We have a Bowen gas hot water heater in our
1963 Bambi. It had been left with water in it from PO [previous owner] and then the water froze. Popped the seams. My husband took it out and down to our local welder and he cut off the top of the tank and inspected everything inside and then welded it back up and pressure tested it for us. Ours now works great!
If you have electric only, maybe it is your elements or something. Post pictures and maybe others will have suggestions! Good luck!
Mrs. NorCal Bambi traveling in S Tardis