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26/05/2010 at 5:07 pm #9339mhardmanMember
From the point of view of my understanding of the physics :
The trailer will be stable when it’s centre of gravity is in front of the axle. When it’s centre of gravity is in front of the axle, you will get some nose weight. This is the reason for wanting nose weight : it ensures that the centre of gravity is forward and you will get stable towing without snaking.
You don’t want too much nose weight though, as this will make the car handle badly and sag at the rear.
Wind resistance of the boat / trailer complicates things but the effect is like moving the centre of gravity of the boat rearwards. That’s why the trailer can be perfectly stable at 55mph but not at 70mph.
So usually you go for enough nose weight to get stable towing at the max speed you want to go at. 25kg is a good start.
Heavy weights should be kept near the axle for best towing (minimum pendulum effect) and then fine tuned to get the nose weight.
“2) Noseweight. This is the amount of force the trailer exerts on the towbar of the car. Too much and steering becomes vague and grip for front wheel drives is compromised. This is where I would disagree with some comments from other contributors. If you put the heavy kit in the boot of the car you increase the noseweight effect. I would put heavy gear in the rear of the boat to offset noseweight. The caravanning club should have some advice on noseweight on their website.”27/05/2010 at 10:21 am #9342RichardPMember
There’s a “Towing Code” that the various caravaning associations and DOT put together which you can find here:
General advice for caravans in this code is even distribution of weight with 7% of the all-up caravan mass being put onto the hitch. Based on the earlier estimation of 300-350kg for a Wayfarer and gear, that would suggest you’d ‘feel’ 21-24.5kg on the hitch (so in line with mharman’s advice of 25kg). There’s an illustration on p15 of the guide on how to measure this with a set of bathroom scales and a block of wood.
The advice on getting your all-up weight is to use a public weighbridge. There’s a directory of these here by county
http://www.chrishodgetrucks.co.uk/pageweighbridge/weighbridgeshome.htm Sounds like you can expect to pay anthing from £5 to £30 for this service and some piece of mind.27/05/2010 at 12:43 pm #9343SwiebertjeParticipant
There’s an illustration on p15 of the guide on how to measure this with a set of bathroom scales and a block of wood.
But then you would have to take a bathroom scale along. Just imagine the troubles I would get myself in to if my captain (to whom I am married) would demand me to step on it……
For less then a tenner you can still get one of those small 50kg brass fishing scales (the type with a spring and a hook). They store easy in your box-o-junk that we all seem to carry along. Today there are also electronic versions available too but they seem to be more expensive then the classic, spring operated types. And the batteries are always dead when you need it. But if you insist, the electronic fishing scales are available from just over a tenner. (Search for fishing supply shops on the Internet).
Maybe I am not so accurate as the previous posters, if the tow ball weight is somewhere between 25 and 50 kg its fine for me. I know that I can easily lift the hitch with one arm if its weight it is around 25 kg. If it is 50 kg I can only just manage to lift it with one arm. So, if the weight is between easy and hard to lift it is OK. For reference: A bag of cement in a DIY center is 25 kg, try to lift it and then try to lift two if you happen to be there.27/05/2010 at 1:08 pm #9344HoggyMember
Thanks chaps for your recent replies, I looked at he caravan towing sight and it was very helpful. I will not be getting the bathroom scales out in front of my wife for the same reasons as Swiebertje. I guess it will be Under cover of darkness with a head torch 😆
Geoff.30/05/2010 at 6:33 am #9352Adrian PeryMember
There is a good article starting on page 30 of the July edition of Practical Boat Owner that sets out things quite clearly.08/06/2010 at 12:22 pm #9379HoggyMember
Thanks Adrian I will look at the article If I can find a copy in the news agent, thanks again.
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