The tank has now been roughly paint stripped using a wire rotary brush on an electric drill, mainly to see if any other offending holes appear. The rest of the tank is fairly solid so the rotten section has been cut out ready for a plate to be welded on.
Marine clean has been poured in (about a pint) and given a good sloshing around. A hose pipe was employed to give the tank a good rinse out. John, if you are lucky enough to have a fairly solid tank, unscrew the fuel lines from the feed from the tank feed valve which site on top of the tank and remove. Chances are if you leave it in you could be in danger of getting some muck stuck up the pipes which go to the bottom of the tank. Also if you take that out you can stand the tank up on its end, put a hose in the filler neck and drain out of the hole where the feed was.