The main advantage of a portable crane, fixed to a platform, vs a crane on a floating vessel are:
1- Precision lifting
2- Cost efficiency
Lifting vessels and barge cranes have well-known uses and advantages in the offshore industry and are suitably employed where required. However there are many cases where a lift boat or barge crane will not be suited for the situation at hand, either for technical reasons or for cost reasons or both. Firstly, our crane being secured to the platform structure mitigates dynamic issues (harsh weather & sea condition) and provides safe static lifting on deck. Secondly, Thunder Cranes offers significant cost savings versus using more expensive barge cranes and other floating vessels.
Yes. Our cranes packages are specifically designed to enable our crew to perform “Self-Lifting”. Put simply, we start with our A-frame jib which allows us to lift components of our smallest crane. Once the smallest crane is ready, it allows us to pick up components of a larger crane, and so on.
Most likely, yes. We can determine this either through review of detailed plans or a site inspection. Clients are often surprised to find that we can fit in our cranes just about anywhere.
On average a Thunder Crane can be rigged up within 12-18 working hours including the load test.
Our cranes are designed to be installed on almost all offshore platform configurations by either clamping, bolting or welding. Clamping is the preferred method since it is faster and avoids hotworks. We can safely secure cranes to a platform’s skid and main structure beams by using a clamp and stud-bolt system. This allows our cranes to be positioned quickly and efficiently, without affecting ongoing platform operations. Furthermore our clamping system allows for easy repositioning with minimal disruption to our lifting productivity.
We have a range of stiff-leg and pedestal cranes with a lifting capacity ranging from 2 to 60 metric tons. Lifting capacity onboard depends on several factors:
1- The distance from the crane at which the load is lifted which affects the angle of the boom.
2- The sea conditions when lifting from supply boat.
3- The type of structure upon which the crane is mounted.
Yes. All our cranes meet API 2C specification which is the Specification for Offshore Pedestal Mounted Cranes.
Our cranes undergo a full API annual inspection and load test every single time one of our cranes is rigged up. In some cases this may be up to 30 times a year.
Yes. Thunder Cranes provides all the operational, management, engineering and maintenance support needed to operate our cranes on a 24 hour basis.
No. Portable, modular, self-lifting cranes are a highly specialised service requiring experienced personnel. We have the most competent and experienced personnel in our field and our crews are led by seasoned superintendents each with more than 10 years of experience.
1- Framing Drawing – main deck or deck we plan to install the crane
2- Elevation Drawing
3- Main Deck Layout
4- Client’s equipment list c/w weight and dimension and layout if any
Following the site inspection our engineering team will provide a complete report on how our cranes will be rigged up, its radius reach, its load capability and how it will be secured on the offshore structure/platform. We will also provide the reaction forces from the crane for our clients to check their offshore structure/platform integrity.
Offshore lifting jobs generally involve lifting to and from offshore supply vessels and therefore all such lifts are exposed to dynamic effects due to variations in hoisting speeds, crane and vessel motions, object movements etc.
The dynamic effects will be influenced by environmental conditions such as the wave height and wind speeds, as well as rigging arrangements, stiffness of crane-boom and wire, weight of lifted object, and the lifting procedure itself. In the case subsea lifts, once an object is lowered subsea it will pick up additional forces from hydrodynamic action.
All of these factors must be identified and given due consideration when making SWL calculations, designing lifting plans and safe operating procedures.
In accordance with API 2C, three methods are given for calculating the dynamic forces acting on a crane in a specified sea-state. The methods are:
1- Vessel Specific
3- Default Dynamic
The Vessel Specific Method is only normally used by cranes on vessels or floating platforms, whereas on fixed platforms crane ratings are determined by the General Method or Default Dynamic Method (with restrictions as explained below).
Default Dynamic method is only allowed for fixed platforms in areas with mild sea and wind conditions and shall only be used in situations where the supply vessel position is maintained constant relative to the platform (such as for a platform-tethered supply vessel).
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