Page 156 - ΝΑΥΤΙΚΑ ΧΡΟΝΙΚΑ - ΣΕΠΤΕΜΒΡΙΟΣ 2022

POLAR RESEARCH VESSEL

“SIR DAVID ATTENBOROUGH”

READY FOR ANTARCTICA

ADVENTURES

Plowing through polar ice exposes the risk of inspection was carried out before laser cladding.
damage to a ship´s propulsion and steering The spots/marks were repaired by micro welding
equipment. - a welding technique that is ideal for smaller
The 2021 British build one-of-a-kind research imparks/spots.
vessel “Sir David Attenborough” has completed After machining the damaged areas on the rud-
extensive sea trials, and her first trip to Antarctica. der stock's lower cone and the rudder stock´s
At a yard stay at Orskov Yard in Denmark this sum- upper journal, we welded up the areas by laser
mer, damage to the rudder equipment was con- cladding. Rebuilding damaged areas by laser
firmed. The cause of the damages found on the cladding is a very fast and accurate welding
rudder equipment remains unknown, but Marine- method.
Shaft got the order for repair of the rudder equip- After the laser cladding process, the rudder
ment, which was sent to MarineShaft´s workshop stock was machined, and NDT tests were car-
facilities in Hirtshals, Denmark. ried out ensuring that everything went according
Case: The rudder stock had turned inside the to class regulations, which in this case was LR.
steering gear leaving scratches and marks on the
upper part of the rudder stock. Furthermore, the Rudder blade
rudder blade and rudder stock connection had suf- The damages inside the rudder cone were
fered damage. The dimension of the rudder stock machined and fitted to the new dimension of
was Ø639 x 5720 mm. the rudder stock cone.
Before returning the equipment, the rudder stock
Rudder stock was treated with rust protection. On-site Marine-
After MarineShaft’s inspection/measurements of Shaft assisted the yard with mobile machining of
the rudder stock, the steering gear rotor inner the rudder trunk.
sleeve was removed. The rudder stock´s lower
cone had been damaged. Go to MarineShaft.com for more information or
MarineShaft has class approval to carry out class use the contact details below.
approved laser cladding and micro welding, and MarineShaft A/S - Pier 2, 9850 Hirtshals,
both “cold” welding techniques were used for Denmark
this repair. The damaged areas were machined Phone: +45 96560202
and prepared for welding, and liquid penetrant Email: info@marineshaft.com

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