Broken thru hull vent?

[billybee41]

I have a 1994 Hunter 29.5 with a broken thru hull vent(I think it is a vent). enclosed are a few pics. It is located on the port side near the stern. the outside part broke off and is on the bottom. I noticed it was broken as I was leaving the boat and took the inside part off to get measurements to order the part and did not trace where the hose went. I am assuming it goes to either the holding tank or the fuel tank. The boat is 1 1/2 hours away and I was hoping to have the part when I go back. I have talked with Hunter and they are having a hard time finding one that fits the hole in the hull. The measurements in the pics are larger than all the fittings I have been able to find. The part no. in the owner's manual is PL0520 but I have not been able to find that number. The fitting next to it has a 90 degree fitting on the inside of the hull but this one is straight. Does anyone have a part no. and does the outside look like the other vent?

 

[Justin_NSA]

I can't help. I changed my bilge thru-hull from a straight fitting to a 90 degree. Without known part numbers the ODs and IDs can get confusing. Measure it when you can and post the dimensions. i.e. hull hole size and hose end size. Good Luck. Someone will know what to do.
Meantime, why is that chrome vent mounted sideways? The hood is supposed to shed water. This one looks like a water scoop.

 

[Jackdaw]

Many owners will increase the size of their head vent to promote good aeration. So maybe non-standard for Hunter. That would also explain the somewhat unsightly mix of materials used next to each other.

 

[Harlan]

Here you go:
http://www.defender.com/product.jsp?path=-1&id=3055723

 

[Dave Groshong]

Or you could purchase them here as well:

http://shop.hunterowners.com/prod.php?12729
http://shop.hunterowners.com/prod.php?12799
http://shop.hunterowners.com/hp/part.php?m=36&c=8&p=53350
http://shop.hunterowners.com/hp/part.php?m=36&c=13&p=53242

 

[whatfiero]

Yea I hope the other vent isn't for the fuel tank seems like water would migrate right in there

 

[Peggie Hall HeadMistress]

"Vent" thru-hulls are all 5/8" and designed to prevent sea water from contaminating fuel and water. Boat builders just use the same ones on all tanks, but they're horrible choice for the holding tank vent because they prevent the air exchange with the gasses in the tank that's necessary to prevent odor...which is why a PO has obviously replaced his holding tank vent thru-hull with a 1" open "bulkhead" thru-hull, available from any marine retailer. Any material will do EXCEPT nylon...UV turns nylon into dust.

You might want to check out the link in my signature for more information about the reasons why a 1" open thru-hull helps prevent odor.

 

[billybee41]

I can't help. I changed my bilge thru-hull from a straight fitting to a 90 degree. Without known part numbers the ODs and IDs can get confusing. Measure it when you can and post the dimensions. i.e. hull hole size and hose end size. Good Luck. Someone will know what to do.
Meantime, why is that chrome vent mounted sideways? The hood is supposed to shed water. This one looks like a water scoop.

Yeah I will take measurements when I go back. It looks like a round thru hull looking at the picture of the outside of the hull, but that would allow for water to enter easily.

 

[Ralph Johnstone]

I am assuming it goes to either the holding tank or the fuel tank.

I'm 99% sure the missing fitting was installed by the PO (as I did to mine) when I added another holding tank vent line:

The aft fitting is a factory original location for a fuel tank vent. The factory install was a chrome plated brass vent which really looked bad after five years. I changed over to SS. Although it looks wide open, it has an 24" high loop to prevent sea water ingress. The holding tank vent (one of two holding tank vents) doesn't have a loop so as to allow for better air flow.

This is what I used for the new thru-hulls:

The advantage of using these is that they have an internal NPT thread which allows you to install a 90 deg. fitting and immediately turn upwards for the internal loop. The SS fittings (I've seen) are usually only straight and barbed for hose.

 

[billybee41]

That looks like it will work. Thanks a bunch!!!!

 

[billybee41]

The vent is to the rear

 

[Justin_NSA]

I need to replace my clog-prone hooded thru hull vents with something like that. As long as you have an internal loop, the hood is superfluous. Except for providing a nice place to nest.

 

[Peggie Hall HeadMistress]

Billy, have you traced the line from the hull to find out for certain whether it's on the water tank, fuel tank or the holding tank? If it's on the holding tank, it doesn't matter whether a little water splashes into it. A vent thru-hull with a loop or a screen in it--in fact, any "vent" thru-hull--will cause more problems than it solves...screens get clogged with dust and pollen and also corrode, the loop defeats the whole purpose of having a larger diameter vent line...whereas an open thru-hull not only provides the previously mentioned air flow/exchange, but it also lets you stick a hose nozzle up against it and backflush the vent line every time you wash the boat, preventing tank vent blockages.

 

[billybee41]

Billy, have you traced the line from the hull to find out for certain whether it's on the water tank, fuel tank or the holding tank? If it's on the holding tank, it doesn't matter whether a little water splashes into it. A vent thru-hull with a loop or a screen in it--in fact, any "vent" thru-hull--will cause more problems than it solves...screens get clogged with dust and pollen and also corrode, the loop defeats the whole purpose of having a larger diameter vent line...whereas an open thru-hull not only provides the previously mentioned air flow/exchange, but it also lets you stick a hose nozzle up against it and backflush the vent line every time you wash the boat, preventing tank vent blockages.

I looked back at all the pictures I have of the boat. It is amazing how many pics I had of the starboard side and practically none of the port side. I did find one when I buying the boat and it was hauled for a survey. It was an open thru-hull and I have one on the way. I had never thought about getting better air flow but it makes a lot of sense. Thanks everyone for all the help.