My tanks are 27 yrs old, and as far as I can tell are in good condition, at least on the outside, difficult to access the inside to really inspect well. I'm afraid they may look good right up to the day they begin to leak.
On mine the sole would have to come out to replace either as it appears that the water tank has to come out first and then slide the fuel tank forward to remove it, so it seems if your replacing one, replace them both.
There is a company out of Tx that replaces chain plates, I've heard it a $5K job, and the replacement plates are larger and out of a SS that is less likely to fatigue or corrode, but have also heard that Titanium is not that much more expensive and if you go Ti, you'll never have to worry.
My waste tank I could change out in a couple of hours as it's under the port Settee and the tank is slightly smaller than the access hole, so no cutting of anything. My waste tank was replaced in 02, so it's probably getting close to needing it again.
New waste tanks are I believe fiberglass
, I had thought to replace my tanks with ones made from 316L, but there are issues there too, maybe Monel? Or seeing as how the aluminum ones have lasted 27 yrs so far, if replacement ones last that long, then it's be someone else's concern by then, I'll be too old to still be cruising.
The advantage of the IP tanks is they are big and located down low and in the center of the boat, but not easy to access.
does have a rebuild
/ refurbishment program for their boats and I've good things about that, but I'm sure it's probably not cheap
I had a list of things I was sure I needed to do before I started cruising, but the more I dig into this old boat, the more I'm finding most of the systems are fine, the electrical
for example is in excellent shape