Holding tank hilarity

Oct 9, 2008
1,739
Bristol 29.9 Dana Point
Without long details:
Holding tank was pressurizing.
Looked up inside vent on the hullside, appeared clogged. Also kink in the hose on vent backside.
Replaced vent, relieved hose.
Still pressurizing.
Removed vent hose from tank. Oops, it was full. (#1)
I check it with a flashlight but apparently the line was a false one from previous contents.
Realized that pump outs had not been complete recently, due to clogged vent. Therefore drastically miscalculated capacity.
The old 2 burnt light bulbs in the Christmas tree syndrome: Clogged vent = bad pump outs. Bad pump outs = clogged vent (at tank).
 
Dec 2, 1997
8,709
- - LIttle Rock
Replaced vent, relieved hose.
Still pressurizing. Removed vent hose from tank. Oops, it was full. (#1)
I check it with a flashlight but apparently the line was a false one from previous contents.
What does "replaced vent, relieved hose" mean??? And I have no idea what this means: ...but apparently the line was a false one from previous contents.
Anyone who removes a hose from a holding tank without first opening the pumpout cap (and it's a good idea to make sure you're UPwind of the pumpout fitting with a hose at the ready when you do) to relieve any pressure in the system can expect a bilge full of tank contents. Even if only urine went into the tank, urine stinks too. So it's likely to create an odor issue if you don't THOROUGHLY clean up the spill and then treat every surface, nook and cranny in that area with PureAyre.

If you haven't already done so, this would be a good time to replace the vent thru-hull with an open bulkhead thru-hull that you put a hose nozzle against and backflush the vent line every time you wash the boat and/or pumpout...thus, preventing any future blocked vents.
--Peggie
"If you can't explain it to a six year old, you don't completely understand it yourself." --Albert Einstein
 
Oct 9, 2008
1,739
Bristol 29.9 Dana Point
What does "replaced vent, relieved hose" mean??? And I have no idea what this means: ...but apparently the line was a false one from previous contents.
Anyone who removes a hose from a holding tank without first opening the pumpout cap (and it's a good idea to make sure you're UPwind of the pumpout fitting with a hose at the ready when you do) to relieve any pressure in the system can expect a bilge full of tank contents. Even if only urine went into the tank, urine stinks too. So it's likely to create an odor issue if you don't THOROUGHLY clean up the spill and then treat every surface, nook and cranny in that area with PureAyre.

If you haven't already done so, this would be a good time to replace the vent thru-hull with an open bulkhead thru-hull that you put a hose nozzle against and backflush the vent line every time you wash the boat and/or pumpout...thus, preventing any future blocked vents.
--Peggie
"If you can't explain it to a six year old, you don't completely understand it yourself." --Albert Einstein
Replaced the vent at the hullside. Relieved stress on the hose to eliminate the kink.
No mess inside. Had towels under when rem hose from tank. Put hose back on immediate.
Good advice re fill cap. Although wouldn't have helped in my case. Liquid was draining out the vent at tank and down from vent hose. Not pressurized when I did that work. Long details....
 
Nov 6, 2006
9,885
Hunter 34 Mandeville Louisiana
OOOFFF good to hear that ya have that one heading your way, Skipper!
 
Oct 1, 2007
1,857
Boston Whaler Super Sport Pt. Judith
Without long details:
Holding tank was pressurizing.
Looked up inside vent on the hullside, appeared clogged. Also kink in the hose on vent backside.
Replaced vent, relieved hose.
Still pressurizing.
Removed vent hose from tank. Oops, it was full. (#1)
I check it with a flashlight but apparently the line was a false one from previous contents.
Realized that pump outs had not been complete recently, due to clogged vent. Therefore drastically miscalculated capacity.
The old 2 burnt light bulbs in the Christmas tree syndrome: Clogged vent = bad pump outs. Bad pump outs = clogged vent (at tank).
Didn't she lose?
 
Oct 9, 2008
1,739
Bristol 29.9 Dana Point
And I have no idea what this means: ...but apparently the line was a false one from previous contents.
I check the tank level with a flashlight from the outside. It's plastic, sort of transparent but not really. However, the level-line inside the tank was residue from when the tank had sat with 2 in it for awhile. So I misread the level, not being able to clearly see inside. Need a brighter flashlight.
Long details....

This post was not a question, just me laughing at my luck and noting a possible double cause for tank pressurizing. In case others can use when addressing similar.
 
Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
... replace the vent thru-hull with an open bulkhead thru-hull that you put a hose nozzle against ...
I'm sure Peggie meant a "mushroom"-type thruhull, which is what I did. I think my vent hose is an inch or more. The hose sprayer fits into the thru-hull nicely. When I know the pumpout boat is on the way, I take the deck pumpout cap off, spray water into the vent thruhull until I see the poo rising in the pumpout deck fitting. Vent's clear!
 
Mar 29, 2017
576
Hunter 30t 9805 littlecreek
When my vent hose was clogged the pump out would just suck air out head and I'd get a great clean pump out
 
Dec 2, 1997
8,709
- - LIttle Rock
I'm sure Peggie meant a "mushroom"-type thruhull,
I meant "bulkhead." However, its real name is actually "bulkhead fitting"... it's been given the nickname "mushroom" thru-hull because a)it's a thru-hull and b) it looks like mushroom.

When my vent hose was clogged the pump out would just suck air out head
When the toilet is the pumpout's only source of air, pumping/flushing will pressurize the tank. A pressurized tank will relieve the pressure wherever it can, which is also likely to be the toilet. You don't want to be bending over the bowl pumping the toilet when that happens.

If the pumpout can easily pull all the air it needs through the toilet, it also means that the joker valve is in desperate need of replacement...that the slit has become a hole that's caused your toilet lose about half its pumping efficiency. Find my article "joker valve 101" in the archives (also in my book...see link in my signature) for the complete explanation.

--Peggie
"If you can't explain it to a six year old, you don't completely understand it yourself." --Albert Einstein
 
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Oct 26, 2008
6,048
Catalina 320 Barnegat, NJ
I take the deck pumpout cap off, spray water into the vent thruhull until I see the poo rising in the pumpout deck fitting. Vent's clear!
I'm left wondering if your vent fitting is higher than your deck fitting! If not, don't you have to be careful when spraying that you don't cause a back up in the vent? Also, either your vent fitting is right next to your deck fitting or you need 2 people and accurate communication to perform this trick, no? Mine are about 10' apart (at least) and the vent fitting is slightly lower, so I can't see how this works so well. ;) Besides, I don't generally take a close look inside the pump out hose and the slight bend near the fitting makes direct observation way too close and personal for my comfort! :(
 
Oct 26, 2008
6,048
Catalina 320 Barnegat, NJ
BTW, my vent termination is actually inside the anchor locker at the bow. I'm wondering if that is not such a good location. I generally don't fill the anchor locker with water to clean/flush it out, but it is a concern.
 
Dec 2, 1997
8,709
- - LIttle Rock
BTW, my vent termination is actually inside the anchor locker at the bow. I'm wondering if that is not such a good location
It's not only not a good location, it's actually vented illegally. USCG regs require that all waste tanks be vented to the outside of the boat because toilet waste and gray water can generate methane and methane is is flammable. This would create a great excuse for you to upgrade your vent line to 1" (easy to do, thanks to a li'l gizmo called the Uniseal UNISEAL). Install a 1" open thru-hull about a foot below the toe rail a couple of feet aft of the stem, and you'll have a tank that's guaranteed never to stink.
--Peggie
"If you can't explain it to a six year old, you don't completely understand it yourself." --Albert Einstein
 
Dec 2, 1997
8,709
- - LIttle Rock
When I know the pumpout boat is on the way, I take the deck pumpout cap off, spray water into the vent thruhull until I see the poo rising in the pumpout deck fitting. Vent's clear!
You're seriously over-producing something that's really very simple. All you need to do--without removing the pumpout cap-- is put a hose nozzle against the thru-hull and give it a blast of water...I can't imagine it needing more than a pint ...every time you wash the boat and/or pump out...enough to give anything that's tried to set up housekeeping in the vent line a water slide ride into the tank.

--Peggie
"If you can't explain it to a six year old, you don't completely understand it yourself." --Albert Einstein
 
Oct 26, 2008
6,048
Catalina 320 Barnegat, NJ
It's not only not a good location, it's actually vented illegally. USCG regs require that all waste tanks be vented to the outside of the boat because toilet waste and gray water can generate methane and methane is is flammable. This would create a great excuse for you to upgrade your vent line to 1" (easy to do, thanks to a li'l gizmo called the Uniseal UNISEAL). Install a 1" open thru-hull about a foot below the toe rail a couple of feet aft of the stem, and you'll have a tank that's guaranteed never to stink.
--Peggie
"If you can't explain it to a six year old, you don't completely understand it yourself." --Albert Einstein
I'm wondering if the anchor locker isn't technically outside the boat. It is simply a shallow well in the bow that has a cover. There is a drain to a thru hole on the side of the bow (above waterline) and the cover has a notch at the front edge that is large enough to pass a nylon rode. There is no opening to the interior below deck. That said, the fitting is for 5/8" tube and it wouldn't hurt to add a thru hull on the side to pass a 1" vent. That would require a new fitting on the 10 gallon tank as well.
 
Dec 2, 1997
8,709
- - LIttle Rock
A well with a cover on it is an enclosed space IN the boat where gasses from the tank can be contained. So it's definitely INside the boat. Same would be true of a lazerette.
That would require a new fitting on the 10 gallon tank as well.
The Uniseal makes that easy to do.

--Peggie