H-34 Head Vent

[YVRguy]

I have a 1986 H34 and it seems my head vent is clogged. That said, I'm not sure which of the thru hulls is the head vent. I don't want to go blasting the hose in the wrong place so I'm hoping for some guidance on which one it is. Anyone?? Thanks in advance...

 

[Mike Oldak]

I believe that the holding tank thru hull is located behind the head. The hose from the holding tank vent goes forward under the wall then up the hull behind the head. I just replaced my entire system and the vent from the holding tank may be clogged not the hose.

Since we never go out of US waters, I sealed the outlet thru hull and removed all the over board plumbing.

Also, the smell maybe coming from the false bilge problem discussed on this forum.

 

[Claude L.-Auger]

Of the 2 vents you see on the hull near the head, one is the head vent and the other one is the shower sump outlet. So you could try and see where it goes, you will not do any damage. Just don't blast, insert the hose nozzle and skirt water in. If you get water in the shower sump, the pump will take care of it and you'll know it's the other vent you need to clean. Good luck

 

[Peggie Hall HeadMistress]

Trace the vent line from the tank to the hull...that's where the vent thru-hull will be. It'll prob'ly be exactly like the water and fuel tank vent thru-hulls, which makes it hard to clean out by blasting it with a hose because they're designed to prevent sea water from contaminating the fuel and water via the vent. 99% of vent blockages occur in only two places: the vent thru-hull or the other end of the vent line--that end of the hose or the vent fitting on the tank.So scrape it out...use a screwdriver blade, ice pick--whatever works. If there's a screen, knock it out...screens cause more problems than they prevent. If that doesn't result in a spew out the vent, you'll need to relieve the pressure before removing the vent line from the tank to clean them out...so open the deck pumpout fitting VERY CAREFULLY with a hose at the ready. Be sure you're UPwind of it! Scrape out that end of the vent line and the vent fitting on the tank...replace the vent line. If there's a filter in the vent line, remove it...once a filter gets wet--which can happen when a tank is overfilled or even due to heeling--the charcoal swells and blocks the vent...one of the reasons why vent filters aren't recommended for use on most sailboats.
One you've found the thru-hull, this would be a great time to replace the vent thru-hull with one you CAN blast out--an open bulkhead or "mushroom" thru-hull that'll let you prevent blocked vents in the future by sticking a hose nozzle against it and backflushing the line every time you wash the boat and/or pumpout.
--Peggie

 

[Peggie Hall HeadMistress]

Claude, I think the vent will be a lot higher on the hull the sump drain thru-hull.
--Peggie

 

[kloudie1]

On my 85 model, the aftmost of the two mushroom fittings just under the toe rail is the holding tank vent. As Claude says, the forward one is the shower sump pump outlet. My vent
has plugged a couple of times at the tank outlet nipple; it’s actual opening is about 3/8 inch, too small, but that is what we have.

 

[Peggie Hall HeadMistress]

Replacing the vent thru-hull is a fairly easy job, Claude...that is, unless Hunter made access to it nearly impossible....but definitely worth the effort, even if they did.
--Peggie

 

[YVRguy]

Thanks all, for the very detailed answers. I have what I need now, and more. Unfortunately talking about fixing these problems is easier than actually fixing them. Here goes...

 

[markwbird]

There are a pair of through hulls just below the gunnel outside the head on the starboard side. I believe it’s the aft one.

 

[mnmpizza]

I found mine clogged on my H34 just last week. The telltale was a small backup of waste in the toilet. This never used to happen. Was able to open the clean out an back spray down the vent. Took a few attempts, but got it unclogged. Funky smell now gone!! Like others have mentioned, there is a pair of through hulls in the shower compartment — it’s the aft one (on my boat)