holding tank vent hose

[richk]

I'm replacing my holding tank vent hose. The pic in this post shows the tank end and the pic in my next one will show the hull end. I don't want to remove the old hose until I understand a few things like What kind of hose is it? The fittings on both ends seem to have integral, white caps on them. Do I buy hose with these fitting attached? Whats up with this?I'm also concerned about how to remove the hose. The tank end is connected to a grey fitting and the hull to a black one. Do I just pull the hose off and risk breaking the fittings? Do the hose ends just screw off? Do I remove the fittings?Rich in Annapolis

 

[gfrazzle]

Head Vent

Looks like someone replaced the original with larger diameter hose by splicing onto the original hose ends, possibly because they didn't have the original size replacement or to use larger hose to improve venting ( will still be restricted by the hole diameter of the end fittings).If it were my boat, I would cut the old hose off at the tank/ hull fitting (the white hose under the clamp)and replace with new hose of the correct diameter- I think mine is 5/8 inch ID. Carefully cut the hose end lengthwise and it should come loose easily. Be careful not to cut into the fittings. Use either the clear braided or the white hose available at any marine outlet- just make sure it is the correct size- take the old end with you.

 

[Karl]

Looks like the original

I've owned two boats that have had hoses similar to the ones in the pictures. Hunter ordered flex hoses to size, and then had smooth ends fitted onto either end of the flex hose. My only guess is that the smooth ends hold a clamp better. They never caused me any trouble, and they were easy to remove. They just came off like any other hose, sometimes with a twist if the hose is stuck to free them. The bigger problem was always getting to the tank or through hull. I simply replaced the vent hose with a smooth sanitation hose.

 

[Peggie Hall HeadMistress]

What you have is...

Corrugated hose, connected to the tank fitting and the thru-hull using "cuffs," which no one in the marine industry has used for at least 20 years. So I suspect it was installed by someone who is clueless about the standards for marine plumbing. It needs to be replaced with smooth walled sanitation hose...which, btw, doesn't require any cuffs. You don't say, nor do your photos give a clue, what size your vent hose is. If you don't know, measure the INSIDE diameter. The so-called "standard" for all vent lines is 5/8", but only because that's also the standard size for fuel and water tank vents...and was adopted for holding tanks too because it allows boat builders to use the same size fittings and thru-hulls for all tankage, which saves 'em money but doesn't allow for the fact that wast--unlike fuel and water--needs to managed, not just held in a tank. Your photos don't provide any clude to the size of your vent line...but unless it's at least 1" ID (inner diameter), I advise some mods to the tank and thru-hull that'll allow you to increase it to that size.For a more detailed explanation of the reason WHY a larger vent helps to eliminate odor, I suggest you check out the link below..after you've searched all the archives for as much info as possible for "holding tank odor"...what REALLY causes it and how to maintain a tank to prevent it.