Nose weight problem reduced.

May 31, 2007
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On collecting my Lunar Quasar 544 2015 from service I found that it was behaving as if it was very light on nose weight which is strange as I normally struggle to get it down to the required 75KG, In fact I specifically asked for the nose weight to be checked on the service to make sure my nose weight scales where reading about what the service garage's was, which was confirmed. so what the heck had changed. I big notice telling me that the water system had been drained was a good clue and on thinking about it I realised that the hot water tank which is situated about half way between axle and the tow hook had been contributing in excess of 20kg of nose weight!
I now drain the water system every time I tow and have a lot less counter balance stuff in the back bathroom.
 
Mar 14, 2005
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Richard_374305805 said:
On collecting my Lunar Quasar 544 2015 from service I found that it was behaving as if it was very light on nose weight which is strange as I normally struggle to get it down to the required 75KG, In fact I specifically asked for the nose weight to be checked on the service to make sure my nose weight scales where reading about what the service garage's was, which was confirmed. so what the heck had changed. I big notice telling me that the water system had been drained was a good clue and on thinking about it I realised that the hot water tank which is situated about half way between axle and the tow hook had been contributing in excess of 20kg of nose weight!
I now drain the water system every time I tow and have a lot less counter balance stuff in the back bathroom.

How much water does your heater hold? It would have to be about 40L to make a 20Kg nose load increase. I think you need to look at what else has been changed.
 
Aug 23, 2009
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Having liquids sloshing around when towing a caravan is not a good idea from a stability point of view. We have always drained down and emptied the both tanks on the toilet prior to any journey,
 
Mar 8, 2017
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I follow Lunar/Thetford advice and empty both the sewage and hot water tank before towing. The sewage tank is then charged with one litre of water and a disinfectant tab. The toilet flush tank is emptied and then refilled with a couple of litres of water.
 
Oct 12, 2013
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I to drain down before leaving a site and leave all the taps open in the caravan to get as much as possible out when towing and so you have no water sitting in the pipes , but just don't forget to shut the taps off before you put the water back on as I found out last time I forgot to turn the shower one off !!

oops :(
 
Jun 22, 2017
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I also found instability while towing when I forgot to drain down the water tank but when I mentioned it, it was rubbished so it’s nice to see some else experience it.
 
May 7, 2012
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I do usually drain down in our Quasar before towing but have not found any real difference either way when towing. It is fairly well forward like with most makes so must contribute something to the nose weight but 20 kg seems to be far too high a figure.
I am not convinced by the sloshing point. If the tank is full then this should not be a problem although if it were part full I can see it would be. As for the toilet I would not want to travel with a tank full or anywhere near that and the header tank does not carry enough to make any difference.
 
Mar 14, 2005
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Martin24 said:
Having liquids sloshing around when towing a caravan is not a good idea from a stability point of view. We have always drained down and emptied the both tanks on the toilet prior to any journey,

As a general point I would agree, but in reality the amount of liquids found in a caravan, and the way they are contained should not cause a problem.

The free surface effect, where liquid can freely cross a surface and collect at one side of a large area was one of the consequential effects involved withe the Sprirt of Free Enterprise ferry disaster in March 1987, but by containing liquids in smaller areas ( i.e in bottles and tanks) the free surface area is reduced and the total mass shift is reduced. Road tankers use internal baffles to prevent the mass movement of liquids upsetting the liquids centre of gravity too much.
 
Mar 14, 2005
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forester08 said:
I also found instability while towing when I forgot to drain down the water tank but when I mentioned it, it was rubbished so it’s nice to see some else experience it.

Hello Forrester,

This is not "rubbishing" you comment, but it does raise my concerns.

If the difference between having your water system filled and empty is the enough to radically affect the stability of your outfit, then I would suggest your outfit even when empty of water is unnerving close to instability, and I would be looking for other reasons why its so marginal.

The adage "the straw that broke the camels back" seems particular apt here.

The transition from stable to instability is not a step change, its progressive, and if only a few kilo's is enough to cause you to change your perception of the outfits stability, it almost certainly means the outfit was marginal before the small weight increase. Being marginal, means that if you were to encounter more extreme towing conditions you may find the outfit is not as controllable as you thought it was.
 
Mar 14, 2005
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Raywood said:
but 20 kg seems to be far too high a figure.
I am not convinced by the sloshing point. If the tank is full then this should not be a problem although if it were part full I can see it would be..

20 Kgs is incorrect. A Truma water heater is usually of 10 litre capacity and since 1 ltr weighs 1Kg the most it can add is 10Kgs. Even so, since my heater is forward in the front corner, I don't travel with it full.
In normal use the boiler is always full because the hot taps run because cold water is being pumped into it, so unless it has purposely been partly drained, it's either full or empty and unlikely to sway.
 
May 31, 2007
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I'll have to re read the manual again as I cant remember ever seeing the advice to drain down water systems before towing. that said emptying the sewage tanks before towing has always been done.
 
Oct 12, 2013
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Richard ,
Why not drain down when youve been away before you tow ? It's only the Flick of a switch and that means next time you go out and set up again on site you have dirty and cold water sitting in your tank , you wouldn't want to be bringing that through the pipes and through the system would you ?
Craig . :huh:
 
Mar 14, 2005
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Richard_374305805 said:
I cant remember ever seeing the advice to drain down water systems before towing. .

Probably not in the instructions but why carry an extra 10 kilos when not necessary. Also, a few years ago I left my van on site for three weeks whilst I went home. On my return to the van, the first bowl of water drawn off smelt foul.
 
Nov 16, 2015
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We dont have an onboard water tank , but fill the water Heater ( riighthand side 3 feet back from the front .) on leaving home, and heating it.As we require a bit of nose weight on the van. I liketo be heavier than light now, I finf the van tows better.
 
Jun 22, 2017
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What can I say? Ever since travelling with an empty tank the towing has been very stable including our winter escape to southern Spain at around 3,400 miles. Could it be some drivers are more alert to slight changes to the tow vehicle behaviour? For example I am a retired mechanic so I still drive as if I am road testing a vehicle in that I am always aware of vibrations, rattles unusual steering actions etc.
 
Jun 20, 2005
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As a very young dog my caravan mentor, long departed, always made us empty ALL water tanks before towing. This I still do and have never had any upsets at all. Why would anyone want to tow with full water tanks :silly:
 
May 7, 2012
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Dustydog said:
As a very young dog my caravan mentor, long departed, always made us empty ALL water tanks before towing. This I still do and have never had any upsets at all. Why would anyone want to tow with full water tanks :silly:

If nothing else you are using fuel to tow the weight of the water, although I cannot say I have noticed any real difference in consumption either way.
 
Nov 11, 2009
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bertieboy1 said:
Prof,
1Ltr of water weighs 1Kg not 2 Kgs.

I think that Prof was probably assuming that as the heater tank was not sited on the hitch and would be some feet away from the hitch then you would need a larger amount of water change to bring about such a change in nose weight. It's all to do with the lever arm and moments of force/weight.
 
Mar 14, 2005
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Hello Bertie,

I never suggested a litre of water would weigh more than 1kg, I am very much aware of the sg of water, I have used that fact on many occasions.

Clive is right. Richard had already told us the heater was situated in front of the axle, but logically it would be located within the extend of the body and not as far forward as the hitch. In practice it would be likely to be between 1/3/ and 1/2 half the distance of the axle to the hitch.

I do admit I made one assumption, and that was Richards assertion the water system had made the difference, and I assumed he was referring to the water heater, and if that is the case , just the water content on the heater could not produce the nose load difference he quoted. Hence my comment about how big his heater was.

However If his caravan has an inboard tank situated ahead of the axle. then that would certainly increase the effect on the nose load.
 

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