Shock Absorption
Any operation where peak loads may arise. Cranemaster® protects the crane and the lifted structure by reducing the dynamic amplification factor (DAF) in all lifting phases.
Cranemaster benefits
- Increasing the operational weather window of the lifting operation.
- Protection of crane and lifted payload at lift-off and set-down.
- Immediate response to potential dangerous loads.
- Enabling crane to maintain its lifting capacity at increased wave heights.
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: [...]