Head holding tank vent line - 1981 E37 Plan 'B'

[wrbanwal]

I want the marina to fix was replacing the vent line. It stinks. and its old and I think there might be debris in the line.

The marina guy tells me and I agree it will be very difficult to get to it. And it runs aft (down hill) then up to the thru hull.

They recommend we run a new vent forward toward the anchor locker then out the front.

My main question for everyone - Does it seem like the right thing to do? Putting a vent line on the bow of the boat?

has anyone had experience replacing the vent line in their holding tank?

thanks

[sea_hunter]

Endeavour vents are easily accessible. Try a wet dry vacuum inside then out side with somebody holding a hose on the vent. Sometimes it takes some time but you can get it cleaned out without replacing.

[SlowButSteady]

If the vent line actually runs down and then up it essentially forms a "trap". Any moisture inside will pool at the lowest point and prevent air from getting through, hence the stink. I would re-route the line so that it has no low points. I would also install a second vent in the tank. A single vent will only act to equalize the pressure between the tank and the atmosphere, with little or no circulation. This results the tank becoming anaerobic and stinking. Having two vent lines, with their exterior fittings located as far apart as practical (for a slight pressure differential), will allow for exchange between the tank and atmosphere, and help to keep the tank aerobic (and MUCH less stinky).

[wrbanwal]

Originally Posted by SlowButSteady

If the vent line actually runs down and then up it essentially forms a "trap". Any moisture inside will pool at the lowest point and prevent air from getting through, hence the stink. I would re-route the line so that it has no low points. I would also install a second vent in the tank. A single vent will only act to equalize the pressure between the tank and the atmosphere, with little or no circulation. This results the tank becoming anaerobic and stinking. Having two vent lines, with their exterior fittings located as far apart as practical (for a slight pressure differential), will allow for exchange between the tank and atmosphere, and help to keep the tank aerobic (and MUCH less stinky).

I like the idea of two vent lines.

with the holding tank in the v-berth, my only real option to go up is to go forward. I just wonder what effect that will have those few times I bury the nose in the water. Is that going to fill my undersized 12gal holding tank?

[SlowButSteady]

Originally Posted by wrbanwal

I like the idea of two vent lines.

with the holding tank in the v-berth, my only real option to go up is to go forward. I just wonder what effect that will have those few times I bury the nose in the water. Is that going to fill my undersized 12gal holding tank?

Put a little clamshell cowl on it, with the opening facing aft and down a bit. If you bury the bow you should be moving forward fast enough to keep water from overcoming the Venturi effect.

[wrbanwal]

ugh

vent lines done.

still stinks

[SlowButSteady]

Well, you're probably never going to get it to smell like a bouquet of roses. You'll particularly have a hard time getting rid of the stink if the tank has been anaerobic for a long time, as the hydrogen sulfide produced under anaerobic conditions will permeate any plastic. However, over time the smell should get better.