Pressurised Thetford cassette

[GUMPY]

23 minutes ago, The Happy Nomad said:

 

I was just about to ask the same. You beat me to it.

 

You can do it if you are very careful (I have on occasions) but its not recommended.

Been doing it that way for many years, but then I don't use normal toilet chemicals preferring bio washing liquid.

I would be surprised if that rots the seal as none of my cassettes leak from there. 

[PaulJ]

4 minutes ago, Loddon said:

Been doing it that way for many years, but then I don't use normal toilet chemicals preferring bio washing liquid.

I would be surprised if that rots the seal as none of my cassettes leak from there. 

Ive only been using bio for the last year and have to say way better as I often dont empty for a while. Currently on Watermelon and Passion fruit I believe 😀

My loo is just basic Porta Potti which I also add bio to the top tank and the seal and blade has never been so clean and definetley no sign of rot. 

[Guest]

Tried all sorts over 40 years.

 

Always come back to double blue especially in warmer climes.

Edited June 18, 2022 by The Happy Nomad

[booke23]

I imagine bio liquid won't damage the seals as it's basically just liquid soap. I've heard many people swear by it, but I'm not sure it would stand up to the abuse I put our cassettes through....ie leaving them nearly full for weeks at a time while we are away from the boat. You can't beat a bit of formaldehyde for long term suppression of bugs. 

[blackrose]

1 hour ago, booke23 said:

 

You're not putting additives in via the bowl are you? That's a recipe to damage the lip seal of the flap. From the manual:

 

No it isn't. It depends what additives you use. Odorloss, biological washing liquid and even the more aggressive Elsan blue won't damage seals. If they did then it wouldn't just be the lip seal of the flap you'd have to worry about. 

 

 

Edited June 18, 2022 by blackrose

[GUMPY]

27 minutes ago, booke23 said:

I imagine bio liquid won't damage the seals as it's basically just liquid soap. I've heard many people swear by it, but I'm not sure it would stand up to the abuse I put our cassettes through....ie leaving them nearly full for weeks at a time while we are away from the boat. You can't beat a bit of formaldehyde for long term suppression of bugs. 

We do have one rule, Always empty the  cassette(s) before leaving  the boat or caravan 😎

 

[booke23]

24 minutes ago, blackrose said:

 

No it isn't. It depends what additives you use. Odorloss, biological washing liquid and even the more aggressive Elsan blue won't damage seals. If they did then it wouldn't just be the lip seal of the flap you'd have to worry about. 

 

It's your toilet so add the chemical how you like. I prefer to be guided by what the manufacturer of the toilet writes in their manual rather than what a blue manufacturer writes on the back of their bottles. 

[Guest]

1 minute ago, Loddon said:

We do have one rule, Always empty the  cassette(s) before leaving  the boat or caravan 😎

 

 

Even when you go to the shops?

 

We turn the water pump off but emptying the loo every time seems a tad extreme...🤪🤪🤪

[sueb]

At least it was a cassette not a pump out tank that exploded. I remember being told at Blisworth boats  the effluent reached the top of the adjacent tree, What goes up must come down!

[GUMPY]

56 minutes ago, The Happy Nomad said:

 

Even when you go to the shops?

 

We turn the water pump off but emptying the loo every time seems a tad extreme...🤪🤪🤪

Only if it takes me more than a couple of days  to get to the shops and back 🤭

[blackrose]

12 hours ago, booke23 said:

 

It's your toilet so add the chemical how you like. I prefer to be guided by what the manufacturer of the toilet writes in their manual rather than what a blue manufacturer writes on the back of their bottles. 

 

I'd rather be guided by the advice of the manufacturer of the particular additive that I'm using. The Thetford advice is very general and applies to any additive including bleach, so they're just covering themselves because they don't know what you're using.

 

If an additive for boat, RV and caravan toilets specifically says it doesn't damage toilet seals that's good enough for me and in 17 years of living aboard I've never had a problem. As I said, if an additive did damage seals then it wouldn't just be the lip seal of Thetford cassette toilets that users would need to worry about as additives are designed to be used with all types of toilets including pump-outs with internal seals exposed to the additive. 

Edited June 19, 2022 by blackrose

[LadyG]

15 hours ago, booke23 said:

 

You're not putting additives in via the bowl are you? That's a recipe to damage the lip seal of the flap. From the manual:

 

I put a splash of cheap Laundry liquid on the closed seal a few times, I thought it would clean and lubricate.

I religiously followed the Blue instructions at first, but it was not a great result, better when I add it every a.m., if you know what I mean!

Seems to be working, I have a Thetford Excellence which leaks out the vent when vertical, I don't think it did this at first, there are no maintenance kits, so I expect I will have to live with it. Not sure if maintenance kits for other cassettes would work. Quite sure I don't want to go down that road.

The Excellence is preferred due to its height, and looks. There are no spares cassettes though, so that would be a drawback with more functionaries on board, I think one would have another unit.

 

 

Edited June 19, 2022 by LadyG

[Alan de Enfield]

49 minutes ago, LadyG said:

I add it every a.m., if you know what I mean!

 

AM = After Motion ?

[booke23]

1 hour ago, LadyG said:

I put a splash of cheap Laundry liquid on the closed seal a few times, I thought it would clean and lubricate.

I religiously followed the Blue instructions at first, but it was not a great result, better when I add it every a.m., if you know what I mean!

Seems to be working, I have a Thetford Excellence which leaks out the vent when vertical, I don't think it did this at first, there are no maintenance kits, so I expect I will have to live with it. Not sure if maintenance kits for other cassettes would work. Quite sure I don't want to go down that road.

The Excellence is preferred due to its height, and looks. There are no spares cassettes though, so that would be a drawback with more functionaries on board, I think one would have another unit.

 

 

 

Nice looking unit those Thetford excellences. Shame about the leaky vent. The hardware on the Excellence cassette does look slightly different to the standard cassettes so I think you might be right on the lack of parts issue. Also the standard cassettes all have an access hatch to enable maintenance, whereas I'm not sure this is the case on the Excellence. 

Edited June 19, 2022 by booke23

[magnetman]

On 17/06/2022 at 20:22, blackrose said:

 

 

. When the flap did open a pressurised aerosol of smelly water sprayed up and hit me in the face. Most unpleasant!

 

 

I saw a boat the other day called "Ship happens" which reminded me of this pressurised cassette issue. 

 

Another approach for onboard toileting is to fit a household lavatory with U bend onto a holding tank. You then fit a Macerator discharge pump routed to a beer keg kept outdoors somewhere. Put a perspex viewing window on it. Keg to also be fitted with a small diaphragm discharge pump and a small 12v battery/holder. The contents will be well broken up and plenty of water so not a problem discharging using something like a whale gusher. 

 

Once the keg is full (2 or 3 days) you can trolley it to the elsan point and discharge it. It's not light at 60kg but probably manageable given sensible arrangements.  

 

Have two beer kegs with the same setups. Clip-on connections. The discharge from the main tank can just be 25mm wire wound Screwfix hose. 

 

It does take up a little more space and manual handling is quite technical but it's really nice having a proper lavatory in a boat. 

 

Specially if one is on a mooring with water. 

 

 

[Alan de Enfield]

2 minutes ago, magnetman said:

Specially if one is on a mooring with water. 

 

Moorings without water are often called 'ashore', or 'hardstandings.

[Naughty Cal]

23 hours ago, The Happy Nomad said:

 

We carried one for a while but found there was no real benefit in doing so as we dont 'wild camp'. It became just something else to store and get in the way.

We carry a spare cassette to increase our time between site visits.

 

Not had a problem with it pressuring yet though.

[magnetman]

2 hours ago, Alan de Enfield said:

 

Moorings without water are often called 'ashore', or 'hardstandings.

Filtration can work but there is nothing quite like municipal domestic water for a proper lavatory. 

 

White vinegar from Tesco (if someone else has not already bought it) is a good additive. Also make sure the onboard tank is well vented with a large bore otherwise it restricts the natural flushing from the cistern of the lavatory. 

 

Proper loos do shift quite a lot of water and the design of the U bend means one does specifically need a clear vent tube of suitable diameter. More than an inch. 

 

 

 

[Alan de Enfield]

36 minutes ago, magnetman said:

Filtration can work but there is nothing quite like municipal domestic water for a proper lavatory. 

 

White vinegar from Tesco (if someone else has not already bought it) is a good additive. Also make sure the onboard tank is well vented with a large bore otherwise it restricts the natural flushing from the cistern of the lavatory. 

 

Proper loos do shift quite a lot of water and the design of the U bend means one does specifically need a clear vent tube of suitable diameter. More than an inch. 

 

 

 

 

 

Our boat has two 'sea toilets' connected to a pump-out tank (or diverted to 'straight over the side) it uses the external (sea or river) water for flushing and does have a U-bend with water sat in the bottom of the porcelain bowls.

We have not noticed any particularly bad smells as a result of the water, but they are flushed on a regaular basis so maybe the water doesn't get chance to 'stagnate'.

Obviously due to the the 'water-trap' (U-bend) the smells cannot get back from the tank into the bathrooms.

 

Edit to add : 

These are the ones we have on the cruiser (one in each bathroom) The waste is 'fed' to the 300 litre tank which is in the bow section by 38mm Grey 'waste pipe' (as used under domestic sinks etc)

 

Marine toilet | RM69

 

 

Edited June 19, 2022 by Alan de Enfield

[GUMPY]

I took a Rheinstrom Y10 off the boat to fit a cassette. It really was a good piece of kit but of no use if the tank has split

 

 

 

https://www.leesan.com/shop/rheinstrom-y10-toilet-compact-bowl-12v-dc.aspx

[blackrose]

6 hours ago, magnetman said:

I saw a boat the other day called "Ship happens" which reminded me of this pressurised cassette issue. 

 

Another approach for onboard toileting is to fit a household lavatory with U bend onto a holding tank. You then fit a Macerator discharge pump routed to a beer keg kept outdoors somewhere. Put a perspex viewing window on it. Keg to also be fitted with a small diaphragm discharge pump and a small 12v battery/holder. The contents will be well broken up and plenty of water so not a problem discharging using something like a whale gusher. 

 

Once the keg is full (2 or 3 days) you can trolley it to the elsan point and discharge it. It's not light at 60kg but probably manageable given sensible arrangements.  

 

Have two beer kegs with the same setups. Clip-on connections. The discharge from the main tank can just be 25mm wire wound Screwfix hose. 

 

It does take up a little more space and manual handling is quite technical but it's really nice having a proper lavatory in a boat. 

 

Specially if one is on a mooring with water. 

 

 

 

Can you post a few pictures if you have time? Sounds like the best of both cassette and pump out worlds.

 

When my old Vacuflush started malfunctioning the second time, I considered a sea toilet pumped into 20 litre jerry cans, but detecting when the jerry cans were getting full, venting them and taking the shit pipe out to empty them without drips & spills put me off the whole idea. 

[magnetman]

To be fair I have not actually executed this solution for using at elsan disposal points. The pipe connections would be a bit annoying. 

 

It could work though. The waste from this type of setup is quite manageable. It's not like pumping direct from a holding tank as it will have gone through a macerator pump already. Also household loos use a lot of water so it's not a slurry. 

 

Household suite mounted on top of well vented rigid (316 stainless ideally) holding tank. Jabsco / other macerator pump which shifts the waste through 1 inch tubing onwards to the beer keg which will be outdoors .

  Quick release hose fittings on the beer keg. You will find that this tube will not end up darkened because the material is in a liquid state rather than being a slurry. There will be small spillage when disconnecting but really not much to speak of. 

 

Perspex dome on top of keg for eyeballing the contents and drill a few holes in the dome for the ventilation. You could fit a float switch but eyes are more reliable. 

 

It could be done. 

 

Quite a heavy thing to move about 

 

 

 

 

 

 

 

 

 

 

 

Edited June 20, 2022 by magnetman

[Sparks Ashore]

I've just experienced the pressurised tank explosive decompression (urine enhanced ), and when investigating ran aground on this forum.
I was actually on a camp ground but being interested in canals, having been brought up near the river Lee Navigation I've joined up. 
I'll leave up the gory details but I couldn't open the flap before using and when I turned it hard there was a mini explosion covering me and the cubicle.
Top tip number one is put the lid down first. cleaned up and all ok until after the journey home when it pressurised again. It was really hard to pull out the cassette. It looks like there is a depressurisation valve that operates to depressurise when you remove the cassette. You have to get it moving first before t will operate though..
I am wondering if the chemical used makes a difference. I'm using a "green" one. Bio washing liquids by the way contain enzymes that help with eating blockages in drains etc. left overnight or while you are way. Enzymes are used on aircraft to help clear galley drains. 
Rob

[Tracy D'arth]

On 20/06/2022 at 09:41, magnetman said:

To be fair I have not actually executed this solution for using at elsan disposal points. The pipe connections would be a bit annoying. 

 

It could work though. The waste from this type of setup is quite manageable. It's not like pumping direct from a holding tank as it will have gone through a macerator pump already. Also household loos use a lot of water so it's not a slurry. 

 

Household suite mounted on top of well vented rigid (316 stainless ideally) holding tank. Jabsco / other macerator pump which shifts the waste through 1 inch tubing onwards to the beer keg which will be outdoors .

  Quick release hose fittings on the beer keg. You will find that this tube will not end up darkened because the material is in a liquid state rather than being a slurry. There will be small spillage when disconnecting but really not much to speak of. 

 

Perspex dome on top of keg for eyeballing the contents and drill a few holes in the dome for the ventilation. You could fit a float switch but eyes are more reliable. 

 

It could be done. 

 

Quite a heavy thing to move about 

 

 

 

 

 

 

 

 

 

 

 

How would you legally own a beer keg?

[Sparks Ashore]

Trying to sort the pressurisation issue I've removed the automatic vent valve and cleaned it. You can remove the cork float and seal then agitate it in a container of warm disinfectant. It was very mucky but still sticky when clean.  Spraying with silicon oil made a real difference. I'm hoping it makes a difference in service.
I've got a pic but you might be eating your tea!

The function of it isn't documented very well but it seems to vent the tank as you remove and refit the tank. A bump above it depresses the valve (a pressurised tank is still hard to start moving).
The float closes part of the valve to stop anything getting in to it. (supposed to anyway)
I think the best way to depressurise the tank is to carefully release the dump cap. Fitting a manual release valve to the dump cap would be a good modification...
The valve i removed is about £13. 
For anyone wanting a spare cassette they are currently around £100  and some have wheels fitted.

 

Edited September 18, 2022 by Sparks Ashore
spellin..