During a class inspection in Kingston, Jamaica, SGS noted severe material erosion to a container vessel’s rudder blade and rudder horn. The erosion was located on various areas of the rudder horn and blade and was so severe that it was allowing water ingress into the rudder. The attending surveyor placed a condition of class on the vessel and required that it be permanently repaired within the next month. With another two and a half years of operation in sight for the customer, drydock was not an appealing option so they requested SGS to evaluate an in-water permanent repair for this damage.
While SGS was developing a repair procedure to be submitted to class society’s damage department, material samples were taken from both the rudder horn and blade to determine its wet weld-ability. Analysis showed the blade was conducive for wet welding, but the horn was not as it required pre/post heat treatments. A strategic game plan was developed and approved by the customer and class to permanently repair these areas based on the material sample findings. This repair procedure incorporated both wet and top side welding processes using SGS approved procedures.
Weeks of logistics were discussed and planned so that the vessel could attend the SGS home port location of Tampa, Florida for a scheduled repair. the repair involved both SGS and the local shipyard. The vessel unloaded cargo and shifted additional containers to trim the vessel so that the rudder horn was out of water for surface welding operations. SGS could then repair the rudder blade in water and dewater the rudder while the shipyard repaired the rudder horn and the dewatered rudder locations in the dry. Coded Welder / Divers were flown in from multiple offices to work around the clock for the scheduled time frame. Working together as a team, both SGS and the local shipyard solved issues as a team while ensuring the best quality for the customer.
The result was that a rudder horn insert plate was permanently installed along with eroded areas were restored through “build – up” welding of multiple areas on the rudder blade and horn. All areas passed NDE requirements and both the blade and the horn were dewatered prior to the vessel departed. Class removed the condition of class and approved the repair as permanent. The vessel once again resumed its normal schedule.