I have two aluminum water tanks: an 85-gallon one amidships and a 65-gallon one forward. Both, as one should expect, had some corrosion. My forward tank had been leaking very slightly, so I knew that needed replacement. However, replacing that tank would be a huge undertaking, requiring the removal (read: major deconstruction) of the entire guest bed and drawers, plus removal of the door and frame in the forward cabin. And then, after all that, the aluminum tank would need to be cut into two pieces in order to remove it from the boat. Obviously, this also means that the replacement plastic tank would need to be a little smaller capacity to be able to get it into the boat. I know well from sailboat owners forums online that this is a very common conundrum for many boat owners, so I set out to research if a refurbishment was both possible and practical. The main problem I had was to find a coating or sealant that was certified as food safe, or suitable for potable water. I finally came across a Norwegian specialist coatings firm called Jotun. Initially, my internet search had found “Jotun Tankguard DW,” but unfortunately, it was not certified for use on aluminum. This is where the technical guys at Jotun were very helpful. They researched their archives and found that another product called Jotacote 605 was indeed suitable for application onto aluminum and had been laboratory tested and certified as food safe by the NATA (Australian government certifiers) — therefore, perfect for my water tank.