL 1–50 t
Main boom 18.4 m
Knuckle boom + telescope 14.2 m + 4.2 m
Maximum outreach Up to 35 m
Tilting moment Up to 10,000 kNm
Hydraulic pressure 250 bar
Heave compensation Active (AHC), ±2.4 m/s rope speed
Construction Pedestal, slew ring, hydraulic cylinders, bolted connections

Features

  • Active heave compensation with accumulators and live heave readout
  • Proportional control of slewing, main boom, knuckle, telescope and winch
  • Load cell with SWL-at-radius indication and overload alarm
  • Operator cabin or remote control panel
  • Start-up sequence with hydraulic and electrical interlocks
  • Sea-state derating for vessel-to-platform lifts

Capacity range and options

Offshore knuckle boom cranes are offered from about 1 t up to 50 t SWL. The final rating, outreach and load chart are calculated for each project and vessel.

Options include active or passive heave compensation, personnel lifting configuration, cabin or remote control, and low-temperature or explosion-proof equipment.

Typical vessels and applications

  • Platform supply vessels (PSV)
  • Offshore construction and subsea vessels
  • Wind farm service and installation vessels
  • ROV and survey vessels
  • Barges and work platforms

Engineering details

Structure and slewing

  • Box-section booms in high-strength structural steel
  • Large-diameter slewing bearing with external gear and hydraulic slew drives
  • Pedestal and foundation loads supplied for the shipyard’s deck reinforcement

Hydraulics and winch

  • Electric-driven hydraulic power unit with proportional valve control
  • Load-holding (counterbalance) valves on all cylinders
  • Main winch with spring-applied brake; AHC driven by vessel motion reference unit (MRU) input and accumulators

Safety systems

  • Load moment limiter with SWL-at-radius display
  • Slew, luff and hoist limit switches and emergency stop
  • Emergency lowering and overload protection options (AOPS/MOPS)

Testing and documentation

  • Static load test with test weights according to the applicable class or national rules (for cranes up to 20 t SWL typically 1.25 × SWL)
  • Functional test of all motions, limits, brakes and the emergency stop
  • Delivered with general arrangement, load chart, hydraulic and electrical diagrams, foundation loads, operation and maintenance manual, spare parts list and test certificates

Frequently asked questions

What is active heave compensation on an offshore crane?

The winch automatically compensates the vertical motion of the ship, so the hook and load stay almost still relative to the seabed or platform. It is used for subsea lifts and transfers in waves.

Which capacities do you build?

Offshore cranes from about 1 t to 50 t SWL, with outreach up to 35 m. Tell us the SWL and radius you need and we size the crane.

Can you show the crane before production?

Yes. We build a 3D model and an operating simulation from the design, so the owner and crew can check reach, clearances and the lifting sequence before fabrication.

Related pages

Request a quotation

Send the vessel type, required SWL and outreach. We reply with a preliminary load chart and an offer.

Phone: +90 530 662 66 45
Email: info@marinecrane.com.tr
Address: Pendik / İstanbul, Türkiye

Quotation request form

Fill in the form and our engineers will reply with a preliminary load chart and an offer.

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