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Sea toilet to vented container?


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My Vacuflush cassette toilet is finally starting to have a few problems after nearby 16 years of liveaboard use. The docking station is out on the bow deck waiting for me to take the vacuum pump apart and clean it out.

 

Anyway, I know sea toilets are designed to either pump overboard or into a pump out tank but I was wondering whether a sea toilet bowl could be connected to a 25 litre plastic container rather than a pump out tank? I'm actually surprised nobody has come up with a carry off vented tank at least there's nothing that I can find on the market. 

 

It probably wouldn't take too much effort to make something myself, but you'd obviously need a way of knowing when it was getting full and venting through a carbon filter or overboard.

 

Although I prefer cassettes I find the range of cassette toilets very limited and apart from the vacuflush they're all plastiky affairs which is why I was thinking of a porcelain sea toilet.

 

For the sake of everyone's sanity, I'm not interested in pump out toilets. I've lived with both and I know which is better for me, so don't bother to suggest it please.

Edited by blackrose
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1 minute ago, blackrose said:

Anyway, I know sea toilets are designed to either pump overboard or into a pump out tank but I was wondering whether a sea toilet bowl could be connected to a 25 litre plastic container rather than a pump out tank? I'm actually surprised nobody has come up with a carry off vented tank at least there's nothing that I can find on the market. 

 

Our 'Sea Toilet' runs into a tank via 'grey waste water pipe' (38mm ?) no reason why it shouldn't run into a 25 litre container instead, as long as it is lower than the toilet I cannot see any problem.

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2 minutes ago, Alan de Enfield said:

 

Our 'Sea Toilet' runs into a tank via 'grey waste water pipe' (38mm ?) no reason why it shouldn't run into a 25 litre container instead, as long as it is lower than the toilet I cannot see any problem.

 

They won't pump up a couple of feet if the opening is on top of the container? I was thinking of a manual pumped version.

Edited by blackrose
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4 minutes ago, blackrose said:

 

They won't pump up a couple of feet if the opening is on top of the container? I was thinking of a manual pumped version.

 

I really don't know, there is obviously some 'hydraulic motive force' pushing the 'logs' but ours is 'gravity fed'. The stern en-suite toilet is about 20+ feet away from the tank so maybe needs gravity to assist over such a long run.

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I remember a friend of mine had a Springer in the 1980's that had exactly that. A sea toilet that pumped into two 25 litre plastic jerry cans he kept in the engine space under the rear deck. He just lifted them out for emptying. I can't say it appealed to me but it is an option if you already have a sea toilet and use a diverter valve. I prefer to have a couple of spare bottoms for the porta potti.

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1 hour ago, Alan de Enfield said:

 

Our 'Sea Toilet' runs into a tank via 'grey waste water pipe' (38mm ?) no reason why it shouldn't run into a 25 litre container instead, as long as it is lower than the toilet I cannot see any problem.

I have a manual pump 'sea toilet' with a conventional holding tank which is below the 'throne'. I can see no reason why my tank could not be replaced with a removable one. Positioning this tank above the bowl/pump would be problematical. Any waste, liquid or solid, is ejected by water pressure. Once this pressure is removed any content within the exit pipe will naturally drain back into the bowl. I have sailed yachts where the sea toilet pumped into a holding tank that was above the toilet (and later discharged overboard by gravity). Those toilets worked on a hand pumped vacuum principle. Can't remember the details apart from the fact that kneeling on the lid aided building up the vacuum. If you were to go down the sea toilet line it's worth going going for the larger bowl and wooden seat. Almost like being at home  😆   

Edited by Slim
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Some years ago Lee Sanitation produced a toilet that had a standard ceramic dump-through toilet bowl sitting on a box which contained a standard thetford cassette. It was meant to give the quality feel of a ceramic toilet with the flexibility of a cassette system.

As I remember it was all a bit of a lash up, which is presumably why it didn't last long.

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We changed our aged cassette toilet for a new Thetford C263-CS cassette with ceramic bowl, easier to keep looking good than the plastic one, but still only 15 or 17 litre capacity and still on a plastic base. Just a thought.

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1 hour ago, David Mack said:

Some years ago Lee Sanitation produced a toilet that had a standard ceramic dump-through toilet bowl sitting on a box which contained a standard thetford cassette. It was meant to give the quality feel of a ceramic toilet with the flexibility of a cassette system.

As I remember it was all a bit of a lash up, which is presumably why it didn't last long.

They certainly did, it was circa 20 years ish since. I looked at one, the idea that appealed was that if you remember the cassette pulled out at the front of the toilet sort of between were you legs are so the bog could be fitted flush to a bulkhead and always be able to retrieve the cassette. Didnt last long at all but I dont know why.

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3 hours ago, Mike Adams said:

I remember a friend of mine had a Springer in the 1980's that had exactly that. A sea toilet that pumped into two 25 litre plastic jerry cans he kept in the engine space under the rear deck. He just lifted them out for emptying. I can't say it appealed to me but it is an option if you already have a sea toilet and use a diverter valve. I prefer to have a couple of spare bottoms for the porta potti.

 

Surely it's an option if you wanted to buy a new sea toilet too?

 

I wouldn't fancy doing what your friend did either by the sounds of it. I don't really understand how he prevented overfilling/ overflowing his tanks? It's not quite as simple as just pumping waste into tanks, you need a way for the headspace to escape as you pump waste in without causing odours and also a way of indicating when a tank is say 80% full.

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3 hours ago, Slim said:

I have a manual pump 'sea toilet' with a conventional holding tank which is below the 'throne'. I can see no reason why my tank could not be replaced with a removable one. Positioning this tank above the bowl/pump would be problematical. Any waste, liquid or solid, is ejected by water pressure. Once this pressure is removed any content within the exit pipe will naturally drain back into the bowl. I have sailed yachts where the sea toilet pumped into a holding tank that was above the toilet (and later discharged overboard by gravity). Those toilets worked on a hand pumped vacuum principle. Can't remember the details apart from the fact that kneeling on the lid aided building up the vacuum. If you were to go down the sea toilet line it's worth going going for the larger bowl and wooden seat. Almost like being at home  😆   

 

Yes that's a good point about waste draining back into the bowl. I assumed once it had been pumped through it couldn't come back. I don't really understand how they're made to work in conjunction with remote pump out tanks unless the bowl is always higher up on a pedestal. My idea might be a non-starter then as I wanted the toilet at floor height.

2 hours ago, PeterF said:

We changed our aged cassette toilet for a new Thetford C263-CS cassette with ceramic bowl, easier to keep looking good than the plastic one, but still only 15 or 17 litre capacity and still on a plastic base. Just a thought.

 

Thanks, I'll have a look at it.

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Yacht Waitangi has a sea toilet pumping up to a holding tank well above the level of the head. Yes the contents of the outlet pipe do drain back into the bowl, incentivising a couple of seawater flushes after the payload to keep things sweet if the boat is left for a week or so.

The difficulty I see is the holding tank, must be vented to displace the foul air above the contents to make room for the new load. In our case this is via a charcoal filter that requires frequent replacement, and loop up to just under the deck to drop to a hull penetration fitting well above normal water level. You certainly would not want the vent to be anywhere near occupied space even with a new charcoal filter.

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1 hour ago, DandV said:

 

The difficulty I see is the holding tank, must be vented to displace the foul air above the contents to make room for the new load. In our case this is via a charcoal filter that requires frequent replacement, and loop up to just under the deck to drop to a hull penetration fitting well above normal water level. You certainly would not want the vent to be anywhere near occupied space even with a new charcoal filter.

 

The venting issue is no different from what I currently do with my vacuflush toilet - all the pipework, filter and skin fitting are already in place, so I don't see that as the difficulty.  

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13 minutes ago, blackrose said:

 

The venting issue is no different from what I currently do with my vacuflush toilet - all the pipework, filter and skin fitting are already in place, so I don't see that as the difficulty.  

As I see it the container would  a separate vent and an inlet. Not insurmountable. I think some polyethylene fuel containers are so equipped but from memory the vent might need enlarging to use them.   And I forgot to add the discharge PPE fro the head passes up to an inverted U piece complete with a syphon break, such fittings are readily available from chandlers.

Good luck. 

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11 hours ago, Mike Adams said:

I prefer to have a couple of spare bottoms for the porta potti.

 

 

Doesn't the "bottom" you already have provide you with sufficient output to keep your toilet active ?

 

 

 

Sorry - it (I) picked up your quote of another post, within your post.

 

 

8 minutes ago, blackrose said:

 

Once again you've managed to quote someone else and attribute it to me....🤔

 

 

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8 hours ago, blackrose said:

I wouldn't fancy doing what your friend did either by the sounds of it. I don't really understand how he prevented overfilling/ overflowing his tanks? It's not quite as simple as just pumping waste into tanks, you need a way for the headspace to escape as you pump waste in without causing odours and also a way of indicating when a tank is say 80% full.

Well I guess he was normally the only one onboard so he knew roughly when it was likely to be full and the containers were transparent anyway. I think he just had an airhole in the lid of the one in use.

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8 hours ago, blackrose said:

 

Yes that's a good point about waste draining back into the bowl. I assumed once it had been pumped through it couldn't come back. I don't really understand how they're made to work in conjunction with remote pump out tanks unless the bowl is always higher up on a pedestal. My idea might be a non-starter then as I wanted the toilet at floor height.

 

Thanks, I'll have a look at it.

My manual pump sea toilet, Jabsco Par, is physically mounted on top of the holding tank with the pipe entering the tank about 5-700mm to the left through a 90 degree elbow. The base of the toilet itself is about 150mm above the floor. Any lower and for me it would be unusable. (also further to aim 😀). The exit pipe comes out of the pump assembly about 75mm up and this ensures that the flow to the elbow is level. A flush / drain allows emptying but it's a fairly basic valve.  

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If you have the Vacuflush loo with a porcelain bowl and a 'ball' with pedal in the bottom of it then I wonder if you could sit it on top of a plastic tank (might need a bit of 3/4 ply and some framing to strengthen it) then a simple manual pump to transfer the contents into a (well labelled !) water carrier or something. Presumably you have an outlet in the hull for the air expelled from the vacuflush pump so you could use that as a vent pipe. Might need a lot of fiddling about to make it all work but it should be OK and the water flushing bit of the vacuflush should still work too. 

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The outlet hose from a yacht toilet is taken up to deck level before exiting through the bottom of the hull or into a holding tank, which is mounted high enough to empty by gravity out at sea or by pumpout in a marina.   The tank has an overflow pipe out through the hull side.   A sailing yacht normally has the toilet mounted below the waterline so needs a U bend to prevent sea water syphoning back in especially when it heels.

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Well, I spent this afternoon taking apart the pump and vent assembly and cleaning it out. For some reason the float in the cassette hadn't activated to shut off the system so it had overfilled and flooded the pump assembly and venting channels. It's all back together now, so it wasn't too bad but I'm just waiting for an o-ring from ebay before I re-install it as one of the o-rings wasn't seated properly in the pipe recess and had been mashed up. Must have been done in the factory as I've never had the pump assembly apart before. 

 

Lee Sanitation have been really helpful with watch-outs for taking the assembly apart and getting it back together without breaking anything. Now I know how to do it I'll probably keep the Vacuflush going for a few more years and postpone the sea toilet idea.

 

I normally rinse the cassettes out a couple of times when I empty them, but I've been advised to give them a good rinse with very hot water to free up the floats. I was thinking of adding some bicarbonate of soda - would that work? I can't think of any rubber seals inside the cassettes that it would affect.

Edited by blackrose
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