This project will evaluate stud-mounted swivel hoist rings as a replacement for the current fillet-welded temporary padeyes. NMC photo
The Navy Metalworking Center is working on a ManTech Rapid Response project that is developing and evaluating an alternative to the current temporary padeyes used during submarine overhauls.
The current padeye design used at Portsmouth Naval Shipyard (PNS) is fillet welded and requires 160 man-hours of labor to install and then remove. NMC is working with PNS and the other naval shipyards on an alternative design that would reduce labor and material costs. The leading candidate for this application is a swivel hoist ring mounted on a threaded HY-80 stud. NMC will evaluate the suitability of commercially available swivel hoist rings and develop recommendations for installation and removal.
Based on PNS data, the potential cost avoidance per overhaul is $235,000, which includes reducing the labor associated with installing and removing padeyes. Installation and removal of padeyes affects the special hull treatment, internal hull insulation, and extensive non-destructive testing. Over a five-year period, the estimated cost avoidance is approximately $2.4 million.
Implementation will require approval from shipyard Lifting and Handling authorities and procedural changes. The solution will be implemented at PNS in June 2012 for the overhaul of the USS Topeka (SSN 754). The other three naval shipyards are also expected to implement the results of the project.
The Integrated Project Team for this effort includes NAVSEA 04X, PNS , Norfolk Naval Shipyard , Pearl Harbor Naval Shipyard and Intermediate Maintenance Facility , Puget Sound Naval Shipyard and Intermediate Maintenance Facility, and NMC.