jtseng123 for 'full' R-stamp repairs, or any Alterations your R-stamp Repair contractor will attach another, R-Stamp, plate. If the Code Data Plate bracket is big enough, they will attach the Repair plate beside/below the original U-stamp plate. And an R-1 form for Repairs, or an R-2 for Alterations will be completed and signed by the contractors QC Mgr and their AI.
If the Repair contractor's AI deems that the repair is inconsequential enough, and 'calls' it a Repair-of-a-Routine-Nature, only the R-1 form is completed. No R-stamp data plate required.
Some of the above folks are over-interpreting API-510 and NBIC on the subject of hydro. If the repair area is truly a pinhole, the only way the contractor's AI will require a full hydro is if he is VERY unsure of himself, is mad at the contractor, or mad at you. The purpose of a hydro is to proof-test the design and fabrication of a vessel, to make damn sure that the vessel will not go BOOM in service. Minor repairs do not change the pressure capacity of a vessel. Remember, we are allowed to add a 2"NPS nozzle without calculations or reinforcement, meaning that 2"NPS-sized holes will not hurt the pressure capacity of a vessel.