Toilet waste tanks and fittings

[stuart]

On a waste toilet water holding tank, whats the most commonly found pump out connections at marinas/stations?

eg. pump out pipe diameter, vent hose diameter, required skin fittings etc

[John Orentas]

Stuart.

 

There is only one 'Standard' fitting for pump outs, they have a sealed cap, with a female hexagon cast into it for removal. Needless to say all marina and d.i.y. pumpout machines have the compatible type of nozzle fitting. They are not just common to narrowboats, I have seen the same things on coaches and even aircraft.

 

Your skin fitting, usually mounted on the gunnel is connected to your tank by a 3 inch dia plastic pipe which should be as short and bend free as possible. A vent pipe which may also double as a means to add fluid into the system is also required, skin fittings are made for the purpose but a standard is not required.

 

John Squeers

[Richard Bustens]

Hi

I confer with John except i think it is better to put on the roof for easy access from both sides, other option is a skin fitting on both sides but that means a lot of pipe all over the place.

[Big COL]

Stuart

 

The vent pipe should be equal in size to the pump out pipe, usually 38mm I/D. This is to try and avoid the tank contents from going anaerobic and creating too many offending smells. Idealy the vent should be positioned under gunnel level, I would not recommend bringing a vent up to roof level as you will have a face full of obnoxious fumes when steering. The ideal set up is to have a pumpout fitting on both gunnels and a vent on both hull sides.See Lee Sanitation for a full explanation. Lee Sanitation

Edited November 6, 2004 by Big COL

[John Orentas]

Big Col

 

There are a lot of pronouncements there and very few explanations. Anaerobic, sounds impressive. The dictionary says "An organism which lives in the absence of oxygen"?

 

Perhaps you would tell us, in practical terms how we can install pump-out fitting on the gunnels on both sides. Why should the vent be below the gunnels.

 

Lee Sanitation say that the vent pipe should have an 'area' of not less than 38mm (which equates to 7mm dia). not 38mm dia. The paragraph is very contradictory, the above is probably a misprint.

 

In 25 years of boating I have not once had any kind of problems getting a pump-out because it is on 'the wrong side'.

 

John Squeers.

[Big COL]

John

 

 

I did say ideally, this obviously needs to be thought about at planning stage, the majority of builders now like to have waste tanks across the boat as the trim only alters marginally between full and empty as opposed to having the tank on either side, because the size of the tanks are getting larger and larger and if positioned on the side causes listing. A 100 gallon tank is equivalent to 1/2 a metric ton which equates to a lot of mobile ballast.

On my boat the tank is positioned across the boat with connections for pump out and vent on both sides of the tank, this then allowed me to have a pumpout point on both sides and eliminates the need of dragging pumpout hoses over the roof of the boat. This is my personal preference as it's not the best of situations when they retrieve the hose and leave a trail of waste across the roof.

On the subject of aerobic and anaerobic organisms this is not the place to discuss the advantages/disadvantages, but very briefly you are obviously well aware of the advantage of having anaerobic organisms in the cleaning up of effluent, they do a magnificent job, but the down side is the odour they create in doing so, therefore not suitable for a boat waste tank, which is why the more oxygen that can be let in through the vents prolongs the tank from going anaerobic, but you know all this and I think your tugging my leg to see if I do.

As to the position of the vent, I have always assumed that the lower the vent the more chance the smell has to dissipate before it's at nose level. I cannot see any other logical reason other than this.

 

All the best

Colin

[stuart]

Thanks for your replies guys.

 

After visiting midland chandlers this morning, there "standard" size tank is 48" x 22" x 10" deep. Sells for just short of £200.

 

Any other dealers worth trying or is this price reasonable?

 

I like the idea of putting the tank near the centre line of the boat - dont know if I can fit that in to my design though. How bad would the hull list be if the tank were nearing full?

 

I suppose 10560 cubic inch's of s*** is going to be quite heavy!

[Big COL]

Stuart

 

 

10,560'' cubed equates to approximately 38 Gallons. Weight =380lbs or 172Kg

This was a quick calc on paper please check

 

 

Colin

[John Orentas]

Stuart.

 

Have you ordered a new boat, the builder usually supplies the tank as part of the shell, you really need to go bigger than 40 gallons. As Big Col says try to incorporated it 'across' the boat as much as you can the bow to stern dimension is less important.

 

John Squeers

Edited November 7, 2004 by John Orentas

[Richard Bustens]

Water weighs 10 lb per gallon sh** weighs 14

If you put a breather filter from Vetus you will get no smell at all from the vent, still think it is a pain trying to put a t in the pipe and run it to both sides, far better to put on the roof but not the vent.

[stuart]

Stuart.

 

Have you ordered a new boat, the usually the builder supplies the tank as part of the shell, you really need to go bigger than 40 gallons.  As Big Col says try to incorporated it 'across' the boat as much as you can the bow to stern dimension is less important.

 

John Squeers

<{POST_SNAPBACK}>

 

New boat but no waste tank

 

The "standard" dimensions are a bit small. I have quite a bit of space to put the tank under a rear bed but hoping to get in a full size shower cubicle as well makes planning a small bathroom layout a bit of a pain.

 

I think midland chandlers tanks are made from polypropelene.

 

Can these tanks be made from steel? I could probably get custom one built for me.

[Oliver]

Stuart

 

We have a metal tank along the centre line, under the half the bed (calorifer is the other half), and a full size shower cubicle. Think the tank came from Lee Sanitation but not sure. Picture of it in the FitOut photoalbum on our web site.

 

On our 'old' boat we could tell when we needed a pump out because of the list (tank was on the side). Useful, because I am a bit squeamish when it comes to looking down the dump through to see how full it is.

 

On the new boat, with a remote tank on the centre line, how do we know if the tank is full? We've had a gauge fitted - 'waste level' - no, you can't see the fluid level and whatever is floating it, just a dial and a needle. Hope that will do the trick when we eventually manage to cruise out of the builder's yard.

[John Orentas]

Stuart.

 

It used to be accepted practise that the shell buider also made the pump-out tank, in that way you get exactly what you want, in the size that you want, fitting in with you fitout plan.

 

It should be fabricated from mild steel 4 or 5mm thickness, another advantage is that you can design it to go through the floor and sit on the base-plate of the hull, in that way you will gain an extra 5 inches or so in depth which will make a big difference to it's capacity and it can be fixed down properly. Remember it will weigh up to half a ton, the weight will be low down in the boat were it should be.

 

John Squeers

[stuart]

Think I will try and get one built from steel to the exact size I have to play with.

 

Can you see any problems with this being built as an "L" shape?

 

 

Can you also confirm that the pumpout waste pipe is 3 inch - not 38mm ?

[John Orentas]

Stuart.

 

I have just pulled out my original drawing. I used an 1.5 inch o/dia. steel tube for the outlet pipe, (the plastic pipe fits onto that with jubilee clips). The pipe needs to protrude say 2 inches and passes into the tank leaving a 1 inch gap at the bottom. I fitted a 1 inch o/d vent pipe tube protruding 2 inches though you may prefer to make it 1.5 o/d.

 

The hole for my Mansfield traveler is 5 inch dia. A 'L' shaped tank is ok. Out of interest the dimensions of my tank are: 48 x 20 x 14 inches high, bear in mind it passes through the floor. You should perhaps double check the 1.5 dia by measuring a pump-out fitting, the plastic pipe may well now be metricated.

 

John Squeers

[stuart]

I have just pulled out my original drawing.  I used an 1.5 inch o/dia. steel tube for the outlet pipe, (the plastic pipe fits onto that with jubilee clips).  The pipe needs to protrude say 2 inches and passes into the tank leaving a 1 inch gap at the bottom.  I fitted a 1 inch o/d vent pipe tube protruding 2 inches though you may prefer to make it 1.5 o/d.

John Squeers

<{POST_SNAPBACK}>

 

As usual John your a star!

 

Just to confirm that the pump out steel tube goes into the tank and stops around 1" from the bottom of the tank.

 

Waste pipe then sealed to this (outside the tank) with a large jubilee clip, then same again to the "socket" on the roof. I should be able to run the pipe completely vertical so kinks are avoided. The vent will be going onto the gunnell and also straight pipe work.

 

Thanks again!

[John Orentas]

Stuart.

 

Yes. Spot on.

 

John Squeers

[stuart]

Just got the hose and its now metric - 38mm.

 

I'm looking to try the Vetus no-smell filter onto the vent pipe as well.

 

This will also be 38mm so model NSF38 I think will fit that.

 

http://www.vetus.nl/producten/product_main_87_2.asp

[John Orentas]

Stuart.

 

I have never had problems with smells from the breather, it's the smell when you flush that can sometimes rock you back on your heels.

 

I think it was sound advice from Big col re, using a 38mm breather pipe, I think I might modify mine, I won't bother with the filter though

 

John Squeers

[stuart]

Stuart.

 

I have never had problems with smells from the breather, it's the smell when you flush that can sometimes rock you back on your heels.

 

I think it was sound advice from Big col re, using a 38mm breather pipe, I think I might modify mine, I won't bother with the filter though

 

John Squeers

<{POST_SNAPBACK}>

 

Any idea where to get the skin fittings from. Just tried my local chandler and they looked at me a bit strange!

 

Think I got the YTS boy!

[John Orentas]

Stuart.

 

I'm surprised you have had problems, I have only ever seen one type. Flange (3" dia) mounted with 4 x 4mm csk holes for fixing. Usually chrome plated, the cap has recessed hexagon for removal, overall about 5" long. Not sure if there is a 'standard' vent, there probably is but not critical.

 

John Squeers

[rog guiver]

The shell builder was happy to "build in" the holding tank so, trying to make the C of G full or empty the same, and rather than reducing the width due to the corridor one side we have run the tank under the floor as well (on the corridor side).

 

It may at that point only be four inched deep but stopping the tank about six inches fron the other wall has left little rolling moment between empty and full. An advantage of this setup is that it is reasonably easy to have a pumpout on both sides with a vent and rinse out connection in the roof.

 

The Vent (the same size as the pumpout) pipe also has a bilge blower in the line controlled by a push button on either bathroom. Prior to depressing the lever on the Mansfield a quick press on the blower switch sucks "air" from the tank and hence reduces the pressure, such that no "smellies" enter the bathroom during the operation.

 

Dependant on the wind direction a slight whiff is evident at the stearing end (during the blower operation) but only lasts a second or so but not at any other time.

[stuart]

The shell builder was happy to "build in" the holding tank so, trying to make the C of G full or empty the same, and rather than reducing the width due to the corridor one side we have run the tank under the floor as well (on the corridor side).

 

It may at that point only be four inched deep but stopping the tank about six inches fron the other wall has left little rolling moment between empty and full. An advantage of this setup is that it is reasonably easy to have a pumpout on both sides with a vent and rinse out connection in the roof.

 

The Vent (the same size as the pumpout) pipe also has a bilge blower in the line controlled by a push button on either bathroom. Prior to depressing the lever on the Mansfield a quick press on the blower switch sucks "air" from the tank and hence reduces the pressure, such that no "smellies" enter the bathroom during the operation.

 

Dependant on the wind direction a slight whiff is evident at the stearing end (during the blower operation) but only lasts a second or so but not at any other time.

<{POST_SNAPBACK}>

 

Thanks for the info. What blower do you have? Do these fit straight onto the 38mm pipe?

[Paul Chapman]

Any idea where to get the skin fittings from.  Just tried my local chandler and they looked at me a bit strange!

 

Think I got the YTS boy!

<{POST_SNAPBACK}>

 

My first time on a forum so not sure where I should type and what all these buttons are for. Anyway here goes.

Why do you not consider a composting toilet? No pump outs. No space wasted with holding tanks. Reduced water consumption. I must admit to no direct experiance with them myself but the research I have done on them so far, on the internet, is pretty posetive. I shall be installing one on my nattow-boat when it is built at the start of 2006.

[John Orentas]

Hi Paul.

 

I am surprised you and others are having trouble getting these, you havn't posted the area where you live but there are many chandlers who give a mail order service, I have always found Calcutt boats pretty good.

 

www.calcuttboats.com Tel. 01926 813757

 

Composting toilets had a lot of publicity a couple of years ago, private boaters will, understandably be always be inclined to wait untill such things become accepted in the commercial world before jumping in feet first (that could have been phrased better). Let someone else take the risks first.

 

John Squeers