Venting mods

[gfroch]

Hi all-

Another question on our "new to us" 1987 Catalina 30. We had a major deck re-hab job over the winter which removed much wet core, replaced with plastic honeycomb core and came out beautiful. The job required removal of the stanchions. What a pain!!! We're in the process of replacing. Here's the question: The venting through stanchions was, in my opinion and observation, inefficient. The old ones were clogged. I'd like to add good old fashioned vents thru the hull for water and holding tank as long as it's all torn apart. Has anyone done this?

Thank you!

-gf-

 

[Capt jgw]

Venting the tanks through the stanchions was a dumb idea.
The only vent fittings commonly seen are made for fuel tanks and have a metal spark arrester screen in them which you don't want in your waste tank vent. Over fill the tank once and a chunk of solid material will plug the vent. Use a regular through hull fitting there, it still can clog but not as easily.
If you vent the water tank overboard, you do want the screen to keep bugs out.
It's better to run the water tank vent hose to a high point inside the boat and terminate it there if you can. That will eliminate any chance of getting sea water in your tank. You have to be more careful when filling though, you can't just stick the hose in and walk away.

 

[RoyS]

Be certain that your fuel tank vent hose does not have any droops in it, especially at the tank end. If any fuel, or water for that matter, gets lodged in a droop you will forever have difficulty refueling.

 

[Peggie Hall HeadMistress]

Venting fuel and water tanks through small openings in the aft side of a rail stanchion actually makes sense because it keeps sea water out of the fuel and water tanks. But venting a waste tank into a rail stanchion is a horrible idea. So I'd rerouted the waste tank vent line to a proper thru-hull--NOT a "vent" thru-hull, nor anything with a screen in it...screens cause more waste tank problems than they solve..but an open bulkhead thru-hull--just below the toe rail. That type of thru-hull will allow you keep the vent open by sticking a hose nozzle up against it and back flushing the vent line every time you wash the boat. No need to worry about keeping sea water out of sewage, so no need for any arch in the line...keeping it as short and straight as possible will also help to prevent odor from occurring in the tank.

As for the fuel and water tank vents...vent into stanchions again if you like, or install "vent" thru-hulls. Whichever you choose, be sure to put high arches in those vent lines to keep any water that does get past the the thru-hull from getting to the tank.

 

[PineyWoods]

Venting the tanks through the stanchions was a dumb idea.
The only vent fittings commonly seen are made for fuel tanks and have a metal spark arrester screen in them which you don't want in your waste tank vent. Over fill the tank once and a chunk of solid material will plug the vent. Use a regular through hull fitting there, it still can clog but not as easily.
If you vent the water tank overboard, you do want the screen to keep bugs out.
It's better to run the water tank vent hose to a high point inside the boat and terminate it there if you can. That will eliminate any chance of getting sea water in your tank. You have to be more careful when filling though, you can't just stick the hose in and walk away.

I've owned, or sailed on a variety of cruising boats over the past fifty years and have NEVER seen one without a proper water tank vent/vents - all high hull, aft-facing or clamshell-protected, except the S&S Swan 41 with a spout into the galley sink for each of the three tanks. Sea water in the tanks with proper aft-facing vents? Not impossible I guess in a knockdown, but under way totally improbable.

Big surprise finding only a couple feet of vent tubing emptying into the lockers on my "new" '82 30. So I connected the vents of the two tanks through a T fitting and ran it up through the hanging locker, electing to vent it with an aft-facing screened stainless fitting through the deck just aft of the stanchion aft of the tank fills.

Pete

 

[Capt jgw]

They're are quite a few boats with the water tanks vented inside the hull. All or most Columbias were plumbed that way, and probably others as well. If the vent goes outside it can draw in water, aft facing or not. And it's one less hole in the boat. The only downside to venting inside is the chance of over filling and flooding the boat. On my Columbia 8.7 the end of the vent line was above the galley table and the first time I filled the tank and left it unattended it drenched everything on the table. I just didn't leave it unattended after that.

 

[PineyWoods]

Then I would say that both Columbia and Catalina were cheapskates in this regard!

Even my Erickson 25 of the same 70's ilk had a vent. I daresay that no higher end boats would threaten their well-crafted interiors and dry bilges with this oversight.
Pete

 

[Capt jgw]

It's more a safety concern not allowing your water to get contaminated. But these are not circumnavigators, doubtful anyone would be at sea long enough to die if they lost a tank.

 

[gfroch]

Thank you all for the advice. Thru-hull for sewage and vent for water it is. We aren't doing anything to fuel since that is vented through the transom. The new fittings will be MUCH easier to access. I agree (in my opinion) that venting to the stanchion was not a great idea.
By the way , we aren't real concerned about sea water in our freshwater tanks. The rail rarely goes in the water, we sail in fresh water, and in fact, we don't ever drink the water from the holding tanks.
Thank you for your help!
-gf-

 

[mortyd]

a little thing but fyi, the holding tank is where the waste from our head goes until you get rid of it. the fresh water ttanks are totally different from the holding tank.

 

[Capt jgw]

You see people using the word both ways. I prefer to say
"waste tank" to avoid confusion.

 

[gfroch]

You mean we're not supposed to drink from the holding tank!?!?!? No wonder that water tastes so bad!

Haha. Just kidding. Typo above. Thanks for pointing out.

Cheers...