MPR Certified for In-situ Propeller Repair

S-T Diesel and Marine Group’s associate company Maritime Propeller Repairs BV (MPR), based in The Netherlands, has obtained the DNV-GL certification to perform in-situ welding for propeller repairs. 

In recent years, MPR has invested in special welding equipment and carried out several analyses and tests in order to obtain results that comply with the requirements set by DNV-GL, the world’s leading ship and offshore classification society. The successful results of this investment have now been rewarded by class approval and certification, making MPR the only company certified for vertical welding on propellers. 

Most repairs on propeller blades require the removal of the propeller from the shaft, which necessarily includes the removal of the rudder, resulting in time-consuming and expensive operations. The innovative techniques developed by MPR, instead, allow the welding operations on propeller blades to be performed without removing the propeller, thus making repair activities more time-efficient and cost-effective, and, ultimately, competitive. 

In-situ welding repairs require more detailed investigations than those carried out in a workshop, using normal ultrasonic investigation methods. The DNV-GL regulations, however, require particular ultrasonic investigation and examination of the propeller material. MPR, together with a specialist partner, has developed a specific technique for the microstructural characterization of nickel-aluminium bronze (NAB) alloys, which are widely used in the manufacturing of propeller blades. 

Gert Hendriksen, Managing Director of MPR, tells us about the steps that lead to this pioneering technique: “two years ago we were asked by the classification society to investigate the possibility of in-situ welding in the vertical position. After personally discussing the details with DNV-GL, our company decided to undertake this challenge. We invested a lot of time and resources in this study, because we believed in the ultimate objective, which would be of great benefit to our customers when they have damaged propeller or blades. By developing this innovative method and earning the certified approval, we can now offer the complete service package when ultrasonic investigation is required by Class.”

MPR conducts repair services on propellers and propeller blades in their workshop in Drunen, The Netherlands, and also on location worldwide.