LOOP IN VENT LINE

S

Sailboattraitor

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Apr 5, 2005
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16877
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38
I was crawling around in the engine compartment yesterday and noticed that the vent line from my holding tank has a full loop in the line just before it attaches to the vent hardware leading to the outside of the boat. Do I really need a loop in the vent line or can I just rune the vent line directly from the holding tank to the vent hardware? Thanks in advance for any assistance.
 
"Do I really need a loop in the vent line"

Yes.

( unasked, yet, question ) Why? Without the loop, you can fill the H/Tw/ seawater ( even, potentially, you can sink the boat). When the vessel heels over, the hull vent might go below the waterline. If there is no loop, then the seawater can freely enter the H/T. The loop delays this activity till you are heeled much farther over. In short, keep the loop. ( fwiw: I also think it is "code", ABYC etc )
 
I agree that keeping the loop on the holding tank vent hose would be wise on a heeled-over sailboat, but what about on a 2002 Ciera 2655? The vent hardware on the hull is high above the waterline and if I heeled-over that much on my powerboat, I would have greater problems than water in the holding tank. ;-)
 
You asked, you got the answer. Yes, you need the loop. Also, it keeps you in compliance with the various standards organizations. Stink pots can ( and do ) heel as much as many blowboats, just not as often. In the event you heel heavily, you do not want an additional issue of flooding the H/T and also possibly ( rarely ) flooding the compartments as the heads back up.

You need the loop.
 
I disagree; with a full loop in the holding tank vent line, if any water comes in while the boat is heeled, or while bouncing around in the waves, it will collect in the loop and the tank won't vent any longer. The vent line should run as horizontal as possible, and should exit the boat high on the side of the hull, up near the toe rail - without a loop in the line.
 
+1 for Vic. Even a gas 'burp' while filling up will block any venting of the tank. The straightest vertical shot from tank to hull vent fitting.
 
How would the tank be able to freely vent with a loop in the line?
1+ for Vic.
Bill
 
quote:
Originally posted by Vic Willman

I disagree; with a full loop in the holding tank vent line, if any water comes in while the boat is heeled, or while bouncing around in the waves, it will collect in the loop and the tank won't vent any longer. The vent line should run as horizontal as possible, and should exit the boat high on the side of the hull, up near the toe rail - without a loop in the line.

Click to expand...

I'm going with Vic on this one. Not only is it his field of expertise, it makes sense.

For those who feel not having a loop in the holding tank vent line could cause the holding tank to fill and sink the boat - what happens when you fill the tank with sewage? Nothing except that it's full. If your holding tank is so large that filling it could sink the boat, you have a design problem tha needs to be addressed.

BTW: When I replaced my hoses, I removed the loop in mine. It's not ideal as Vic describes, but it's better than it was.
 
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