Coldwind

I found the following markings on the tank: Sherwood 3329 S12; Helco model 50

I've heard that they don't make this type of propane tank anymore. My worry is that mine might break and I won't be able to replace it. And if it breaks I won't have any heating and can't use my gas stove. So I might not be able to use my RV very long. Does anyone have any suggestions on how I can mitigate this problem? Otherwise I might sell my RV even though I recently bought it. Thanks for any help or ideas on how I can get a tank replacement.