Glossary of Terms

Caravan and Motorhome Terms Glossary

12-volt DC: A motorhome’s primary electrical system, in which 12-volt direct current is supplied by onboard batteries to run the lights, stereo, radio, water pump, heater fan and other equipment. Helps to make the motorhome self contained.

A Class: A motorhome built on a base vehicle from the chassis up.

Air Rides: Proprietary name for spring assisters fitted to the rear axle, said to improve handling characteristics of the motorhome.

Aire De Service: Term used to describe independent motorhome service points which usually have the following facilities:- CDP, Fresh Water tap, Mains hookup.

Awning: A canvas extension over a window or patio area of a Caravan.

Axle Weight: The amount of weight carried by a single axle and the amount of weight transmitted to the road by one axle.

Base Vehicle: The vehicle - usually either a panel van or a chassis cab - that provides the base for a motorhome conversion. Leading base vehicle suppliers include Citreon, Fiat, Ford, Iveco, Mercedes, Peugeot, Renault & Volkswagen.

Blown Air Heating: A method of heating the living quarters of a motorhome. Common trade names are Carver, Domestic, Domestic, Truma and Propex.

Breakaway System: An emergency device designed to stop the towed vehicle if it were to dislodge from the motorhome. Some of these devices are integrated into the supplemental braking system, while some are sold as accessories.

British Thermal Unit (BTU): The quantity of heat needed to raise the temperature of one pound of water by one degree Fahrenheit. Air conditioners and furnaces are rated in Btus.

Caps (front, end, roof): Refers to a family of molded body panels used on many of today’s motorhomes. Often they are constructed of fiberglass, but in some cases caps or other body panel may be composed of ABS, RTM, RIM or SMC construction. Sometimes they are in upper and lower sections; hence the term “roof cap”.

Captain’s Chairs: The driver’s and passenger’s seats at the front, or cockpit, of a motorhome. The chairs are often swivel to face the living area.

Cassette Toilet: A type of toilet where the waste is held in a removable container sometimes known as a cassette, which you carry to a Chemical Disposal Point on a campsite / Aire De Service to empty.

CC:  Camping Club.

CCC:  Camping and Caravanning Club.

CDP: Chemical Disposal Point, a drainage area used for the disposal of toilet waste (Black water).

Chassis: The rectangular steel frame that holds the engine, running gear, and steering and suspension systems and on which the body section of the motorhome is mounted. In coachbuilt motorhomes, the chassis includes these components as well as a cab section.

Chassis Battery: The battery used for starting the motorhome and powering the 12-volt DC automotive components of the drive-train. Also called SLI (starting/lights/ignition) battery.

Cockpit (aka CAB): The driver/passenger area in the front of the motorhome, where many of the motorhome’s system and instrument controls are located.

Cold Cranking Amperes (CCA): The number of amps available to start an engine when the ambient temperature is cold. Used for rating SLI battery capacity.

Converter/Charger: When the motorhome is connected to an AC power outlet, this electronic device automatically converts 240 volts AC to 12 volts DC to run 12-volt equipment. At the same time, can recharge the 12-volt batteries.

Crowned Roof: A motorhome roof that is curved, rather than flat. A curved roof has the potential to be stronger and provide for better water runoff.

Curb Weight: The weight of the vehicle empty (without payload and driver) but including engine fuel, coolant, engine tools, spare tyre, and all other standard equipment. Curb weight is determined without water in tanks or water heater and with empty LP-Gas containers.

Delamination: In coach construction, a failure of the adhesive bond line, or of one of the individual components, within a laminated assembly (sidewall, roof, floor, etc.). Modern construction adhesives have reduced this problem.

Diesel Engine: Diesel powers many long and heavy type A motorhomes and bus conversions due to torque and fuel efficiency. More powerful and durable than petrol engines, it is very common to travel over 350,000 kilometres from a diesel without any repairs is normal.

Far Side: The side of a motorhome/caravan/bus that is furthest from the curb.

Fit and Finish: Generally refers to the level of quality in which a motorhome is constructed. A manufacturer who utilises advanced manufacturing processes will be able to build components to smaller “tolerances”; the result is a higher level of fit and finish. The consumer will notice that everything fits well and has a quality level of finish - upholstery, cabinets, drivability.

Full-Timer: A person who travels and lives in a motorhome for most of the year.

Gross Axle Weight Rating: According to the chassis manufacturer, the maximum allowable weight of a single-axle assembly as measured where the tyres meet the ground. The GAWR is established by considering each of its components (tyres, wheels, springs, axel) and rating the axle on its weakest link. The GAWR assumes that the load is equal on each side.

Gross Combination Weight Rating (GCWR): The maximum allowable combined weight of the motorhome and attached towed vehicle and everything in and on them, as designated by the manufacturer.

Gross Vehicle Weight Rating (GVWR): The weight specified by the chassis manufacturer as the maximum loaded weight of the vehicle (including driver, passengers, liquids, and cargo). Usually posted on the inside wall near the driver’s seat.

Holding Tanks: Tanks that collect black water (toilet waste) and grey water (sink, shower, lavatory). Also, the freshwater tank, which supplies the water used by the motorhome’s occupants. Holding tank capacity is one of the factors in how long a motorhome can be used without hookups.

Hookups: Facilities, such as those at a campground, for connecting for connecting the motorhome to 240-volt AC power and water and sewer service. Can include cable TV and telephone connections as well.

Leisure Battery(ies): The deep-cycle battery(ies) that powers the motorhome’s 12-volt DC electrical system, separate from the chassis. Powers the coach lights, water pump, furnace blower, vent fans, stereo, refrigerator (in 12-volt mode) and other house equipment. The number and rating of batteries used depends on the motorhome’s battery compartment size and the motorhomer’s camping tendencies. Caravaners who frequently use electric hookups in campgrounds may not need to carry as many house batteries.

LPG (Liquefied Petroleum Gas): Is the generic name for mixtures of hydrocarbons (mainly propane and butane). LPG is colorless and odorless so a sulphur based chemical (ethyl mercaptan) is added to give it a smell like rotten cabbage so that even a small leak can be easily detected. Stored in cylinders LPG burns readily in air and has energy content similar to petrol, which make it an excellent fuel for heating and cooking.

Inverter: A device that converts 12-volt direct current to 240-volt alternating current.

Laminate: In motorhome/caravan/coach construction, an object (panel) constructed of various flat layers attached (usually bonded) together to act as one homogenous structure; a components in such an assembly. Used for motorhome’s wall, floor and roof assemblies. Laminated construction techniques are often used in higher-end motorhome’s.

Leveling System: Portable or built-in fixtures and associated controls that level the motorhome while parked. Some motorhome’s have a 12-volt automatic leveling system using jacks underneath the chassis; the system controls are near the driver’s seat. Owners of earlier models may simply insert wood or plastic blocks underneath the tyres to elevate the vehicle. Leveling is one of the first tasks after settling in at the campsite, and can affect refrigerator performance, water drains and the stability of various items.

Motorhome: A self-propelled, completely self-contained vehicle that contains all the conveniences of a home, including cooking, sleeping, and permanent sanitary facilities and in which the driver’s area is accessible in a walking positions from the living quarters.

Near-Side: The side of a motorhome/caravan/bus that is closest to the curb.

Net Carrying Capacity (NCC), or payload:  The maximum weight , including all personal belongings, food, fresh water, LP-Gas, tools, dealer-installed accessories and occupants that can be added without exceeding the GVWR> Can be computed by subtracting the empty weight of the vehicle from the GVWR.

OEM:  Abbreviation for original equipment manufacturer.

Overcab Bed: A sleeping area that spans the driver’s and passenger’s seats in many Coachbuilt motorhomes. Can be used for storage when not in use.

Pass-Through Storage: Exterior compartments that span the full width of the motorhome, accessible from either side.

Pull-Through Site (as opposed to back-in-site): A camping space that only requires the driver to drive through to access a camping spot, and to just pull forward again when exiting the spot. Back-in sites can be difficult to maneuver a large motorhome into, and they usually require unhitching of vehicles towed four wheels down.

Safari Room: An awning that has panels which can be affixed to create a complete room protected on all sides.

Slideout: An addition to a motorhome that extends up to 1 metre beyond the normal outside walls to enlarge the living, sleeping, dining or gallery areas. Operated when the vehicle is stationary, usually at the touch of a button.

SOG: A type of toilet where toilet chemicals are not used, instead utlising a forced air system.

Subfloor: The panels that generally comprise the floor of a motorhome’s storage area, the basement floor.

Supplementary Braking System: A separate functioning brake system designed to control the brakes of the towed vehicle to help slow and/or stop the combinations of coach and towed vehicle.  A motorhome’s braking system is rated for operation at GVWR – not GCWR. Therefore, some chassis manufacturers recommend that a separate functional brake system be used when towing a vehicle that exceeds a given weight, as low as 2000 kilograms.

Tow Bar: An apparatus that connects a car or other towed vehicle to the motorhome and enables that vehicle to be transported with all four wheels on the ground. The tow bar assembly usually consists of two elements: the tow bar (or wishbone portion) and the base plate, which is the part that attaches to the chassis of the car. Te base plate is custom made for a particular vehicle and provides a safe point of attachment for the tow bar.

Tow Dolly: A short, two-wheel trailer coupled to the motorhome for transporting a car or other towed vehicle with two of the vehicle’s wheels off the ground. The towed vehicle is driven up the dolly ramps so that the two wheels rest on the dolly and the other two wheels are on the ground. Tow dollies are not applicable for certain rear-wheel -drive vehicles.

Towed Vehicle: A car, pickup truck, or sport utility vehicle pulled behind the motor home using a tow bar, tow dolly or trailer. This auxiliary vehicle often is more suitable to drive on backcountry roads or into town than a large motorhome. In addition, the motorhomer does not have to “break Camp” to make short trips into town. Also referred to as a dinghy or toad.

Trailer: A device that makes it possible to tow a vehicle with all four wheels totally off the ground. This eliminates concerns about transmissions, odometer mileage accumulation and backing into campsites, but loading and unloading can be cumbersome and time-consuming. The motorhome owner also must find a place to store the trailer upon arrival at a destination.

Tubular Steel Roll Bar: In coach construction, a steel cab component that can enhance the structural integrity of a cab assembly at the roof level.

Unloaded Vehicle Weight (UVW): The weight of the vehicle as built at the factory with full fuel, engine oil, and coolants. Does not include cargo, fresh water, LP-Gas, occupants, or dealer-installed accessories.

Vacuum-Laminated: In coach construction, one of several methods of applying pressure to t5he adhesive system within a lamination, such as a motorhome’s walls. Other methods include rotary presses (nip rollers) and flat presses.

Walkaround: A short walking tour around the exterior of the motorhome to make sure it is safe and ready for travel.

Welded Tubular Steel: In coach construction, steel that has been rolled into a shape (round, square or rectangular) with a projection welded seam. It is used as a sub-frame between the chassis and coach bodyworks. Usually produced by steel mills and shipped in straight lengths approximately 6 to 7 metres.

Wet Weight: The weight of an empty motorhome with fuel, fresh water, and LP-Gas tanks full but with waste water holding tanks empty. For an indication of how much weight can be added to the vehicle, including cargo and passengers, subtract the wet weight figure from the GVWR.

Wheelbase: The distance between the centres of the front and rear wheels on a motorhome. If a motorhome has a tag axle, the wheelbase is measured from the front axle to the centre point between the drive and tag axles.

Wide-Body: A motorhome that is wider than 8 feet (2.4 metres).