BREMERTON, Wash. –
Several years ago innovative thinkers in Shop 26, Welders, and Code 138 Welding Engineers, developed an innovation to improve how rudder bores are serviced at Puget Sound Naval Shipyard & Intermediate Maintenance Facility. Transitioning from hand welding inside the rudder bores to automated welding cut the time to repair or restore aircraft carrier rudder bores in half, but there was still room for improvement. While using two different automated welders is faster and more precise than having human welders crawl into these tight and inevitably hot spaces, setting the machines up quickly to do the precise work still posed challenges.
During a Lower Rudder Thordon Bearing Repair, which is informally referred to as a rudder bore repair, worn down rudder bores are built back up with both ferrous and non-ferrous materials, so the rudder stock holding the rudder fits within a .002-inch tolerance at three specific spots along the shaft. This tight tolerance helps reduce the amount of wear and tear on the bore from sediment and salt water getting into the spaces between the bore and rudder.
Mechanized pulsed gas metal arc welding, known as GMAW-P, is used to build the steel back up to specification with a Bore Repair Systems BOA-550HD, or BOA for short. After steel build-up is complete, mechanized pulsed gas tungsten arc welding, or GTAW-P, equipment is installed to clad Monel bands over the steel in three high-friction spots. Monel cladding is a nickel alloy layer that is more resistant to corrosion than steel is. It is placed over the steel on the parts of the rudder bore that actually touch the rudder shaft.
According to Josh Maya, Waterfront Support and welding work lead, Code 100TO.3, Moonshine Lab, the new GTAW machine could not reach the lowest portion of the rudder bore, where the third Monel cladding band needed to be welded. The machine needed to be relocated to the bottom of the bore to do the lowest weld.
This greatly increased the set up time and the complexity of the work. The only other choice was to manually weld the third band of non-ferrous material by hand.
To avoid hand welding or a second set up, the Moonshine Lab was asked to provide a couple of solutions to improve the set ups for the machines.
“We designed and built an adapter that the bore welder can be mounted onto that allows it to be lowered two feet into the bore hole, so that the lower band can be welded,” said Maya. “This adapter also serves as the main platform for [the GTAW machine] to weld the upper bands. It being the sole platform needed to do the welding reduces setup time.”
Precision and convenience were also necessary for the equipment used to build up the rudder bore. Due to the double swing arm design of the BOA welder, the weld head could be difficult to properly center within the bore.
When workforce members from Shop 26 started talking with the Moonshine Lab, it became clear two devices needed to be designed to improve multiple parts of a bore rudder repair job.
Nate Wims, general foreman, Shop 26, Welders, and Josh Hughes, training leader, Shop 26, Welders, asked the Moonshine Lab if they could also design a targeting fixture for the BOA that would allow welders to precisely center the welding assembly inside the rudder bore. At around the same time, Kevin Boyle, production technology branch head, Code 100TO.3, was having conversations with Shop 26 about the welding machine mounting problems.
“All we had were conversations about the problem, and we came up with the idea of a platform that could be lowered into the bore,” said Maya. “We came up with the overall design in-house." The targeting fixture was designed in-house as well, he said.
According to Maya, the improvement project was a team effort within the Moonshine Lab. He and Darryl Barr, now retired, designed and built the Bore Welding Adapter together. The initial drawings were hand drawn by Maya before Randy Callahan, a Moonshine Lab draftsman, used Solid Edge 3D Computer-Aided Design software to capture the work. Maya worked with Danny Ortiz, another Moonshine Lab draftsman, to design the BOA targeting fixture, before Maya built the first prototype.
“We built them a clamp-on fixture, which allows them to quickly and precisely set up the BOA welder,” said Maya. “It has cut their setup time from potentially half a shift, down to as little as half an hour.”
The Moonshine Lab worked with Shop 26 and Code 138 to refine the design, after testing it on a rudder bore mock-up.
According to Josh Hughes, welder training leader, Shop 26, the communication skills and problem-solving ability of his Moonshine Lab collaborators helped the project come together quickly and effectively.
“It was easy to work with the moonshine lab,” Hughes said. “(Maya) is really passionate on creating solutions for our problems. The targeting device saves the shop time and money on the set up of the BOA welder, both in training and on the boat, while also making a more complicated task much simpler.
According to Maya, both products continue to improve the way Shop 26 refurbishes and repairs rudder bores on aircraft carriers.
“Welding from the top not only saves a huge amount of time, it puts less strain on the welders,” he said. “It can also be more precise, as the base plate has integrated leveling bolts. The BOA targeting fixture saves time and ensures weld quality due to a more precise centering setup, which then equates to a more consistent weld contour.”
To learn more about the initial transition from hand welding rudder bores to automated welding, read “Collaboration leads to CVN rudder bore repair savings,” from the June 23, 2022, issue of Salute, at www.navsea.navy.mil/Media/News/Article- View/Article/3070111/.