kthoennes
Guru
- Joined
- Oct 11, 2013
- Messages
- 2,474
- Location
- USA
- Vessel Name
- Xanadu
- Vessel Make
- Mainship 37 Motor Yacht
Warning, long story ahead but a huge Shazam! moment for me.
I've had three persistent problems on this boat (well, at least three, but three that have been stubbornly annoying). One was a horrendous foul odor every time we ran water through the hot water heater. Thanks to the advice on here, we ordered a new Albin Marine water heater -- online -- with a ceramic coated stainless tank and now the hot water smells like an Alaskan mountain stream (without giardia). That left two other problems -- we keep getting water in the fuel tanks and the holding tank still stinks. I've been wresting with those problems forever. On the holding tank stink, we tried new vent line filters, removed the vent line filter entirely, checked the hoses, fine, they're clear braided hose, I can see they're clear, I made sure the vent line fitting at the top of the tank was clear (that was fun). And then for the fuel problem, we replaced the deck plate caps, replaced the O-rings, lines looked fine, fresh gas at the marina, we've gone through a ton of fuel filters which would fix the problem for a while but then the problem would come back, so new filters again. Okay, some condensation I suppose, maybe over the winter, etc. but I could never figure it out.
So in the meantime the cheap plastic (nylon?) external portions of the thru hull vent fittings have just about completely disintegrated from U/V exposure, so I thought I'd replace them all. We have four of them. Started on the port side because I can get to those easiest by removing a panel behind the salon couch. First time I've ever taken that panel off. NOW I UNDERSTAND BOTH PROBLEMS!!!
The two thru hulls I'm replacing first are about 1/3 of the boat length from the stern. I correctly assumed one was the holding tank vent line, and then I have this unidentified gray hose with a lower end just flopping around loose, one end laying in the bilge, that runs up next to the holding tank vent line. I assumed it was an extra or optional bilge pump hose, or maybe went to some long-removed something in the past and was just an orphan. So when I pulled the salon panel -- well. One thru hull was indeed the holding tank vent line. It went to an odd-looking black plastic 90-degree fitting almost against the hull with no identifying marks except "Patent US 4877152A" which then went to the thru hull fitting itself against the hull. Turns out that unidentified gray hose flopping around in the bilge went to nothing -- runs from the bilge up through an access hole and goes to nothing, hangs into empty space behind the salon couch. The other vent thru hull fitting -- that's the fuel vent line, which to my surprise is nowhere near the fuel deck plate. It just goes to a wide-open, unrestricted (and now crumbling) thru hull fitting to the outside. I googled the patent number on the black plastic thing on the holding tank line -- it's a screened, completely plugged, protective fuel tank vent fitting by Attwood. Now I get it -- at some point, somebody swapped those two vent lines to the wrong, side-by-side thru hulls. The holding tank vent line was completely blocked by a plugged, screened *fuel* vent line fitting, and the fuel tank was wide open to rain and spray while underway, running to the wrong, open, unprotected holding tank thru-hull. At some point, somebody swapped the two thru hulls which are just 3" apart, side by side.
So after all that, it is so crystal clear to me -- I don't know how in the world anybody ever maintains complex boats without helpful, knowledgeable members on internet forums like this, or without the internet in general which can tell me what Patent US4877152A was all about. The 'net may be evil in lots of ways, but today it solved two -- I thought separate -- years-old problems I just could not figure out. So thanks to all of you who generously donate your time on the 'net, and thanks to Google and other corners of the Evil Internet. I can't imagine how we maintained boats in the olden days, like the late 1980's or early 1990's.
I've had three persistent problems on this boat (well, at least three, but three that have been stubbornly annoying). One was a horrendous foul odor every time we ran water through the hot water heater. Thanks to the advice on here, we ordered a new Albin Marine water heater -- online -- with a ceramic coated stainless tank and now the hot water smells like an Alaskan mountain stream (without giardia). That left two other problems -- we keep getting water in the fuel tanks and the holding tank still stinks. I've been wresting with those problems forever. On the holding tank stink, we tried new vent line filters, removed the vent line filter entirely, checked the hoses, fine, they're clear braided hose, I can see they're clear, I made sure the vent line fitting at the top of the tank was clear (that was fun). And then for the fuel problem, we replaced the deck plate caps, replaced the O-rings, lines looked fine, fresh gas at the marina, we've gone through a ton of fuel filters which would fix the problem for a while but then the problem would come back, so new filters again. Okay, some condensation I suppose, maybe over the winter, etc. but I could never figure it out.
So in the meantime the cheap plastic (nylon?) external portions of the thru hull vent fittings have just about completely disintegrated from U/V exposure, so I thought I'd replace them all. We have four of them. Started on the port side because I can get to those easiest by removing a panel behind the salon couch. First time I've ever taken that panel off. NOW I UNDERSTAND BOTH PROBLEMS!!!
The two thru hulls I'm replacing first are about 1/3 of the boat length from the stern. I correctly assumed one was the holding tank vent line, and then I have this unidentified gray hose with a lower end just flopping around loose, one end laying in the bilge, that runs up next to the holding tank vent line. I assumed it was an extra or optional bilge pump hose, or maybe went to some long-removed something in the past and was just an orphan. So when I pulled the salon panel -- well. One thru hull was indeed the holding tank vent line. It went to an odd-looking black plastic 90-degree fitting almost against the hull with no identifying marks except "Patent US 4877152A" which then went to the thru hull fitting itself against the hull. Turns out that unidentified gray hose flopping around in the bilge went to nothing -- runs from the bilge up through an access hole and goes to nothing, hangs into empty space behind the salon couch. The other vent thru hull fitting -- that's the fuel vent line, which to my surprise is nowhere near the fuel deck plate. It just goes to a wide-open, unrestricted (and now crumbling) thru hull fitting to the outside. I googled the patent number on the black plastic thing on the holding tank line -- it's a screened, completely plugged, protective fuel tank vent fitting by Attwood. Now I get it -- at some point, somebody swapped those two vent lines to the wrong, side-by-side thru hulls. The holding tank vent line was completely blocked by a plugged, screened *fuel* vent line fitting, and the fuel tank was wide open to rain and spray while underway, running to the wrong, open, unprotected holding tank thru-hull. At some point, somebody swapped the two thru hulls which are just 3" apart, side by side.
So after all that, it is so crystal clear to me -- I don't know how in the world anybody ever maintains complex boats without helpful, knowledgeable members on internet forums like this, or without the internet in general which can tell me what Patent US4877152A was all about. The 'net may be evil in lots of ways, but today it solved two -- I thought separate -- years-old problems I just could not figure out. So thanks to all of you who generously donate your time on the 'net, and thanks to Google and other corners of the Evil Internet. I can't imagine how we maintained boats in the olden days, like the late 1980's or early 1990's.
