I suspect my sentiment is a common one. I have owned Tranquility Base for 4 years now, and I am STILL finding stuff the Previous Owner did wrong, usually as a cheap-out shortcut. The latest find is particularly aggravating.
I have had a slow potable water leak into the bilge ever since I bought the boat. Until recently I have been unable to track it down, but I had a brainwave -- what about the shutoff valve on the tank itself? Sure enough, it was loose.
The loose valve was also a cheap Ace Hardware plastic plumbing valve. Suspicious! I suppose it matches all that stiff gray house piping he/she/it used all over the place when doing a plumbing "upgrade."
I took it all apart, stripped the shreds of old plumber's tape off the valve, put on new plumber's tape, and threaded it back in (by feel -- you can't see the tank threads). As I tightened it by hand, all of a sudden it got looser. Yup, stripped thread, and not on the darn valve -- its threads are perfect.
Ugh! I think the tank must come out. The tank is in the Starboard settee. In fact, the settee looks like it was built around the tank. There is about a half inch clearance everywhere. I'll have to remove all the tank's fittings to have even a prayer of getting it out, so I am in for more contortions or else settee disassembly.
The water tank is poly and is original to the boat - a model B145 made by Ronco Plastics. I checked w/o much hope but was delighted to find they are still in business, operating out of California! I called them for advice – they told me all fittings are straight thread, and the threaded part will probably be replaced. But – they are spun-welded onto the tank (whatever that is). Looking at the cheap Ace valve, it appeared to have a bit of a taper to it. I tried a proper valve with marine tubing and an appropriate, plastic straight threaded nipple, but no joy. It still jumped threads while hand tightening, and it still has a slow leak (but it is even slower).
My new best friends at Ronco Plastics helpfully provided the name of a company in Rhode Island that can spin weld a new fitting, thinking that it will be cheaper to ship it there than all the way from coast to coast. They think that would be considerably cheaper than $350 plus shipping for a new tank.
So now I am in a quandary. My choices are:
1) Just replace the 28 year old tank with a new one on that is exactly like it? (Ronco still makes it)
2) Send the old tank out for repair
3) Try to find some goop that will seal the fitting and provide some gluing factor since the fitting can't be tightened?
I am rejecting 3) out of hand. You have to be able to get the fittings off to remove the tank, and it will contact my drinking water! So what would you do -- 1) or 2)?
PS: And thanks for listening to my rant.