Fresh water fill / vent problem

[ttibbits]

Has anyone experience with replacing the fresh water vent hose on a 1990 Hunter 35.5?
My problem started when I found it very difficult to fill our fresh water tank. My first inclination was that the vent line was blocked. I was able to fill the tank after removing the vent hose from the tank fitting in the forward v berth.
I then set about attempting to clear the vent line. The deck thru hull fitting (located in bow anchor locker) was removed and checked for blockage (none found), when attempting to clear the hose it became clear that the line was holding a considerable amount of water. Vent was cleared using compressed air.
I then tried intentionally overfilling the tank to ensure vent works properly and realized that I now have a crack in the vent hose near the tank fitting...... my questions:

1. Having the vent line dip to a point where water collects in it seems like a poor design? Or is this to prevent backflow into the tank from tube?
2. Is it possible to replace the vent hose? I can access the thru hull fitting (port side anchor locker) via access panel in v berth, and opposite end it enters tank on starboard compartment under v berth, but not at all clear as to how it is routed around bulkhead in forward compartment.

Thank you in advance for any and all comments or suggestions.
Tim

 

[Peggie Hall HeadMistress]

A water tank vent line should have a high arch in it to prevent any sea water that manages to makes it through the thru-hull from contaminating the fresh water supply. The arch should be right before the thru-hull. (Same is true for fuel tank vent lines, btw...you don't want sea water in your fuel supply either.)

Sounds like your vent line is a very old hose....I'm guessing clear nylon. If the rest of your sanitation and water hoses are close to 10 years old, you'd be smart to replace all of those too.

Replacing a vent line doesn't have be a difficult job...and you might want to find a shorter more direct route for it even that means relocating the vent thru-hull. If you opt to run it the same route, connect the new hose to the old hose using a male-male connector (cement the hoses onto it...tape won't hold and clamps will get caught) and pull the new hose through as you pull the old hose out. Use 5/8" flex PVC #148 white sanitation hose (it's also rate for water).

--Peggie

 

[jviss]

If the rest of your sanitation and water hoses are close to 10 years old, you'd be smart to replace all of those too.

(It's always scary to disagree with Peggy, she's such an expert. I do so at my own peril. )
I think that depends, Peggy. My boat uses the equivalent of Pex for the water plumbing, and just as you wouldn't pull it out of your house and replace it every 10 years, you wouldn't do so in a boat, either. It should last decades and decades. Doing this, replacing all the water plumbing on a 38' boat with one head, a galley, hot and cold water, stern shower, washdown, etc., would cost thousands and take many, many hours, unnecessarily.

If you have that reinforced, polyester, PVC hose stuck on barbs with hose clamps (which I hate!), I still see no reason to replace unless you removed an old hose for some reason. It does become hard with age, it seems. But I don't see why you'd do a rip-out according to the calendar.

Sewage hose - yes, agreed, I get that!

 

[Peggie Hall HeadMistress]

My boat uses the equivalent of Pex for the water plumbing

Does that include tank fill and vent line hose? Neither of which are fresh water "plumbing" btw.

If you have that reinforced, polyester, PVC hose stuck on barbs with hose clamps (which I hate!), I still see no reason to replace unless you removed an old hose for some reason. It does become hard with age, it seems. But I don't see why you'd do a rip-out according to the calendar.

No one is suggesting a rip-out according to the calendar. 10 years is a rule of thumb. The average working life of any hose is +/- 10 years. That's because the rubber and plastecisers in all flex PVC, nylon and rubber hoses dry out over time, causing hoses to become hard, brittle and prone to cracking and/or splitting as Tim's vent line did...which is the last thing you want to happen to any hose that's connected to your engine, exhaust, any below-waterline thru-hull or any part of your sanitation system, When that's happened it's time to replace it. If your fresh water plumbing is PEX or a similar material that has a much longer lifespan, that's one thing. But the fresh water plumbing on most production boats is the cheapest clear nylon water hose the builder could find. Is a failure likely to sink a boat? No. But builders also use the cheapest sanitation hose available. Fortunately it almost always starts to stink before it gets old enough to crack and split. But not always. So use the calendar as a guide but you still need to pay attention to everything on a boat and replace when indicated?

Ok?

--Peggie

 

[jviss]

Oh, yes, I get it Peggy. The fill lines on my tanks I'm not sure; the vents are el-cheapo, clear vinyl tube that I had to re-route. But it's in OK shape after 20 years. Fortunately, Tartan did a lot of the plumbing as you would you house, high quality.

The previous owner replace the sanitation hoses in 2016. Praise the Lord! But, yes, I get the idea of replacing those.

So, yes, I agree.

 

[Peggie Hall HeadMistress]

the vents are el-cheapo, clear vinyl tube that I had to re-route. But it's in OK shape after 20 years

Tartans are high quality boats. But if those vent lines were still in ok shape, your water tank vent line wouldn't have split.

Just sayin'...

--Peggie

 

[jviss]

Tartans are high quality boats. But if those vent lines were still in ok shape, your water tank vent line wouldn't have split.

Just sayin'...

--Peggie

It wasn't me with the split vent line, it was @ttibbits

 

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