Epoxy will work great but be sure to wash the inside of the tank after
it cures. There will be a residue you need to clean off.

Don't use west though- it is over rated and extremely expensive. If
you are in the US you can order a 2-1 epoxy from Joes auto body and
marine supply 1-954-527-9200. They have other stores but I only have
the Fort Lauderdale number. Ask for the 2-1 and make sure you get the
guy on the phone to check 3 times that he has part A and part B. These
guys are good at what they do but they breathe that junk all day and
are a bit high most of the time - no joking. They also have the best
price I have found on cloth especially when you buy an end lot.

May your anchor be tight, your corks be loose, your rum be spiced and
your compass be true.
--
Captain Danny Taddei