We did this
work couple of times, actually two of the
aluminum fuel tanks of my Nauthitec 46 have been corroded and started leaking and we had to change both of them. Unfortunately most idiot manufacturers install the
tanks in the
bilge when the
boat is wide open and you cannot take them out later in one piece. We had to cut the
galley carefully and after taking out the tanks and replacing with the new ones, we installed and sealed the buttom of the
galley. It's barely visible..
Welding the
fuel tank can be very dangereous and difficult. Moreover, if you have the pitting
corrosion (which was our case) you have plenty of small holes and you cannot
repair by welding. I know there are some chemicals to block the holes and we never tried. All will depend on what kind of holes you have, in which part of the tank and how accessable these areas from the top. Again most of the manufacturers don't even put a manhole to have acces to it. Leave alone the welding, you cannot even see inside and clean it if necessary..
Cheers
Yeloya