Trojan Boat Forum

I am trying to locate the holding tank vent and filter (if there is one) on my 11 meter Express. I have tried chemicals and pumping out the tank, adding water and pumping out several times, but the smell persists. There does not appear to be a leak as the smell goes away within a minute or so. It would be so great to have a schematic of the boats systems. Does such a thing exist?

There are many things that can cause a smell... The hoses can be permeated and need replacement. The vent can be plugged. I would not have a filter on the vent hose. The reason holding tanks smell is due to lack of oxygen in the tank and the filter can really limit the amount of fresh air that can get into the tank. Besides if you inadvertently overfill the tank, the filter will plug up. I am in the process of replacing my head system and am putting two 1" vents in the tank, one on each side so I will get adequate air flow through the tank. Our last boat had a terrible smelling tank and I installed a Groco Sweet Tank which pumps air into the tank continuously. In 2 hours the smell was gone forever. I never put chemicals in the tank again. To test your hoses, wet a clean rag with hot water and rub it on the hoses. If you have a smell on the rag, your hoses need replacing. If you have a sea water fill for your head, that can cause smells particularly in salt water boats from the dead organisms in the stagnant water in the intake hose. If you use the head regularly, this does not happen as much though. Peggie Hall is the guru of heads. She wrote a book about them. You might still be able to find it. I spoke to her at length in June about my new head system, but she is pretty much retired now I guess.

I agree with Comodave's statements.If the odour is apparent only after you flush then goes away, you may have a ruptured vent hose that's venting inside the hull. Follow and inspect the vent hose from the tank to the fitting. What kind of system do you have?

At least you don't get the odor until after you flush. Some have the problem before ... long before in some cases

That long before the flush unpleasant smell is probably a problem with early "Venting" of the human kind...

I have the Vacuflush system. I have not located the holding tank or vent for it. Anyone have experience on the 11 Meter Express model?

Although mine is the 10.8 express model, it might be the same. My holding tank is under the v-berth bed.

If you have a Vacuflush, along with checking the vent hose, check the pressure side of the circuit for a leak. That is anywhere from the pump to the tank.

Been having a similar experience recently, and as I have been spending MANY days and nights on the boat recently, I started to investigate. Found a few things...#1 my '79 Tricabin with vacuflush has no cartridge filter. I suppose the PO just found them too expensive and just ran the vent directly to a drain/vent above the waterline. Unfortunately this vent sits right beside the port side salon windows. If the windows are open when you flush it just floods the salon with an unpleasent odour. Whle I was investigating this issue I pulled up the floor boards and tightened every connection I could see. Some were loose, some not. My vacuflush now works as its supposed to and I shut the windows when flushing. That said, I understand the holding tank SHOULd be anerobic, so I'm going to re-install the cartride.

For a few bucks, you can get all you need to build your own made of readily available 1.5" abs pipe and fittings from HD. Add charcoal that you buy at an aquarium store. Put the charcoal in a nylon stocking and insert into the cylinder. The cylinder can have a glued nippled fitting at one end....the one used for dishwashers, at the other end you use the same but attached to a threaded fitting for changing the charcoal sock later.

Thanks for the tip!
That probably saves about $90.00 plush shipping costs. If I can figure out how to make the first fitting "one way" I think the holding tank will remain anerobic.

If you do a google search you will find a great YouTube on how to
make the vent cartridge. Very simple.

I have slight smell from my tank also. I was told to make sure the vent hose is dressed not to allow liquid to be trapped in a drupe in the hose. The trapped liquid will not allow the tank to breath. mine was laying in the bilge, so I tie wrapped it so it sloped to the thru hull. Not sure if the trapped liquid issue is a true issue, but it sounds like it makes sense.

Bob Giaier wrote:I have slight smell from my tank also. I was told to make sure the vent hose is dressed not to allow liquid to be trapped in a drupe in the hose. The trapped liquid will not allow the tank to breath. mine was laying in the bilge, so I tie wrapped it so it sloped to the thru hull. Not sure if the trapped liquid issue is a true issue, but it sounds like it makes sense.

Correct, the vent hose should be going up hill from the tank to the vent fitting to prevent a blockage in case the tank is overfilled. Creating a loop that extends above the hull vent fitting helps keep out any water that may get into the fitting from outside.

While we're on the subject, allowing more air into the tank is very helpful for odour control, agitating the effluent however by injecting air directly into it is the best way to increase oxygen levels http://www.discountmarinesupplies.com/G ... ystem.html

Another good accessory to have is a tank saver which prevents your tank from collapsing during a pumpout as it allows much more air into the tank during pumpouts than a 3/4" vent hose would http://www.ardemco.com/sealand-31325524 ... ief-valve/