Travel with water tank full or empty?

[MandM]

We have a couple of 10 litre water bottles that we use when travelling. Leaving the on board fresh water tank empty between stops. While in France we were advised by a fellow UK MH driver that he travels with the tank full for better stability. We also watched a large Concord owner (German) fill his two huge water tanks before departing....

Now this did not seem a sensible option to me. Less weight seemed to be the way to go especially as it might compromise the vehicle weight limit.

Thoughts please?

 

[PeteH]

Half full for me. Use to carry a bit more than that until I found I could stash away a further 12 bottles of real ale between the fresh waster tank and the rear of the van......Have to keep the weight down as both the van and I grow old and get heavier together!!

A man of obvious good taste!.

Pete

 

[PeteH]

In my book of words it says not to run around with a full tank & part of the reasons being the tank is quite high up under the bench seat. I have done it once for wilding and I could feel a slight wallow! A bad half to quarter is my usual if I suspect no water supply.

When (Here we go again) "I was a yung un". I had to do Naval Architecture for my Marine Engineering Qualifications. One subject matter concerned "Free surface effect", basically IF you have "slack" tanks, you will feel the "roll" more as the Wedge of water (mass) generated by movement, in the tank has a cumulative effect on stability, (That`s the simple version). So empty or full ("pressed up" as we used to say) is the best condition for stability.

BTW. "free surface effect" ( the movement of the water on an open deck) is what caused the Herald of Free Enterprise to Turn "Turtle" (Capsize) with such a great loss of life back on the 6th of March 1987. It you want a demonstration, try putting water on (say) a tea tray with deep sides and walking without spilling, it is nigh on impossible!.

Pete

 

[Minxy]

PeteH - I too was aware of the problem of half-full tanks (although I didn't know the technical term) which is why we try to keep ours topped up if we can which is easier than emptying it every time you want to drive somewhere! I'm surprised that nowadays they don't fit 'baffles' of some sort to prevent the water moving completely from one side to the other and therefore reduce the effect of the water sloshing around in the tank but I suppose it would be more costly to manufacture and also make it more difficult to clean.

 

[PeteH]

PeteH - I too was aware of the problem of half-full tanks (although I didn't know the technical term) which is why we try to keep ours topped up if we can which is easier than emptying it every time you want to drive somewhere! I'm surprised that nowadays they don't fit 'baffles' of some sort to prevent the water moving completely from one side to the other and therefore reduce the effect of the water sloshing around in the tank but I suppose it would be more costly to manufacture and also make it more difficult to clean.

It`s the same effect that can happen with Road Tankers, and why the vast majority do have baffles. My Pal, who was a lifetime truck driver, tell`s the story of when he was in the RAF on flight refuelling, he came to cross the runway one day and was stopped because of aircraft movements, the NEW tanker he was driving stopped OK, and then several seconds later MOVED FORWARD on it`s own!!, pushing him (with handbrake on) over the "line". The MP`s (snowdrops!) started an investigation and it was found that the NEW tanker had NOT been fitted with baffles which caused the mass of liquid to Surge forward having surged back and the kinetic energy was sufficient to overcome the friction of brakes and tyres!.

Pete

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[Old Soldier]

Without wishing to cause another argument I can't believe travelling with only half a tank is going to cause that much of a problem. After all the tank size in my case is only 80 ltrs, (18 Galls) about the same as my fuel tank and I don't keep that full (unfortunately!!). When I drove Green Goddess's in the Army we had 500 gallon in un-baffled tanks on a 3 ton Chassis and THEY were a real problem.

 

[Forestboy]

Oh come on really !!
Theres no way 50 litres of water slopping atound in an onboard tank is going to cause a 3500 kg motorhome to roll over.

A super tanker with more weight above than below or a fire engine with a big tank high up yes.
But 50 ltrs is the weight of a very small person or a big dog.

 

[bigtwin]

Wow, you've got some strong bladders there!!! Respect!!!

Ahh, but their strategy is not to overfill their bladders with tea!

Ian

 

[Old Soldier]

Hi again. Just reading through this thread again and I bet the O P @MandM wished he'd never asked for our thoughts!! Seems he has lost the will to live, or at least answer and take part in the conversation!!
Another thought I had about carrying surplus liquids in the van was that when I leave the pub after drinking a good few pints of real ale, I can hear and feel it slopping around, moving from side to side in me belly. Now if I thought that was going to make the van unstable I would think twice about driving it!!.!!!!

 

[Larrynwin]

Hi again. Just reading through this thread again and I bet the O P @MandM wished he'd never asked for our thoughts!! Seems he has lost the will to live, or at least answer and take part in the conversation!!
Another thought I had about carrying surplus liquids in the van was that when I leave the pub after drinking a good few pints of real ale, I can hear and feel it slopping around, moving from side to side in me belly. Now if I thought that was going to make the van unstable I would think twice about driving it!!.!!!!

Always makes me unstable, bloody white lines not straight when walking home from pub

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[Glandwr]

I USUALLY travel full BUT don't if I expect a windy journey. Ours can be a pig in the wind especially on a motorway. The tank is big and to the rear of the back axle. Part empty there is more of the weight on the front axle and the effect of wind is noticeably less.

Dick

 

[Minxy]

Oh come on really !!
Theres no way 50 litres of water slopping atound in an onboard tank is going to cause a 3500 kg motorhome to roll over.

A super tanker with more weight above than below or a fire engine with a big tank high up yes.
But 50 ltrs is the weight of a very small person or a big dog.

Who said anything about rolling over? The effect of it moving around from side to side can definitely be noticed ... depending on where the tank is located/size/amount of water in it, it can make it a bit disconcerting when you 'feel' the movement!

 

[Old Soldier]

the effect of wind is noticeably less.

Dick

I don't notice the wind too much, more a problem for Les than me.....

 

[PeteH]

There is no way that (say) 80 litre of water is going to affect the stability of a Motor-home in any significant manner. I was actually replying to Minxy. Who had noticed an effect and attempting to explain WHY such an effect was present. It will be less noticeable IF the tank is filled to the brim, which may not be the best option for other reasons including increased pressure on fittings etc. In practical terms "you pays your money"?.

I often travel with little or no water, because of weight considerations on 3500kg limit. On the other hand My old R-V never went out unless it was FULL, (40+ US gallons) and the Grey / Black empty, but then I had a 3tonne Payload!.

Pete

 

[OG1]

Just enough water in the system to keep the pressure up and a small 5 litre container for that tea and coffee when we stop. empty the grey water and toilet system. fresh water tank is 80 litres, Waste 80 litres and water heater is 10 litres. that may work out to 160 Kg or 352 lb.
We never run with a full tank of fuel and work out our distance to the next stop over. Less weight may help the MPG. not forgetting the pay load.

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[ojibway]

If travelling in France we always leave with a full tank plus two or three 5lt bottles of water.
But we are cautious about filling on aires as the taps can be disgusting from people sticking them into their toilet cassettes to rinse them or having dirty hands from handling the cassette and then the tap.
I have sometimes sprayed a tap with disinfectant before using it.
In Gruissan they put the fresh water tap at head level with a metal cage around it to prevent people rinsing cassettes!!

 

[Xabia]

When I bought my first Hymer from the factory in Bad Waldsee the tank was filled as they said that the vehicle rode much better in that condition.

 

[Nirvanauk]

Just enough water in the system to keep the pressure up and a small 5 litre container for that tea and coffee when we stop. empty the grey water and toilet system. fresh water tank is 80 litres, Waste 80 litres and water heater is 10 litres. that may work out to 160 Kg or 352 lb.
We never run with a full tank of fuel and work out our distance to the next stop over. Less weight may help the MPG. not forgetting the pay load.

Sounds different.

 

[maison]

Just enough water in the system to keep the pressure up and a small 5 litre container for that tea and coffee when we stop. empty the grey water and toilet system. fresh water tank is 80 litres, Waste 80 litres and water heater is 10 litres. that may work out to 160 Kg or 352 lb.
We never run with a full tank of fuel and work out our distance to the next stop over. Less weight may help the MPG. not forgetting the pay load.

Would not disagree with much of this but we.........

always have the toilet system ready for use. No separate header tank so water comes from fresh water tank.

Always fill the fuel tank when we can buy fuel at a good price. The saving by running at low fuel levels may be totally negated by having to top up at expensive filling stations when running low.

 

[MandM]

Has the OP recovered from the enthusiasm of the responses to the original question?

It has been quite illuminating, there seem to be a few partisan groups. Re: running full or half/empty.

We are now on our 3rd trip to Europe. Tried to suck it and see. We seem to have settled for half a tank from home until reaching Calais. Fill up to the top and head south. We seem to average around 25 litres a day when wild or semi wild. So we can go for four days before needing to fill up again. Though like the fuel tank - when the water gauge reads half - we start to look for a refill.

As a boat owner we are used to having a 800 litre fresh water (white) lasts about 2 weeks. A 450 litre pumpout poo tank, (Black) which lasts us about 6 weeks. Using the boaters mantra if its yellow - let it mellow but if its brown - flush it down. Other waste (Brown) water goes straight over the side from sink, washing machine and shower. We use eco friendly products.

On the boat we use the first get wet / then get soapy / then wash off. Turning the water off between stages. We do the same in the van and so we can have a shower every other day.

Regards

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[MandM]

Hi again. Just reading through this thread again and I bet the O P @MandM wished he'd never asked for our thoughts!! Seems he has lost the will to live, or at least answer and take part in the conversation!!
Another thought I had about carrying surplus liquids in the van was that when I leave the pub after drinking a good few pints of real ale, I can hear and feel it slopping around, moving from side to side in me belly. Now if I thought that was going to make the van unstable I would think twice about driving it!!.!!!!

I have had plenty of food for thought. The size of tank is all important as is the personal consumption rate. However, from trial and error - the bottom line is there is no single answer. Users personal preferences tempered by any axel weight restrictions.

Since I posted the original posting - we have been distracted by a personal illness. Everything is now fine and normal service has been resumed. Curtsey of the worlds finest working in the National Health Service. Through the skills of an Indian heart Surgeon, a Polish anaesthetist and several very attractive eastern European nurses. Who in an un-clinical way improved my heart rate quite dramatically.

Currently in Benidorm enjoying sun/snow/wind/rain/hail and beer at 1.5 euro a pint.

Regards

 

[davidathomas42]

Reading the original posts I have a question.

Do Caravans not have any built in water or waste tanks then? I bought a Motorhome because I like the idea of off grid self sufficient (I did want a proper off grid Toyota Landcruiser with roof tent etc originally but the missis said no )

So we opted for the Swift Escape which is better for our current lives.

But yea on sites I see caravans with all sorts of contraptions plugged in the sides. Is that Water. Waste and Black tanks that have to be filled on arrival? Seems a hell of a pain! Guess it gives more living space if so but the way our motorhome is kitted out everything is under slung or hidden anyway so cant be a huge difference I would have thought.

 

[Clarky]

Caravans don't usually have any sort of on-board tanks although some of the larger ones can have a smallish fresh tank which would be empty when travelling.
Weight and tow hitch weight are all important when towing so even the Truma/Alde boiler are usually drained when leaving sites.
Water is fetched in a roll along container with a submersible pump connected into a socket in the side of the van, pumping the water into another socket in the side. Grey waste goes into a wheeled container that is taken to the service point to empty.

All of that faffing around is why you would be on your second beer before the tuggers have even thought about putting the kettle on without even thinking about fitting awnings.
Watching tuggers set up on site is a national spectator sport.

Richard.

 

[funflair]

Reading the original posts I have a question.

Do Caravans not have any built in water or waste tanks then? I bought a Motorhome because I like the idea of off grid self sufficient (I did want a proper off grid Toyota Landcruiser with roof tent etc originally but the missis said no )

So we opted for the Swift Escape which is better for our current lives.

But yea on sites I see caravans with all sorts of contraptions plugged in the sides. Is that Water. Waste and Black tanks that have to be filled on arrival? Seems a hell of a pain! Guess it gives more living space if so but the way our motorhome is kitted out everything is under slung or hidden anyway so cant be a huge difference I would have thought.

Some caravans have water tank but I don't think any have a grey waste tank.

Most will have an aquaroll or water barrel for fresh water and a plastic grey water container to trundle to the drain with, toilet, black waste is the same as motorhomes other than those with black tank.

Martin

 

[funflair]

Caravans don't usually have any sort of on-board tanks although some of the larger ones can have a smallish fresh tank which would be empty when travelling.
Weight and tow hitch weight are all important when towing so even the Truma/Alde boiler are usually drained when leaving sites.
Water is fetched in a roll along container with a submersible pump connected into a socket in the side of the van, pumping the water into another socket in the side. Grey waste goes into a wheeled container that is taken to the service point to empty.

All of that faffing around is why you would be on your second beer before the tuggers have even thought about putting the kettle on without even thinking about fitting awnings.
Watching tuggers set up on site is a national spectator sport.

Richard.

We never emptied our onboard water tank or water heater to travel, but yes there is more faffing about but usually just the unhitching and winding legs down, saying that some people faff around levelling a motorhome.

Martin

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[davidathomas42]

All of that faffing around is why you would be on your second beer before the tuggers have even thought about putting the kettle on without even thinking about fitting awnings.
Watching tuggers set up on site is a national spectator sport.

Richard.

My god so happy I hate caravans and went for a motorhome then. That all sounds way to much hassle.

I like the idea of the family having all that room in the rear travel seats over been strapped in a Mondeo crossing Europe and also the ability to cook a bacon sandwich while driving (legally no but you could )

Each to there own though I guess. If we all liked the same things life would be very dull.

 

[Bobby22]

Just for the record my new van doesn't allow me to travel with a full tank. It has a lever i must set which drains the tank to 20 litres.

 

[Clarky]

We never emptied our onboard water tank or water heater to travel, but yes there is more faffing about but usually just the unhitching and winding legs down, saying that some people faff around levelling a motorhome.

Martin

Problem with the onboard tanks we had on caravans was that they were right at the front of the van which was good for weight distribution but terrible for keeping the nose weight within limits.

Richard.

 

[Clarky]

Just for the record my new van doesn't allow me to travel with a full tank. It has a lever i must set which drains the tank to 20 litres.

Think that depends on the van and the available payload. We all know that many vans sold as under 3500kg have a terrible payload available.
In our van, upgraded to leave us plenty of spare payload, we often travel with full 180 litre tanks.

Richard.

 

[Kingham]

Reading the original posts I have a question.

Do Caravans not have any built in water or waste tanks then?.

My last caravan had an onboard fresh water tank, under the front bunk and had to be drained down before travelling to keep the nose weight correct.
It was a faff filling up, with two levers which had to be set according to one of three options... 1) Filling the onboard tank from the Aquaroll,
2) Sending water from the onboard tank to the taps 3) Bypassing the onboard tank, with water from Aquaroll going straight to taps.

I've never seen a grey waste tank built in to a caravan.

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[dulvil]

Do you travel with an empty or full diesel tank?