Holding Tank Question

[jmain]

Well, I must have been naughty this year, because Santa left me some sewage in the bilge of our Marlin 30 (1996). I may have multiple problems, so bear with me...
The tank level indicator for the holding tank is clearly not working. It says it is 1/2 full, but before I emptied it last time, it overflowed (but, I didn't know it at the time).

Question #1: What is SUPPOSED to happen, when the holding tank is full? Is it supposed to go out the vent? The overboard discharge? In the bilge? Not flush?

Mine apparently came out in the bilge from under the head. You can't see all of the hose, so I am wondering if the hose is ruptured, or if there is an overflow valve that is supposed to be there. All of the hose that is visible above the floor and under the floor going to the holding tank looks fine.

There is no evidence of water/liquid/other *stuff* in the bilge since I cleaned it out with bleach. However, using the boat this weekend has the smell coming back. It doesn't smell like pee or other things that go down a marine head. It almost smells like something dead. When we got the boat, we found evidence of rodent activity in the forward rope locker and in the starboard side panel in the aft berth. It appeared to be years old and there is no new evidence of activity, but I am wondering if one of the dead critters is still in the bilge and is getting wet from either the head or the windshield washer knob leak (that is a different problem).

The smell is definitely coming from under the head or forward bilge, not the holding tank.

Question #2: Is there anyway to get under the floor of the head? I sure can't see a way to get to it.

Thanks in advance!

 

[DennisG01]

There are multiple types of head systems so the answer could depend on what specific style you have.

If you have a sensor that when it trips "full" (which you probably have... but is gunked up), in some systems that prevents flushing.

Nothing will go out the vent - that is the highest thing in the system. Nothing should go out the oveboard discharge automatically... that would be bad for the environment. What will happen, though, is that the... let's call it "fluid"... will backup in the system and leak out of the first place it can - and then it can travel who knows where so fully cleaning it out becomes a big problem.

 

[seasick]

If waste water accumulated in the bilge area under the head, you have a leak in or near the toilet fixture. Waste water should not under most scenarios run into the bilge. So you have a leak somewhere in the fixture plumbing or in the sanitary hose.

About your other questions:
A full holding tank will not stop the toilet from operating but will result in spillage somewhere. I am not familiar with the vent in your holding tank but it is probably on the outside of the hull. There may be a float of some sort that should block the vent when the tank is full but I am not sure.
If the boat is operated or stored in a region that gets below freezing weather, it should be drained and winterized before the temps drop. If not, things can freeze and break pumps, fittings, hoses or the toilet itself
Also check the age of the sanitary hoses when you check the system for leaks. Sanitary hoses degrade over time and can allow odors to permeate through the hose itself. Right now that isn't your problem

 

[jmain]

Thanks @DennisG01. I am assuming that the holding tank is original. The plate on top of the tank itself is illegible. The monitor is a Groco GM-50, which I assume is also original.
I am thinking I will put on 5 Covid masks and take the top off the tank, when we get home. Maybe, if the float is stuck and it prevents flushing, that is the short term fix until I can find the leak. Now that you mention it, when we first got it, the head wouldn’t flush out of the blue. I attributed it to the house batteries being bad, but maybe it was actually working as designed. I don’t remember when we got pumped out relative to that happening.
Thanks for the help. I appreciate it!

 

[jmain]

If waste water accumulated in the bilge area under the head, you have a leak in or near the toilet fixture. Waste water should not under most scenarios run into the bilge. So you have a leak somewhere in the fixture plumbing or in the sanitary hose.

About your other questions:
A full holding tank will not stop the toilet from operating but will result in spillage somewhere. I am not familiar with the vent in your holding tank but it is probably on the outside of the hull. There may be a float of some sort that should block the vent when the tank is full but I am not sure.
If the boat is operated or stored in a region that gets below freezing weather, it should be drained and winterized before the temps drop. If not, things can freeze and break pumps, fittings, hoses or the toilet itself
Also check the age of the sanitary hoses when you check the system for leaks. Sanitary hoses degrade over time and can allow odors to permeate through the hose itself. Right now that isn't your problem

If waste water accumulated in the bilge area under the head, you have a leak in or near the toilet fixture. Waste water should not under most scenarios run into the bilge. So you have a leak somewhere in the fixture plumbing or in the sanitary hose.

About your other questions:
A full holding tank will not stop the toilet from operating but will result in spillage somewhere. I am not familiar with the vent in your holding tank but it is probably on the outside of the hull. There may be a float of some sort that should block the vent when the tank is full but I am not sure.
If the boat is operated or stored in a region that gets below freezing weather, it should be drained and winterized before the temps drop. If not, things can freeze and break pumps, fittings, hoses or the toilet itself
Also check the age of the sanitary hoses when you check the system for leaks. Sanitary hoses degrade over time and can allow odors to permeate through the hose itself. Right now that isn't your problem

Thanks, @seasick.
as far as I know, the boat was always in southwest FL, so freezing shouldn’t be the problem, but I’ll check for broken stuff, as I take it apart.
To your point about the hoses, I think I’ll just replace all of them, since they appear to be original. That is a cheap fix, if that is the source of the smell, and will prevent me from having to clean the bilge again!
Thanks for the suggestion. I appreciate it!

 

[DennisG01]

You're welcome, J. Just an FYI, what I meant by "head systems" is that there are different styles/setups. PortaPotti with macerator... manual flush setups... Vacuflush... etc, etc.

As far as I'm aware (and I know for a fact regarding Vacuflush) there is no one-way valve on a vent. There's really no need for it since it's the highest thing in the system, by design.

 

[glacierbaze]

I’d start by doing a complete pump out, And flush with as much freshwater as whoever is doing the pump out will let me get away with it, to limit what, and how much you might spill during the repair.
I can’t think of a marine head with an overflow, unless it flows back through the toilet. They are pretty much a closed system, until you open a discharge port, which ever one that may be.

 

[jmain]

I’d start by doing a complete pump out, And flush with as much freshwater as whoever is doing the pump out will let me get away with it, to limit what, and how much you might spill during the repair.
I can’t think of a marine head with an overflow, unless it flows back through the toilet. They are pretty much a closed system, until you open a discharge port, which ever one that may be.

Thanks, @glacierbaze, that is the plan. Flush it completely a couple of times with bleach. The guys at the marina are very accommodating, so that shouldn’t be a problem, as long as they aren’t really busy.

 

[Legend]

When my electric head is full, it will still allow you to run the bowl flush pump, it just will not clear the bowl since there is no more room for it to go down to the holding tank. This past summer I replace my tank monitor with a SCAD tank monitor. It is much more accurate than the original monitor and was an easy install as it is an external monitor.

 

[seasick]

When my electric head is full, it will still allow you to run the bowl flush pump, it just will not clear the bowl since there is no more room for it to go down to the holding tank. This past summer I replace my tank monitor with a SCAD tank monitor. It is much more accurate than the original monitor and was an easy install as it is an external monitor.

That assumes that the plumbing doesn't leak and the tank vent seals the vent when the tank is full

 

[Fishtales]

How to ruin your Christmas week. Good luck with the clean up.

 

[Meanwhile]

.
I am thinking I will put on 5 Covid masks and take the top off the tank

Vicks Vapo Rub on the upper lip for the win.

 

[Byram]

The vent hose degrades over time . It becomes permeable and gets sticky. That could be the smell issue .It doesnt smell like crap but funky. You didnt say what kind of toilet you have. electric etc. Cleanup as best you can and replace all hoses from toilet to tank. This past summer I rebuilt my raritan electric head and replaced every hose and put in a larger holding tank in my other boat. My wife said she smelled something. I said "yes dear"