Software training advice

Hello All,
New to this board. I have 37 years eapierience in piping. 9 in Nuclear and petrochem. 28 building submarines.
I need to find a new job. I have been passed by technologically. Working in schematic dept at Electric Boat doing diagrams on Auto cad for about last 12 years, did layout and design on the boards for the other 15 years as a Designer checker. I have not done layouts for a while. I would like to get educated on what is being used today so I can get back into petrochem field doing layouts isos, tanks vesselels etc.
Where do I start. I need to move a quick as possible. I have Nuclear expierience back in the 70 's United Engineers, Catalytic Inc., Phila. Electric Co. etc. Pressure Vessel fabrication and skid units. Can anyone suggest where I should start to re-educate so I can change gears . Thank you kindly.
Robert