Replacing fuel tank 2000 cc21

[dockman]

Has anyone replaced the fuel tank in a 21 deep vee my 81 gallon tank is bad the floor has never been cut out so I wonder was it made to be cut out the tank line in floor my buddy left the boat sitting since 2011 was hoping to get a little Intel but the new sea pro is no help to me and I cant find someone doing it right online would like to see some pictures of someone doing theres

[freezerfiller]

There's a thread on hear where a guy did a decent writeup on the exact same boat. I think his name was markmass or markinmass or massmark.