When a team of Puget Sound Naval Shipyard & Intermediate Maintenance Facility planners was gearing up to replace the tubing on a US Navy aircraft carrier reboiler, a work leader from Shop 26, Welders, asked herself if there might be a better way to complete the job . After thinking through the problem, she suggested the team try doing the job much differently than “the way we’ve always done it.”
Tracy Hartz, who started as a PSNS & IMF helper-trainee eight years ago, suggested cutting away a much smaller portion of the reboiler tank to access the tubing inside. This suggestion eventually resulted in an estimated 4,400 labor hours saved — every time the team does this job.
The reboiler looks a bit like a large barrel with rounded ends. Previously, a team of workers would cut off the entire rounded end of the tank, known as a head, and stow it in the ship while the internal components were removed and serviced. When the entire head was removed, a “Dutchman ring” had to be brought through the ship to be used in the reinstallation of the head.
A Dutchman ring is an extra strip of tank material used to fill in the space where the head removal cut was made.
Hartz suggested a “shield cut,” which is basically a window cut on the end of the tank just large enough to pull out the tubing. “Initially I brought the suggestion up to my supervisor Aaron Cohagan and my work leader Taylor Miller during the routine inspections after reviewing one of the drawings,” said Hartz, a graduate of the PSNS & IMF Apprentice Class of 2019.
“Then I called up my former supervisor Mikki Miller, who I learned almost all of my reboiler knowledge from. They all strongly encouraged me to approach engineering, so I sat down with Justyn Radford in Code 260, Fluid & Mechanical Engineering and Planning. We discussed the idea and how to move forward and route it through the correct channels.”
According to Ron Cenicola, non-nuclear director, Shop 26, the smaller section of the tank removed can be stored more easily out of the way aboard the vessel. Also, not having to bring a large steel ring all the way through the vessel to where the reboiler is located creates a variety of savings.
“The labor savings are the result of eliminating the need to cut large interference — due to the smaller size of the new access cut — and eliminating the need to establish a rigging path for the Dutchman ring,” Cenicola said. “Additionally, the overall length of the new cut versus the old cut is less than half.”
After Hartz first suggested the process change, a team comprised of representatives from several shops and codes came together to see if the change was feasible and if it might prove better than the existing way of doing things.
“There were a lot of up-front meetings and discussions on the design aspects of the new method with NAVSEA tech warrant holders, Code 138 and Code 260,” said Ben McCreary, non-nuclear branch head, Code 138.2 and 138.3, Non- NuclearWelding. “Once we had alignment on how to proceed, Shop 11 (Shipfitters), Shop 26, Code 135 (Non-destructive Testing Division), Code 138 and Code 260 provided out the process on a mockup.”
According to Steve Dibert, Shop 26 superintendent, Nathan Kerns, a mechanical engineer with Code 260; Code 138’s Kiichi Harada, laboratory engineer, Nicole Leraas, non-nuclear engineer, and Matthew Brodbent, test examiner; as well as Kent Burton, non-nuclear director of Shop 11, were all crucial to helping develop a workable process change from Hartz’ initial suggestion.
Hartz said her previous experience with reboiler inspections and servicing helped her understand what a large undertaking it is to cut off a reboiler head; have if lifted off the component; bring in the Dutchman ring; fit it all back together and weld it into place with the head; before final inspection and reinstallation of all interferences from moving the Dutchman ring.
“I have been involved with three re-tube evolutions; two on USS Nimitz (CVN 68) and one on USS Carl Vinson (CVN 70),” Hartz said. “I’ve also worked with Code 135 and Shop 56, Pipefitters, to perform the periodic inspections of the welded head joints and the steam head lifting lugs on the Nimitz, Carl Vinson, USS Theodore Roosevelt (CVN 71) and USS Abraham Lincoln ( CVN 72).”
“I truly believed there was a more cut-and-dry way to do the reinstallation of the welded head that would streamline the process to get us in and out of there faster,” Hartz continued. “When uninstalling and reinstalling that head for the re-tubing evolution, there’s a lot more that goes into it than people may assume.”
According to Cenicola, after much planning and some practice on a full-sized reboiler mock-up in Building 460, a new process was approved and tried out for the first time on the recent USS Ronald Reagan (CVN 76) availability in Yokosuka, Japan .
“I haven’t had a chance to talk to the mechanics about it, but I’d hope it made the process much faster and easier,” Hartz said. “Our non-nuclear director and superintendent have given very positive feedback about the change in process. Our shop and shipyard were very well represented by the entire team who went on the trip. Shop 26, Shop 11, Shop 56, Code 135, Code 260, and Code 138 were all responsible for the success of the job. Also, Shop 57 (Insulators), Shop 64 (Shipwrights), Shop 71 (Painters, Blasters and Tilesetters), Code 740 (Riggers), and Shop 99 (Temporary Services), all provided excellent support services for the job to be completed. ”
Hartz has a suggestion for anyone else who thinks they have a solution to a problem.
“Pursue it if you truly believe in it,” she said. “There are times where people don’t fully understand what happens on the deck plates and how our shop processes work. Make them see your vision by backing up your suggestion with knowledge and experience, presenting it professionally, and keep the ball rolling even if the first response you get is ‘no.’”