Today the bedding compound around the chain plates for the upper stays is set. This means I can reattach these stays and detach the lower stays so I can remove and inspect those chain plates. I began removing wood trim to access the four chain plates for the lower stays. There is evidence of water leaking down these, just as there was on the chain plates for the upper stays. Accordingly, I removed additional trim to see if I could find additional leaks.
A couple folks commented and others emailed about our likely choice of stainless steel for replacing our problematic stainless steel water tanks. I failed to mention we did consider polyethylene tanks and we haven’t ruled them out. In fact, polyethylene was my first choice and before we realized the leaking was getting progressively worse, I figured we would live with the leaks until we got to San Diego, find a place that made custom polyethylene tanks, and replace our two tanks with these (I don’t think we can have these fabricated in Mexico and I don’t want to wait for large, custom tanks to be shipped to us here).
Our metal tanks are wedged shaped to take advantage of the interior hull space. One is starboard and one is port, mounted symmetrically. It is difficult to see how well they use the space (there is bilge area beneath them) until I remove them. It may be that we can use the existing space in a different and effective way with multiple, rectangular-shaped polyethylene tanks, but I doubt it.
Don’t get me wrong, were I building a boat from scratch, I would configure it to use off-the-shelf polyethylene tanks. They are non-toxic and will last forever. But given where we are and the configuration we are working with, I suspect we’ll see that is straightforward to repair our existing tanks (maybe cutting off and replacing the bottom, for example) and that they make good use of the available space. I think we will then reach a conclusion about the reason these failed and move forward with stainless steel. After all, the previous tanks were stainless and were not replaced until 30 years passed (and our neighbor in the marina, Cactus Tree, is a Mariner 31 with 40-year-old stainless steel water tanks). I’m convinced it is all about installing them properly, ensuring the exterior stays dry, and preventing anything caustic (including chorine) from corroding the tank. I hope I’m right.