My 15 gallon plastic holding tank current has about 1.5 gallons of water in it this season. There are two vent hoses coming off of the top of the tank to a "T" fitting and then one tube to a vent on the side of the boat. The outside vent is clear and I replaced the tube between the "T" fitting and the outside vent on the starboard side of the boat. I replaced all of the sanitation hoses with new Raritan hoses last year. There have never been any solids flushed during my 8 years of ownership. I noticed clear water in the new vent tube. The head flushes well. What is forcing water into the vent tube when the holding tank is almost empty?
Holding Tank Vent Question
- Thread starter StanleyJ
- Start date
Teeing two vent lines together to go to a single thru-hull prevents either one of them from accomplishing anything.
Holding tank vent lines should be short (ideally no longer than 5' but that can be hard to achieve depending on the location of the vent fitting on the hull) straight and rise no sharper than 45 degrees. Replacing the "vent" thru-hull with an open bulkhead fitting (the kind your bilge pumps use) eliminates the need for a second vent and also allows you to prevent vent blockages by putting a hose nozzle against it regularly to back flush vent line...anything that tries to set up housekeeping in it will get a water slide ride into the tank.
As for the source of the water in your tank...that's gonna require more conversation than is practical in open forum 'cuz I have questions that need answers before I can offer any solutions. If you'd like to pursue it, send me a PM.
--Peggie
Thanks Peggie and Greg!
I was back at my boat yesterday and rechecked the vent hose. I did wash my boat after replacing the vent tube so maybe the water got in the tube from washing but the outlet has a cover on it. I haven't buried a rail in the water in 25 years and do not wish to relive the experience. My Oday 272LE manual does show (2) vent tubes (one at the top front of the tank and one at the top rear) going to a T-fitting and one thru hull. I will try capping one tube off and changing the thru hull to an open one as Peggy suggested.
I was back at my boat yesterday and rechecked the vent hose. I did wash my boat after replacing the vent tube so maybe the water got in the tube from washing but the outlet has a cover on it. I haven't buried a rail in the water in 25 years and do not wish to relive the experience. My Oday 272LE manual does show (2) vent tubes (one at the top front of the tank and one at the top rear) going to a T-fitting and one thru hull. I will try capping one tube off and changing the thru hull to an open one as Peggy suggested.
