Easy-Peesy-Holding Tank

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dje67

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I'm looking to install a small holding tank to the bog.

My boat is mainly used for day-sails with the odd long weekend or weeks holiday and I tend to use marinas much of the time. So, the holding tank simply needs to have enough capacity for a couple of flushes at night and will normally be discharged to sea once out of the marina.

I've been doing a quick look around at the options available and came across the tank in the link below:

http://www.marinescene.co.uk/product/3923/plastimo-25-litre-mini-toilet-waste-kit

Questions:

Anyone used this type of tank? Any problems?

Given the low cost, compared to a custom tank, does this seem a good option?


Thanks,
David
 
It's actually a Raske and van der Meyde tank

and will probably not fit anything but an RM69 toilet.

I've had one for about 8 years. As a retrofit it just passes muster BUT,

the changeover valve is fragile,
the down-pipe inside the tank is prone to come off.
it's hell to get smell-free after use - you have to pump through for hours
 
Why not do the same as most mediterranean charter boats - simply put a small tank in the waste pipe and then when you want to discharge - preferably some way offshore - open the outlet valve and let gravity do the rest. Simple and effective. If you've no aspirations to being able to empty the tank in a marina, then I can't see why you would need anything more complex. I've not done a DIY installation, but wouldn't have thought it would be difficult.

Neil
 
The tank is made by RM but fits many types of toilet, certainly Jabsco. I had one until recently but the changeover valve is badly designed, too complicated and was constant trouble. The toilet pump is used to empty the tank but it is not very efficient, extended pumping wears out the pump seals and the bottom inch in the tank cannot be emptied, hence the smell.

Far better to go for a simple gravity tank, as already suggested. I am part way through the conversion from the RM to a gravity tank.
 
vyv_cox said:
The tank is made by RM but fits many types of toilet, certainly Jabsco. I had one until recently but the changeover valve is badly designed, too complicated and was constant trouble. The toilet pump is used to empty the tank but it is not very efficient, extended pumping wears out the pump seals and the bottom inch in the tank cannot be emptied, hence the smell.

Far better to go for a simple gravity tank, as already suggested. I am part way through the conversion from the RM to a gravity tank.
Click to expand...


I'm sure you will engineer your system better than I did but I had awful problems with my gravity system. Paper in the tank would settle against the closed sea cock and form a solid papier mache type plug :(:(
I also know of this happening in a Dehler 36 gravity tank system:(:(

VERY difficult - and smelly - to resolve!!
 
BAtoo said:
I'm sure you will engineer your system better than I did but I had awful problems with my gravity system. Paper in the tank would settle against the closed sea cock and form a solid papier mache type plug :(:(
I also know of this happening in a Dehler 36 gravity tank system:(:(

VERY difficult - and smelly - to resolve!!
Click to expand...

You need to be careful with the type of paper you use. Putting masses of double-strength papers down can give problems, better to use the lighter stuff designed for the job.

Also, many gravity systems have the pump-out fitting immediately above the discharge port so that it can be rodded through from on deck.

A glug of that portapotti blue stuff down the loo each time after you empty it should see to that.
Click to expand...

Not nice stuff to carry on board, environmentally unsound and it doesn't work! I have also tried the 'green' equivalent, as sold at various boat and camping shows. That didn't work either.
 
This is one job (?) that needs to be done properly if it is to be trouble free. A gravity tank is the preferred option for simplicity and low(ish) cost.

Two good sources of information and parts are Lee Sanitation and Tek Tanks. Both sell standard size and custom tankss and the latter may already have done an installation for your boat. Also the owners association is worth a call.
 
If you can fit a tank of about 40 litres it will be a better solution. My boat has tanks fitted above the level of the toilets in both heads. The waste is pumped directly to the tank without any diverter valve, and discharged by gravity. I have only used the deck pump outs to clean the tanks with a hose. As for paper clogs. I have never had a problem, but only use the soluble paper sold by caravan shops for use with caravan chemical toilets.
 
macd said:
Oddly, this never happens if you don't put paper down the loo in the first place
Click to expand...

whats the point of even having a toilet if your to scared to put paper down it? we are in 2010, yes it may be expensive but there is no reason why you cant put bog roll down there, there is good enough technology about to do this.
 
tel1 said:
whats the point of even having a toilet if your to scared to put paper down it? we are in 2010, yes it may be expensive but there is no reason why you cant put bog roll down there, there is good enough technology about to do this.
Click to expand...

You have your perspective, I have mine. As has much of Greece. As for the suggestion that any of this falls under the umbrella of modern technology, I nearly fell out of my dug-out canoe...
 
macd said:
You have your perspective, I have mine. As has much of Greece. As for the suggestion that any of this falls under the umbrella of modern technology, I nearly fell out of my dug-out canoe...
Click to expand...

I feel sorry for you falling out of your dug out canoe. modern technology, let me see, im thinking....... still thinking......... oh yeh thats rite a MACERATOR!!!!! Add that to your so called simple gravity fed holding tanks and you shall soon churn up the fancy andrex paper i put down my loo. NO BLOCKAGES THEN!
 
I agree totally - we don't put anything we haven't eaten down our toilet either on our boat in the Solent, which doesn't have a holding tank, or our one in Turkey, which does. Doesn't stop us using toilet paper though! Have never had a problem with blocked heads.

Neil
 
Has anyone ever wondered what that disgusting slimy mess is wrapped tightly around the dinghy painter in the morning - yes, that's right, used loo roll from all the holding tanks emptied during the night - lovely!!

I, for one, will stay in the dark ages and put my paper in the bin. Oh, saves clogging up the seabed too.
 
So, some interesting replies.

I contacted Tek Tanks and they don't have an off-the-shelf tank.

My boat is a bene 36cc - anyone got a tank already fitted in one of these? Where and
how? Gravity discharge? Macerator?

A couple of people mentioned that the Plastimo tank can cause some smells - is it smell all the time or just when being pumped out (it's turning into a lovely thread...!).

Finally, what tends to go wrong with the diverter valve and is it repairable when it goes wrong?

Ta.
 
For a gravity tank you need to find a space to fit a tank of +/- 50 litres above the waterline. Usual place is in a locker in the loo or in a storage locker the other side of a bulkhead from the loo compartment. Ideally with a clear run for the 38mm outlet from the loo to the tank (it can go in the bottom with a standpipe or in the top with a vented loop) and for the outlet to the seacock. There are two schools of thought on diverter valves. The KISS people like me pump everything through the tank, whereas the pessimistic B&B people like a direct to sea alternative. Lots more pipe, jubillee clips and potential leaks for little benefit IMHO.

The alternative if you don't have space for an above the water line tank you need a convenient locker such as under the bunk to position the tank and then a pump or macerator to evacuate the tank. You do need a diverter valve for this as you don't have the option of pumping through the tank direct to sea. The disadvantages of this type of system, apart from the cost - typically double that of a gravity tank are runs of pipe permanently full of sewage, reliance (usually) on electrics to pump and often an additional seacock, particularly if you use a macerator which is normally a 1" pipe.

To give you an idea, I did not order the standard holding tank on my Bavaria 37, partly because it was hideously expensive but mainly because it was on the opposite side of the boat and there was 3m of sewage filled pipe running uner the sole in the saloon! I have now fitted a 60 litre gravity tank in a locker in the loo compartment.

I can't recall the layout of your boat but would be very surprised if somebody has not fitted one already. Owners Association beckons!
 
dje67 said:
So, some interesting replies.

I contacted Tek Tanks and they don't have an off-the-shelf tank.

My boat is a bene 36cc - anyone got a tank already fitted in one of these? Where and
how? Gravity discharge? Macerator?

A couple of people mentioned that the Plastimo tank can cause some smells - is it smell all the time or just when being pumped out (it's turning into a lovely thread...!).

Finally, what tends to go wrong with the diverter valve and is it repairable when it goes wrong?

Ta.
Click to expand...

First - the tank to which I am referring was made by Raske & Van der Meyde, though as Plastimo manufacture nothing, it's likely to be the same.

Smell is continuous and through the breather.

The diverter valve has a shutter valve, which comes across to block the outlet or tank pipes. The arm on this comes off the control shaft and the shutter-valve falls to the bottom of the assembly - at which point nothing works. It is repairable, but the task is unappetising, mine is heavily beefed up with glass/epoxy. I also carry a spare!
 
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