I would get a friend or neighbor or two to help me if I didn't feel I could do it myself. I would be afraid of yanking out some structural member through some mishap with your chain and strap. And yes as an apprentice it's me doing it, with a song in my heart.
It's just like carrying a drunken fat chick up a flight of stairs, it's not moving Cheops.
If you're replacing 7 year old water heaters, you need to more aggressively insulate it and the pipes to keep the condensation from eating it up again.