What happens if holding tank is overfilled?

[Aquah0lic]

My tank has no gauge so I have no idea how much is in there, how long it will go or how much I pump out. How do you get around this and what happens if you wait too long?

[nodee]

How about this:
SCADTechnologies, Sensibulb LED

Pretty simple installation. Cheers!

[cal40john]

If your tank is plastic and you can see a side, shine a flashlight through it to determine depth of liquid. If not you're stuck having to put a gage in it, unless you want to empty early and often. There are both internal and external gages available. If you overfill it, stuff will come out the vent letting you know the tank is full. This method is a problem because it is illegal, it is messy, you can clog your vent line, and you can overpressurize your tank potentially causing some fitting to fail.
Actually I believe that having some method to determine the level of liquid in the holding tank is in the law.

John

[Aquah0lic]

my tank is buried somewhere under my v berth. I haven't seen it, maybe there is a gauge on it.

[witzgall]

In our case, when it is overfilled, then pressure forces effluent out of the hoses in into the bilge. Not pleasant. It is stainless, so we cannot see the level.

We have a Lavac head, which as far as pumps go I bet it is fairly strong. We are now trained to know the signs for it being full, in our case, the pumping gets harder.

How they thought a 6 gallon tank would be enough I'll never know...

Chris

Originally Posted by Aquah0lic

My tank has no gauge so I have no idea how much is in there, how long it will go or how much I pump out. How do you get around this and what happens if you wait too long?

[JHJensen]

Cal40John is correct about the law.

Sec. 159.83 Level indicator.
Each sewage retention device must have a means of indicating when

the device is more than ¾ full by volume.

Legal issues aside, knowing when your holding tank is full and how to manage it is just part of good seamanship and effective management of your vessel.

Aquaholic is asking a great quesiton about this often taken for granted system. Knowing how long it takes to fill it etc.

In looking at your holding tank... make sure you look a the entire system as well: the head, intake and discharge fittings and piping, flush water source ( salt or fresh), antisiphon and so on. If you vessel is older and you have never really paid attention to this system so essential for human comfort This winter is a good time to take a look and really understand the system. Maybe plan some upgrade or take care of some long overdue maintenance.....your crew will thank you in long run.

There are many electronic monitors which can be used to monitor all of your vessel's tankage and other systems.

The Blue Sea Systems VSM 722 caught my eye this morning in their newsletter. Vessel Systems Monitor - Blue Sea Systems

There is also the old proven Tank-Tender system The Tank Tender - by Hart Systems, Inc.

When I do a maintenance assesment on a vessel, the sanitation systems tell me a great deal about how she is cared for and used and how knowledgable the owner is.

As an owner when you have guests on your vessel, telling and showing them how this crtical system works should come right after you go through your safety check list. I alway remind guests to ask for a refresher if they don't remember how it works.... really avoids problems in the long run.

Have a great day

John
ABYC Master Technician
Marine Educator and Surveyor

[nautical62]

What happens if a holding tank is overfiled:

Bad things happen. Very, very bad things. Don't over fill it.

[Christian Van H]

What happens if your holding tank is overfilled? Boats wont anchor around ya... Often, the effluent shoots out of whatever orifice it can when ya continue to pump the head. Most likely the tank vent. Oh, and it smells like hell!

[Cormorant]

Defender has the best price on the TankWatch 1 Holding Tank Alert System, at $60.

Tankwatch 1 Alert System

Or do a little searching around for "tank float switch" -- though it has been said on other threads that moving parts in a waste tank are likely to get gummed up eventually.