Shock Absorption
Remove peak loads in crane and rigging.
Operational Challenges
Dynamic load on crane or load at lift-off for lifts in air.
Limited operational weather window because of harsh weather conditions.
Any operation where peak loads may arise, in air and subsea.
Potential re-entry of load being lifted represents a significant risk.
Cranemaster Benefits
Increasing the operational weather window of the lifting operation.
Protection of crane and lifted structure in all lifting phases by reducing the dynamic amplification factor (DAF).
Immediate response to potential dangerous loads.
Enabling crane to maintain its lifting capacity at increased wave height.
Cranemaster® protects the crane and the lifted structure by reducing the dynamic amplification factor (DAF) in all lifting phases.
Offloading from a supply vessel or barge with and without Cranemaster®
Manifold weight: 50T • Significant wave height (Hs): 2.0m • Wave period (Tz): 8sec. • Hoisting speed: 0.3 m/s.
This Orcaflex simulation shows a lift-off situation from a barge. The crane is sitting on a fixed platform, but the principles are the same also if the crane is mounted on a moving vessel.
Without Cranemaster® (to the left):
Significant snap load during lift-off, in this case around 85T. This corresponds to a DAF of 1.7.
With Cranemaster® (to the right):
Snap load is avoided and the DAF is reduced to around 1.1.
For cranes with a slow lifting speed, there may be a risk of re-contact between the structure and the barge. Some Cranemaster® units can be equipped with a quick-lift system which will pull in the piston and thereby avoiding the re-contact.
Shock absorption since 1983
The first applications of Cranemaster® units back in the early 1980s were related to shock absorption and since then small units with SWL of a few ton up to large units with SWL of 500 ton have been developed.
Please contact us for discussions of specially designed Cranemaster® units used for shock absorption.
MOB boats, lifeboats and NORSOK R-002
Over the years Cranemaster has delivered a number of different units for deployment/retrieval of MOB, work boats, and lifeboats. In the NORSOK R-002, edition 2. issued in September 2012 there are strict rules for shock absorption during lifting of MOB boats and lifeboats.
Cranemaster® is an excellent solution to these requirements, and is well suited in cases where the use of elastic pennant is impractical or does not give sufficient dampening.
Featured References – Shock Absorption
Load chart with improved load curves
Customer Challenge: Lifting of a subsea x-mas tree with weights of 37 metric tons from a work boat to a semi submersible rig offshore New Zealand. Cranemaster Solution: A [...]
Load chart improvement for lifting of x-mas trees
Customer Challenge: Lifting of x-mas trees using a Seatrax 108 S10832 crane. Cranemaster Solution: Two Cranemaster® shock absorbers with SWL of 100 metric tons and 1 meter stroke in [...]
Lifting capacity increased for higher sea states
Customer Challenge: Increased lifting capacity for offshore rig on British sector. Cranemaster Solution: A Cranemaster® unit with SWL of 100 metric tons and 1 meter stroke. The Results: [...]