Budget Heath Robinson Holding Tank

S

saltyrob

Well-Known Member
Joined
11 Apr 2004
Messages
394
Location
Suffolk
Visit site
Hi Folks

With the full encouragement of the Mrs Saltyrob and unlikely encouragement of elder teens who want to join us for some reason ,its oft to Holland next year, after a break of several years.Wishing to respect their rules, I have started thinking about a holding tank installation and to put this into context, the installation must be cheap, very cheap, so here's the idea. We have 28 ft yacht with limited stowage space in the cockpit lockers and no room for a porta potty, but there is a small wet hanging locker behind the toilet.The idea is to put a camping type waste water container in the locker. The waste pipe from w.c goes up in a loop in the locker and down to the seacock outlet. On the downward side of the loop will be fitted a diverter valve with waste pipe connected to the container. A 15 mm vent pipe with carbon filter would be fitted to the tank to discharge outside the boat.The messy bit will be disconnecting the pipe work to allow the container to be carrier to a on shore toilet and disposal, haven't yet figured a way of doing this hygienically.

The tank capacity does not need to be large as we usually spend evenings in marinas/harbours and the islands in the inland waters often have toilet facilities,
really only used if we get caught short during the day and to keep the authorities happy.

Any advise, ideas,dire warnings will be gratefully recieved.Also info as to how do onshore pump out facilities work

I realise this is a slightly wacky idea but,limited budget could be the mother of invention

Many thanks

Rob
 
Did something similar to placate the US Coastguard holding tank inspections in Florida.

A black bin bag attached to the OUTLET hose with a Jubilee clip, [ large elastic band works as well ]
Bag sat in a large plastic bin. I only used it a few times and disposal was not too difficult or smelly.

I never did any serious sailing with it but see no reason why it would have failed.

OH YES I NEVER OVERFILLED IT - TO HORRIBLE TO CONTEMPLATE.
 
I hope this helps, but possibly may not.
The holding tank (stainless steel but could be plastic) on my Finngulf sits in the bottom of the cockpit locker immediately behind the loo. They have built a nice flat removable floor in flow coated ply over it, which allows me to separate the locker contents neatly. The Jabsco loo discharge pipe pumps everything in to this tank. There is a looped vent pipe from the tank which discharges above water level then down below the transom step well out of the way. A Whale bilge pump on the back of the bulkhead between loo compartment and locker is pumped from behind and above the pan and is dedicated to discharge the tank through a loop then down to the normal type of seacock in a locker below the loo sink. (A second Whale hand pump immediate below it empties the shower drain and can also be used to supplement the emergency bilge pump in the cockpit). There is an deck cap and drop pipe for inserting a shore pump out station tube, but to date we have only ever pumped out at sea. I tend to pump out and flush routinely every time we leave the canal or harbour. We have no diverter valves everything from the loo has to pass through the tank, but I think they are more fastidious in the Baltic than the UK. (In late season when I keep my boat in Ardrishaig basin it quickly gets a thick sewage scum around the water line which is a pain to remove, not discharge from my own boat but from the others near it, I am beginning to strongly favour effective holding tank systems especially in canals and inland waterways, BW do have a regulation but you can judge how much it is applied by the very infrequent use of the shore facilities).
I have had an occasional problem with this vent arrangement; because the vent outlet is immersed by the stern wave when we are going really fast and at the same time the contents are getting very agitated creating some gas pressure, we can get a smelly blow back of a little of the contents in to the loo pan.
So make sure you have a vent that is always clear and works.
 
Last edited:
You won't be able to use the pump outs because they have a rubber nozzle that inserts into a 38mm deck fitting. You would NOT want to bring that into your boat even if it did fit. A cheapo container would also collapse under the suction as a small vent wouldn't replace the sucked air quickly enough. I have a 38mmm vent and the charcoal filter came with a warning about this. There weren't many pump outs when we were in Holland this year anyway so a discreet emptying in tidal waters was necessary. So be prepared for carrying it ashore for disposal and bear in mind the weight once fullish. As an emergency facility it sounds effective. A translucent container will show how much is in it but......:o
 
Sounds pretty dubious to me. I suppose as an emergency pee-only facility it might just do, but even then I'd expect it to smell after a little while. Plastic isn't actually impermeable; proper tanks work because the walls are thick enough that it won't leach through over a reasonable lifetime, but that's not true of a collapsible water bag.

---

EDIT:Oops - just seen you were talking about a *waste* water container. I was imagining one of those thin-walled cubes used to carry fresh water. If you mean the kind of black plastic jerrican my parents used to have under their caravan for sink wastes, I'd be a bit less negative about it. Still not keen on a sewage system that routinely requires to be opened inside the boat though.

Pete
 
Last edited:
Many thanks for your comments. I would probable only keep the tank on board for the duration of our holiday , say three weeks. Also could add some Elsan fluid to the flush to keep things sweetish in the aroma department.

Rob,( the reluctant sanitary technicin)
 
I have fitted a porta-potti instead of the sea toilet - which I guess you don't want to do. The holding tanks I have might be of interest though. I have two of those waste water tanks (as you suggest) doing duty as loo holding tanks. The waste-water tanks are fitted with a dinghy bouyancy tank hatch to allow easy pour-in from the porta-potti and a breather valve to allow easy pour-out. The breather valve is simply a 1/2 inch pipe fitting with a screw-on cap. Just remove the cap before pouring, so the gloop goes down in a nice easy flow without splashing (The porta potti comes already fitted with one). I carry the holding tanks ashore to empty. A possibly useful point for you is that, if you use the blue fluid in the correct measure, all bugs are killed and thus, the holding tank does not need a vent, except for filling.


Cheers! Neil
 
saltyrob said:
Many thanks for your comments. I would probable only keep the tank on board for the duration of our holiday , say three weeks. Also could add some Elsan fluid to the flush to keep things sweetish in the aroma department.

Rob,( the reluctant sanitary technicin)
Click to expand...

Don't fit a holding tank unless you are going to do it properly. For temporary use take out the sea toilet and fit a chemical toilet.

The easiest and cheapest proper holding tank is a gravity tank fitted above the waterline on a bulkhead and discharging through the normal outlet. Very simple and the type most used by production builders today. Avoid pumped systems and diverter valves and anything complicated. Suggest you look on the websites of Lee Sanitation and Tek Tanks to get some ideas on layouts.

The big problem with a small yacht is that it is difficult to find a suitable place to fit a tank of any useful size (40-60 litres) so you will probably need a custom tank. A standard size/shape tank of that size is in the price range of £200-300 and a custom tank £4-600. Fittings are typically £100 extra. if your boat is a regular production boat Tek Tanks may already have a design available.

If you get into a pumped system costs will be roughly 50% higher than the ranges quoted.

Regrettably there is no reliable "cheap" alternative.
 
Best idea (which I will crib) is the Porta Potty fitted with a low outlet and a Henderson bilge pump to a skin fitting. Enough capacity for a few days and dead cheap. Don't forget a big antisyphon loop.
A
 
Hi,

We will spend about two weeks in non tidal inland waters , therefore no discharge from boat, so either the effluent storage needs to be portable so that it can be emptied on land or suitable for pumping out. The pump out option will require a more high tech expensive approach , hence the portable container may be more suitable.

Rob
 
The problem with any portable sewage tank, Porta-potti or any such device is that marinas and ports have no official facility for the disposal of their contenets. Camping and caravanning sites always have a dedicated chemical toilet disposal drain, usually well designed with tiled, funnel shaped sides and a washdown hose. I have yet to see a port with any such facility. This means that you will have to sneak your container into the toilets, tipping it down the loo and inevitably splashing the walls, seat and floor with no means of washing it down. You are then faced with flushing it out, presumably using the tap and hoses that others will use for their potable water?

A further problem is that many toilet sewage treatment systems cannot cope with the chemicals used in portable toilets, which kill off the bacteria. In many French motorhome facilities the grey and black water must be dumped in separate drains.

I would do as most Dutch boat owners do, inland or at sea. Use the sea toilet.
 
When in Holland last year I had a porta potti in my Moody 31 compartment .A bit of a tight squeeze but we managed.An alternative is the Flex Toilet bag.They sell these in the chandlers in Holland.They are like a big nappy bag which folds over the existing loo.They soak up the you know what and you fold them up like a nappy and dispose in the general rubbish.(so a Dutchman told me www.flex-toilet.nl/video.html
 
A fiver a day and you can keep your ****e in a bag. Great.
Who comes up with anything as revolting as that? "Basically Flex Toilet should be part of the standard boat inventory [...] particularly when entertaining friends or business relations."

Always thought the amount of plumbing you put between your arse and the open sea would be the yardstick of civilisation.
 
This reminds me of my past caravanning days (before I became civilised). Occasionally having to empty the porta-potti discreetly down the normal loo where no proper disposal facilities existed. Being careful not to splash and making sure all was flushed away. Does pong a wee bit though, wouldn't want to go back in there for about 10 minutes!
 
You must log in or register to reply here.

Share this page

Top