Ever wondered about how something on your caravan works, but couldn’t ask because it seemed like one of those simple questions you should have known the answer to all along? Well, wonder no longer. Here you’ll find the answer to some of those questions about your caravan that have always been bugging you. We will be working right through the alphabet, paying particular regard to safety. And whether you are new to the hobby or an old hand, we bet there will be something here that you didn’t know.
Click Here for A to I

J  IS FOR
JACKS
Most makers do not supply jacks with their caravans, but scissor and hydraulic jacks are available at most motoring stores. When buying a jack, ensure that it is has the right capacity and sufficient height of lift. Unless you are using a purpose-designed caravan jack, the jack should be placed under the axle tube as close as possible to the adjacent chassis member. The opposite wheel should be chocked, and the steadies lowered to aid stability. Never use steadies as jacks.

K  IS FOR
KERBWEIGHT
In the UK, the Construction and Use Regulations 1986 define kerbweight as the weight of the towcar with a full fuel tank, liquids (lubricants, oils and water) adequate for normal operation, plus its standard set of tools and equipment, but not the weight of the driver, other occupants or load. The EU Directive 95/48/EC defines kerbweight as the vehicle’s weight when it leaves the maker with its fuel tank 90 percent full, all necessary fluids for normal operation, nominal driver weight of 68kg and 7kg of luggage. Both definitions are legally acceptable, but to be on the safe side you might want to stick to the UK definition.

L  IS FOR
LIQUEFIED PETROLEUM GAS
(See also ‘butane’ and ‘propane’)
Caravans use liquefied petroleum gas – butane or propane. Both become liquid under pressure but change back to gas upon release from the cylinder. LPG cylinders should never be stored on their sides because the liquefied gas will touch the valve. If a leak occurs the gas expands to 200 times its volume, leading to a risk of explosion.

LOADING
The way the caravan and car are loaded can affect the handling of the outfit. Heavy loads should be placed over, or immediately in front of, the axle. The load can also be balanced by placing equivalent loads immediately behind the axle. Medium-weight items should be placed towards the front of the van, under seats and in floor cupboards. Only light items should be placed in the roof lockers. Medium and heavy items should never be placed at the rear of the van, since they can cause instability. For the same reason, make sure that water and toilet tanks are empty before towing. Remember, too, that the caravan’s noseweight, as stated by the manufacturer (or by the towcar manual – whichever is less), must not be exceeded.

M  IS FOR
MIRO
MiRO stands for Mass in Running Order and refers to the van’s weight, with all factory-fitted equipment, when it leaves the factory. MiRO replaces the old terms ‘ex-works weight’ and ‘unladen weight’.

MTPLM
Maximum Technically Permissible Laden Mass is the modern version of Gross Vehicle Weight. It refers to the maximum weight that the caravan chassis can take, as stated by the chassis manufacturer. For inexperienced drivers, the MTPLM of the caravan should not exceed 85 percent of the towcar’s kerbweight, thus ensuring sufficient power reserves to cope with circumstances such as hill starts.

MICROSWITCH WATER SYSTEM
At the base of the taps and the shower control system are microswitches. When the control is turned on, the switch allows electricity to flow to the water pump. The disadvantage of the microswitch system is that the switches sometime fail and have to be replaced. But unlike the pressure switch system, microswitches are not affected by a drop in voltage.

N  IS FOR
NOSEWEIGHT
A caravan’s noseweight is the weight that it applies to the towball. The maximum noseweight must not be exceeded. This tends to range from 50-100kg but you should really work to either the caravan chassis or tow vehicle manufacturer’s figure – whichever is less. Generally speaking, the heavier the noseweight the better the caravan will tow. But finding the right noseweight for optimum towing performance is a matter of trial and error. One way of calculating noseweight is to take seven percent of the MTPLM, or you could alternatively use a noseweight gauge.

O  IS FOR
OVERTAKING
Because of the outfit’s increased length and the difficulty of accelerating rapidly, overtaking requires the driver to plan further ahead than when driving a car solo. Allow plenty of time for the manoeuvre and signal your intentions well in advance. Be prepared to abandon the manoeuvre if circumstances change. Signal your intentions to the vehicle you have overtaken before pulling back into line and always allow plenty of room before doing so. Remember that caravans cannot use the outside lane of dual carriageways or motorways with three or more lanes, except where there are roadworks or signs to the contrary. Finally, never overtake other vehicles when travelling downhill, or you could ‘snake’.

P  IS FOR
PRESSURE SWITCH WATER SYSTEM
The pressure switch water system is the alternative to the microswitch system. Here, a pressure switch in the waterline detects a drop in pressure when a tap is opened, instantly allowing current to flow to the water pump. One disadvantage of the system is that even a tiny leak or a tap left slightly open will cause a drop in pressure, which will, in turn, cause the switch to activate the pump. Another disadvantage is that the switch is susceptible to a drop in the leisure battery’s voltage, although this problem can often be solved by adjusting the switch via the knob on top of it.

PROPANE
Propane is the second of the two LPG gases used in caravans. While it has a slightly lower calorific value than butane, propane can be used at temperatures of -40ÞC. You will get slightly less propane in your cylinder than you would butane, but since it can be used at any temperature, many all-season caravanners will use only propane.

Q  IS FOR
QUESTIONS
Even experienced caravanners need to ask questions. That’s where we come in. Email or write to us, or call the Practical Caravan Hotline on 020 8267 5757, and we’ll get back to you within three working days.

R  IS FOR
REVERSED POLARITY
In the UK, the live wire of a cable takes the electricity to the appliance, while the return cable takes it back to earth. When the electricity flows in the opposite way to this, it is known as reversed polarity. Some appliances have on/off switches fitted to the live wire, so although the appliance might appear to be switched off, it could actually be alive – although this is more of a problem with older caravans. On the Continent, reversed polarity is much more common. To overcome the problem, you should carry a short lead in which the live and return cables are changed over to ensure the the polarity is correct when the electricity reaches the appliance. This is a basic DIY job that was covered in more detail on p121 of the June 2002 issue of Practical Caravan (to order back issues call 08456 777812).

S  IS FOR
SEASONAL PITCHES
Many caravan parks offer pitches that can be hired by the season. The owner leaves their caravan there and can visit it whenever they like. This type of pitch is ideal for caravanners who find hitching-up and towing difficult because of age or infirmity, or those whose job means that they cannot plan their caravanning in advance.

SNAKING
Snaking is when the caravan sways from side to side during towing – it is a real-life example of the tail wagging the dog. It often happens to badly matched or poorly loaded outfits when towing at speed (especially downhill), or when passing or being passed by large vehicles. Once it starts, it is hard to stop. research by Bath University confirms the view that trying to accelerate out of snake will only make it worse. They say that you should lift your foot off the accelerator and allow the engine to act as its own brake. At the same time, loosen your grip on the steering wheel, and allow the steering to right itself.

STABILISERS
Stabilisers are not a legal requirement and many caravanners do not use them at all, but they do improve the towing characteristics of a well-matched outfit by dampening the swaying and pitching movement of the van as it articulates. Most stabilisers are friction devices and come in two forms: those that are part of the coupling (such as the AKS, Winterhoff and SSK) and those comprising a blade spring and friction disks such as the Bulldog. The gas-strut operated Straightliner, is the exception.

T  IS FOR
TORQUE
Torque refers to the power of an engine. You will need a car that has a lot of torque low in the rev range to get the caravan moving in first place; once it is moving, it will need less torque to keep going. When looking for a towcar, be it a petrol or diesel engine, look for one that produces its maximum torque at comparatively low revs, say under 2500rpm.

TRAIN WEIGHT
Short for gross train weight or maximum train weight, this is the maximum weight that a car can tow (its own weight plus any weight of the van) on the road, as stated by the manufacturer.

U  IS FOR
USER PAYLOAD
The user payload is the weight that you may add to your caravan before it exceeds its maximum technically permissible laden mass – in other words the amount of luggage and other items you can load it with. It is found by subtracting the mass in running order (MiRO) – the caravan’s unladen mass – from its MTPLM.

V  IS FOR
VIN
Since 1992, a unique vehicle identification number has been allocated to every new caravan. The VIN is etched on the van’s windows and is stamped on the chassis. Since 1997, all vans will also have had two electronic tags containing the VIN concealed within them during construction. This information is recorded by CRiS – the Caravan Registration and Identification Scheme (tel 01722 411430). For a small fee, buyers can check with CRiS to see if a van has any finance outstanding on it, or whether it has been reported stolen. However, since the scheme is voluntary it can never be completely accurate.

W  IS FOR
WATER PUMPS
Submersible pumps fit into the water container and push the water into the van. They rarely give trouble but since they are so cheap (around £25) they are easily replaced if they fail. Diaphragm pumps pull the water from the water container. They are expensive, but relatively easy to service and can run dry without damage. The noise they make during operation can be intrusive, and this, combined with the price, makes them less popular with caravanners.

XYZ  IS FOR
All the rest. For everything else you could ever want to know about caravanning, pick up Practical Caravan every month, and you’ll be an expert in no time. Happy caravanning!