Holding Tank problems

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Squeaky

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Good afternoon:

I have a s/s holding tank which is emptied by gravity when the sea cock is opened. Under normal usage the toilet is emptied through the tank and out through a seacock and skin fitting.

There is no outlet on deck although there is a vent under the toe rail. This has been useful because I have been able to fit a foot pump into the vent hose and raise the internal pressure when the tank becomes blocked for what ever reason. Took a lot of nerve the first time as I expected the whole thing to blow back in my face - it takes an enormous amount of pressure sometimes to clear the blockage. I use a bicycle foot pump with the value fitting removed which lets me insert the pump hose into the vent pipe hose securing it with a jubilee click.

I can also empty the tank using a hand pump through the vent fitting if necessary - bucket and chuck it.

Having been in the water for over two years the pipes are now blocked and I cannot clear it with the foot pump nor can I by removing the exit hose between the tank and seacock - it had a good build up inside but that was easy to remove however the system still will not drain. This leads me to believe that the skin fitting and elbow have become blocked with barnacles or other nasties.

There is an inspection opening in the top of the tank - I wonder if anyone has tried inserting one of the length of wire used domestically for clearing sink drains and rotating it was one would at home. Would it be possible to push it past the elbow to reach the skin fitting proper?

Any suggestions/comments welcome short of getting out the wet suit and getting in the water with a screw driver.

Squeaky
 
Good afternoon:

I have one of those thingies - just didn't remember what they were called as I have not had a house for thirty some years. I would like to know if anyone thinks it could be inserted down the exit hose past the seacock, elbow and into the skin fitting.

If so I could try rotating it to remove any barnacles etc or what ever is blocking the discharge.

Cheers

Squeaky
 
We have a similar system. Found a pressure washer or high volume sink plunger used from outside to be the only effective method. Our outlet can just be reached from the surface, hanging over the edge of the inflatable.
 
I bought a professional version of one of those spring thingies several years ago when someone put moist toilet wipes down one of our loos /forums/images/graemlins/frown.gif I'm sure that I managed to get it all the way from the Jabsco outlet to the seacock. It did not clear the blockage though....still had to close the cock, take the pipe off, turn cock on and stick a large screwdriver down. Luvverly job....

Yes, it might work. I paid around €20 for mine but it is a very good quality stainless one.
 
I get about one blockage every year. The solution is always the same. Fit a length of hose to the hand pump and pump out until the level is below the inspection cover. Open the cover and strip to the waist. With a short piece of wood or plastic water pipe push the solids out of the drain hole. You will probably need to be able to get your arm fully into the tank - hopefully its long enough (your arm). It goes every time.

One piece of advice - don't do this immediately after dinner.
 
Check our blog, been there a number of times!

One thing I found (if you are brave enough) is to dive over the side with a long piece of hooked flexible steel (I use an old BBQ skewer bent into a hook at the end), wiggle it up the sea-cock outlet and wait for the show! Normally its a piece of babywipe or such like - always comes out attached to the hook. If its gravity fed the deluge just doesn't happen, you have plenty of time to get out of the way.

Not the most pleasent way to empty the thing, but its a lots easier than fishing around up to your armpits in it. At least you can't smell it, get covered in it and its not in the boat; worth a shot.
 
I second Aberman's approach. Works for me every time. Luckily, tho' I can just reach the outlet by leaning over the side of the dinghy...so no need to get wet (or cold!)
 
[ QUOTE ]
Good afternoon:

I have a s/s holding tank which is emptied by gravity ...

[/ QUOTE ]I have been following this thread with interest -- there is no perfect answer to the sewage problem though we haven't had a problem to date.

We have a plastic holding tank that takes sewage from our forward heads via a Y selector valve. The holding tank is emptied either at deck level when facilities exist (they never have in our ownership) or into the sea, through a Blakes, with a dedicated Henderson. So far (liveaboard 365/365 since 2004) we have had no problems with the holding and discharge system (and very few problems with our Jabsco toilets, either, it should be said).

The idea of a gravity discharge for raw sewage sounds daft to me. Stainless tanks will fail, and fail badly, in time.

From my personal experience and having watched threads on this subject since 2004, trying to learn from others' experience, tells me that your best solution would be to exchange the ss tank for a plastic tank, and pump it out with a Henderson.
 
Good Evening Lemain:

I was always told that what goes up comes down. If liquid is pumped up and into a tank which has an opening at one end, it seems to me that the liquid would run out of the tank especially if the end with the opening is lower than the end with the input fitting.

I accept that plastic tanks might last longer than s/s however in the real world one must use what is available and what can be constructed to fit the space available. Mine developed a leak in one corner after about 5 years but was easily repaired without creating too much difficulty.

In any event my original question concerned the possiblity of forcing a dyna-rod around and through a 90 degree elbow at the outlet end of the exit pipe to reach the build up in the skin fitting.

I don't have much control over the type of system I use having used it for well past l0 years now. There definitely would not be room to install a Henderson pump in the exit hose.

I have travelled a lot during my lifetime but I have yet to reach Utopia.

Cheers

Squeaky
 
[ QUOTE ]

I was always told that what goes up comes down. If liquid is pumped up and into a tank which has an opening at one end, it seems to me that the liquid would run out of the tank especially if the end with the opening is lower than the end with the input fitting.

[/ QUOTE ]

But experience tells you that it doesn't (always) and there are many other contributors to this thread who have also found that their understanding of gravity doesn't always work well with holding tanks. I have never heard of anyone with a modern pumped system having to rod their system from under the boat, while in the water /forums/images/graemlins/shocked.gif

[ QUOTE ]
I accept that plastic tanks might last longer than s/s however in the real world one must use what is available and what can be constructed to fit the space available. Mine developed a leak in one corner after about 5 years but was easily repaired without creating too much difficulty.

[/ QUOTE ] It is hard to think of a material less suitable than stainless.

[ QUOTE ]
In any event my original question concerned the possibility of forcing a dyna-rod around and through a 90 degree elbow at the outlet end of the exit pipe to reach the build up in the skin fitting.

[/ QUOTE ] Indeed, and I replied giving you my experience of those devices a few posts above, in message #2187221

[ QUOTE ]
I don't have much control over the type of system I use having used it for well past l0 years now. There definitely would not be room to install a Henderson pump in the exit hose.

[/ QUOTE ]

The Henderson could be anywhere between the holding tank and the seacock -- I am talking about top-exit fittings connected to a modern plastic tank, not pipes connected to the bottom of a corroding stainless gravity tank.

[ QUOTE ]
I have travelled a lot during my lifetime but I have yet to reach Utopia.

[/ QUOTE ] Me neither. We are in Fiumicino at the moment. I don't have the C-Map cartridges or the pilot for Utopia /forums/images/graemlins/wink.gif I do, however, have a working holding tank and at times that can be close to Utopia /forums/images/graemlins/smile.gif
 
Lemain,
I suggest you actually read the posts, as it seems you do not understand what it is actually about!

The gravity system is simple and very effective, with no extra pipework and pumps; its called the KISS system-I'm sure even you can work out what that means. The system works 95% of the time, the only time it fails is when somebody (usually a non-boaty visitor) puts paper or a baby-wipe into the system. The latter in my experience nearly always gets caught at the 90 degree bend at the outlet. So the easiest way to clear is as descibed in the above posts.

There is no mention about the pros and cons of such a system, and as you have obviously have a better, more reliable system than anybody else, that never clogs your posts are irrelevent to this thread. So kindly go and annoy somebody else.
 
[ QUOTE ]

I suggest you actually read the posts, as it seems you do not understand what it is actually about!

[/ QUOTE ]

It is you who needs to read the posts. In the first (original) post Squeaky says "Any suggestions/comments welcome short of getting out the wet suit and getting in the water with a screw driver". I have made comments and suggestions. If that has annoyed you then I am very sorry but stainless tanks are a no-no and we hear nothing but problems from owners of gravity tanks. Such are the facts.
 
Think you are right about stainless tanks - they don't like urric acid and welds can be a problem.

However, not sure about gravity vs pumps, because my experience (for what it is worth) and what I hear from others it is pumped systems that give the most problems. That is why I did not order the tank on my boat - the thought of lengths of 38 mm pipe full of s***t running round the boat and reliant on a pump as the only means of emptying did not appeal. If a gravity tank has an inspection plate immediately above the outlet it is easy to clear on the rare occassion it might block.

And it can be rodded - which answers Squeaky's question.
 
Good Evening Lemain:

Could you please explain what material that is readily available should be used for holding tanks other than s/s?

I don't think this forum has a means of closing a post but if it did I would indicate that this one is closed because I have since realized that a bit of thinking would have made me realize that it was unnecessary - had I thought about it a bit more I would have realized that I could have conducted my own test by obtaining a similiar elbow and a length of hose and attempting to run the dyna-rod through it.

However maybe all is not lost because maybe I am about to learn something the construction of holding tanks.

Cheers

Squeaky
 
Have a look on here www.tek-tanks.com They are the leading (but not the only) manufacturer of plastic tanks. They made my gravity system for my old wooden boat - helped with the design and I am very satisfied. Vetus is also a good source and their catalogue has a wide range of types of tanks.

Hope this helps
 
[ QUOTE ]
However, not sure about gravity vs pumps, because my experience (for what it is worth) and what I hear from others it is pumped systems that give the most problems.

[/ QUOTE ]Well, I don't have any hard numbers but I've been following threads on things that concern me in these forums for many years. I seldom hear of any major problems with pumped systems.

The problem, fundamentally, with gravity systems, is that the maximum pressure available to force the contents through the seacock is equal to the height of the liquid. If you have to resort to opening the tank and rodding, you have a pretty horrid job. Stripping down and servicing a Henderson -- even one that has been used to pump raw sewage -- is probably less unpleasant as you can drop the parts in a bucked and clean them off before working on it. Anyway, a Henderson should be OK for five years, at least, unless you have a most unusual diet /forums/images/graemlins/wink.gif
 
Sorry to dual-post to yours but I thought that this needed a comment....

[ QUOTE ]
That is why I did not order the tank on my boat - the thought of lengths of 38 mm pipe full of s***t running round the boat and reliant on a pump as the only means of emptying did not appeal.

[/ QUOTE ]

The system on my yacht installed by Nauticat was a ss tank with toilet hoses from the aft and forward heads, both Jabscos, and a Henderson pump-out. Our survey (and our noses) picked up the leaky tank (at age 5 years!) so we installed the Tek Tank but left the Henderson in place. I disconnected the aft heads from the holding tank (left the pipe in place, cleaned and blocked). So now the fwd Jabsco either discharges direct through the seacock, or, via a Y diverter valve, to the top of the Tek Tank. The Y valve is 'hidden' under the wash basin and only those who we trust are shown how to use it.

All connections to the Tek Tank are from the TOP. I believe that this is the best way.

Don't forget that some faecal matter can be remarkably solid. Some paper can clog, as well. A decent pump must be better than a rod?
 
The OE installation on mine was on the opposite side of the boat with over 4m of hose running through the bilge from loo to tank and an additional skin fitting. Reported loads of problems with it. However difficult to find space in loo compartment to fit a gravity tank, although think I have it sussed now, but needs a bulkhead taking out etc etc.

The gravity system I have in my old wooden boat has a Lavac which I think makes a very good job of breaking up. All fittings grouped in the top with inspection hatch over outlet and pipe to Blakes with a good fall - no angles. Every thing goes through the tank - simplicity itself. Don't use it enough to know whether it blocks, but doubt that it will.

Similar layouts in later production Bavarias are nowhere near as good with tanks hidden, sloping tops and 90 degree bends in the outlets.

Lovely subject!
 
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