Thanks for all comments so far. They are helpful. My problem is that the leak opened up in Sitka, Alaska, two weeks ago, so I had to leave Puffin up there for the repairs. The estimate from a respected shop is $24k!!!. that represents about 50% of the value of the boat. That would include engine removal and two new aluminum tanks. I have confidence that the repair would be very good but naturally, I am looking for other options. If the boat were near my home I would do it myself but that is not an option. The decision on what to do is compounded by the fact that I will turn 75 years old this year and recognize that I will not get many more years of use out of Puffin. Not in Alaska anyways. Unfortunately, I am spoiled by cruising those unpopulated waters (25 years so far) and have little interest to going south into the more crowded waters near Seattle and Vancouver. After the plywood encasements around the tanks are removed I will know more about what kind of leak is present. I suppose it will be at the bottom of the tank. Please keep your suggestions coming. Richard