Rudder problems can affect a vessel’s maneuverability and require careful inspection before the source of movement can be confirmed. During a July 2026 attendance at Pier 94 in San Francisco, the NORD VENTO required a detailed marine rudder repair after the rudder was reported to have moved approximately 13 degrees on the rudder stock taper. The work involved berth preparation, temporary access arrangements, controlled lifting, hydraulic release, inspection, refitting, welding, testing, and final protective coating.
Preparing the Berth and Work Area
Before mechanical work could begin, the repair required a suitable working environment alongside the vessel. Two cofferdams were prefabricated to provide water-level access to the rudder, while a lay berth, security arrangements, insurance requirements, and fendering were coordinated through the Port of San Francisco.
Two barges were also positioned with contractor equipment, manlifts, and lighting required for the repair. These preparations created the access and support needed to perform extensive rudder work without moving directly into a dry-dock environment.
Establishing Safe Conditions for Rudder Work
Hot work around a vessel requires controlled preparation before cutting or welding begins. A Marine Chemist was brought in to gas-free the aft section of the vessel and confirm that the cargo tanks were inerted. Plugs were removed from the top of the rudder, and openings were prepared so the internal rudder spaces could also be gas-freed before hot work started.
Cofferdams were then fitted to both sides of the rudder. Four pad eyes were welded to the top of the rudder to receive four 20-ton chain falls. Dye penetrant testing was completed on the pad-eye welds, with no indications reported. The photographs on pages 6 through 8 of the service report show the manlift, cofferdam, and chain-fall arrangements used around the rudder.
Inspecting the Cause of Rudder Movement
Before lowering the rudder, the team inspected the indicator bar on the rudder nut to determine whether the nut had moved in relation to the rudder. The indicator had not shifted, which indicated that the rudder itself had not twisted.
After access doors and inspection plates were removed, the inspection confirmed that the rudder had moved approximately 13 degrees to port on the taper. Divers were then used to examine and video the rudder surface. Mud deposits were observed on the starboard side, which the service report identified as the probable cause of movement between the rudder and rudder stock taper fit.
Releasing and Examining the Rudder Stock Taper Fit
With the rudder weight supported by the chain falls, the locking bar was removed and the rudder nut was released into the void space. The hydraulic taper fit between the rudder stock and rudder was then released, allowing the rudder to be lowered enough to inspect the taper contact surfaces.
Inspection through the port-side access opening found no major scoring or damage. Only slight marks were reported, which required polishing with Scotch-Brite and emery cloth. The photographs on pages 12 through 14 document the controlled lowering process and the opened port-side inspection area.
Refitting and Securing the Rudder
Once inspection and surface preparation were complete, the rudder was reinstalled under the direction of the on-site technicians. A dry fit was carried out first so measurements could be calculated before the final hydraulic fit.
During the final installation, the rudder remained on the hydraulic nut for 30 minutes before release. Measurements were taken with the Hyundai technician, after which the nut was tightened, secured, and fitted with a welded keeper bar. The port-side indicator bar was also painted bright red to improve visibility through the sight-glass viewport.
Closing, Testing, and Sealing the Repair
Completing a ship rudder repair requires more than returning the rudder to position. Hydraulic fitting plugs were reinstalled to prevent seawater ingress; moisture-collecting bags were placed inside the void; and removed plugs were sealed with approved marine epoxy putty. Temporary rigging and welded lifting pad eyes were then removed.
All inspection openings were refitted to their positions and welded closed by certified welders after approval by the NK Surveyor. Ultrasonic testing was performed at the corners of the port-side shaft inspection location, while the remaining welds underwent dye penetrant and vacuum box testing. The report states that the testing was witnessed by the Class NK Surveyor and passed.
Restoring Surface Protection Before Departure
Areas of bare steel created during the repair also required protective coating. Two coats of primer were applied with three-hour drying intervals, followed by two coats of antifouling coating with six-hour intervals between applications.
More than 12 hours were allowed to elapse before ballast operations began, so the vessel could be returned to its arrival condition for departure. Port authorities were also notified in advance, and the required documentation was prepared to prevent unnecessary departure delays. The repair sequence concludes with a photograph of NORD VENTO departing Pier 94 on page 27 of the report.
Conclusion
A major rudder repair requires coordinated access, controlled lifting, accurate inspection, hydraulic fitting, certified welding, testing, coating, and communication with port and class representatives. In the NORD VENTO project, the repair team worked through each stage from investigating the reported 13-degree rudder movement to refitting, testing, sealing, and preparing the vessel for departure. The project demonstrates how organized marine rudder repair work can address complex steering-component issues while maintaining documented inspection and quality-control procedures.
For professional ship repair support involving rudders, structural work, welding, inspection, and complex port-side repairs, discuss your vessel requirements with Oceanwide Repair.