Most planned dockings have tight schedules, and timely replacement of vital propulsion parts is crucial. MarineShaft understands the urgency of these situations and is dedicated to solving any emergency swiftly.
Their strategy includes maintaining a large stock of raw materials with class certificates and European Origin to ensure the shortest possible delivery times for both repairs and replacements.
MarineShaft recently completed a repair job for the famous National Geographic Explorer, a vessel that sails in the waters of Antarctica during winter and the Arctic in summer. While in drydock in Denmark, on-site run-out measurements revealed deflection in both the propeller and intermediate push rods, each measuring about 12 meters in length and Ø90 mm in diameter.
The Repair Process
The push rods were sent to MarineShaft’s workshop in Hirtshals for cold straightening, a specialized process that restores bent shafts to their original condition without the need for heat.
This repair case also included the manufacturing of new push rod assembly flanges. MarineShaft’s in-house facilities, complete with a stock of raw materials, ensured rapid manufacturing. The intermediate push rod was also modified with bronze liners, which were delivered from the manufacturer.
In just four days, the work was completed and received class approval from the classification society DNV.
Facts about cold straightening.
Cold straightening is a specialized process that restores bent shafts to their original condition without the need for heat. MarineShaft, a leader in this field, specializes in the technique, which is fully approved by all major classification societies. Their method involves the use of a hydraulic press capable of exerting up to 8,000 tonnes of force, straightening shafts ranging from 20 mm to 1,500 mm in diameter, regardless of length. The work is truly craftsmanship and requires years of know-how and training.
MarineShaft’s pioneering expertise in cold straightening is backed by years of experience. Their service has been recognized since 1972 when Bureau Veritas first approved their cold straightening method.
The advantages of cold straightening are numerous and include:
- Permanent Repair: Classified as a permanent solution, the process returns shafts to a near-new condition, with a maximum deviation of just 5/100 mm.
- Speed: Often, repairs can be completed within few days, minimizing downtime.
- Cost-Effectiveness: It is a more economical alternative to manufacturing new shafts.
- Material Integrity: The metallurgy of the shaft material remains unaltered, ensuring longevity.
- Environmental Impact: Cold straightening is an eco-friendly option, significantly reducing CO2 emissions compared to new production.
MarineShaft’s services have a global reach, with shafts being straightened from all corners of the world. The universal approval of their technique means that wherever a vessel suffers propeller or rudder damage, cold straightening often emerges as the most profitable solution. MarineShaft is based in Denmark and receives rudder and propulsion equipment from all over the world.
Our hydraulic press can press with 8,000 tonnes.
