ReManufacture of Large Barge Rudder Stocks

The Challenge

SpiralWeld Ltd were approached by a new marine customer (after recommendation) to assist with ReManufacture and recovery of a port & starboard rudder off a large waste transfer barge. Both rudder stocks had suffered damage to the top end thrust bearing journal as well as corrosion and scoring along the plain bearing journal at the rudder end. Additionally, the starboard rudder was bent at the rudder end of the plain bearing journal.

Both rudders were required back urgently for installation to support the customer’s own commitment. Therefore, replacing the starboard rudder stock was not an option due to lead time to source and machine a new replacement stock. Recovery was the only option and SpiralWeld Ltd was their solution.

Solving the Problem

Careful handling was required given the condition of the rudder blades, which were heavily corroded. The rudder blades were shortened, to enable us to swing them in our largest lathe and were re-built when back at the dock. The port rudder ReManufacture offered limited challenges. The stock was straight enough to secure and set the rudder in the lathe in a suitable manner, allowing for machining and weld recovery to be completed in good time.

The starboard rudder could not be straightened mechanically. The bend at the rudder end of the plain bearing journal was to be machined true and concentric to the top end thrust journal. The rudder blade could then be re-positioned after installation into the vessel.

The starboard rudder required significant engineering to develop a safe and secure way to support the rudder end in the chuck. The bend was not in a single plane, the angle of, and length from, the bend caused a considerable offset of the stock to the chuck centre. SpiralWeld Ltd engineering was able to measure and calculate the compound angle and mirror this on the mating face of the crank offset fixture that was fabricated. The fixture was welded, strengthened and NDT inspected to ensure rigidity and integrity of the fixture during all activities, allowing SpiralWeld recovery to be completed.

A Successful Outcome

This ReManufacture process was developed during the job. By applying safety and technical risk assessment practices we ensured that at no time were personnel or customer owned parts at risk. The SpiralWeld process is a proven solution, the handling and turning of this part is where the risk existed and we were able to manage this, as a team, throughout.

Due to the urgent nature of the job, SpiralWeld personnel worked over the weekend and exhibited considerable teamwork to ensure the delivery was met.

As recovery was the only option the saving Vs replacement is immeasurable as the SpiralWeld Solution enabled our new customer to meet their critical commitment.