Technology: From axle load to keel rollers - how to trailer correctly
By boat from Hamburg to Berlin in six days? Or would you prefer six hours? Of course, the journey is the destination and leads on its own keel via the Elbe, Elbe-Havel Canal and the Lower Havel Waterway through a wealth of nature and cities such as Lauenburg, Magdeburg and Potsdam. Meanwhile, the trailer captain is stuck in a traffic jam at the Wittstock/Dosse motorway junction. Or not.
In any case, he arrives at his destination much faster than his "colleague inland skipper". What's more, if he wants to, he can be relaxing in the sun on his boat off the coast of Croatia or in Niendorf on the Baltic Sea just a few days later. Provided he has adhered to the most important "rules of the game" when travelling by road. Our trailer ABC reveals what you need to bear in mind when travelling with a trailer and how to get to your destination safely and comfortably.
Axle load
The maximum permissible axle loads for towing vehicles and trailers can be found in the respective vehicle documents. Be careful: Even if the permissible total weight of the vehicle is not reached, the permissible axle loads must not be exceeded. Important: If the trailer is coupled, please note that the drawbar load of the trailer is added to the payload of the towing vehicle and therefore to the axle load of the rear axle.
Adapter
All new multi-track motor vehicles registered after 1 January 1991 with a maximum speed of more than 60 km/h and their trailers must be equipped with one or two rear fog lights. This means that if you want to supply the trailer with continuous current or switch on reversing lights as before, the 7-pin plug connection to the trailer, which was obligatory until then, is no longer sufficient. This is why 13-pin systems are now state of the art. To be able to connect a trailer with a 7-pin system to a car with a 13-pin system or vice versa, there are adapters available from accessory dealers and well-stocked DIY stores.
Towing capacity of towing vehicle
Legislation has limited the trailer load for passenger cars to the maximum permissible gross weight and for off-road vehicles to 1.5 times the permissible gross weight, up to a maximum of 3.5 tonnes. The towing capacity of a vehicle is ultimately determined exclusively by its manufacturer - within the framework of the legal requirements, of course.
The permissible trailer loads - braked and unbraked - of your car are noted in the registration certificate, Part I, in fields O.1 and O.2, and must not be exceeded. Important: The drawbar load of the trailer is added to the payload of the towing vehicle.
The following example shows how this affects the trailer load: The towing vehicle has a maximum trailer load of 1500 kg. The trailer has an effective weight of 1575 kg and a drawbar load of 75 kg. The drawbar load of 75 kg is added to the payload of the towing vehicle so that the towing vehicle can tow the trailer weighing 1575 kg without exceeding the permissible trailer load of 1500 kg.
One exception is the 3.5 t upper limit for off-road vehicles. In this case, the trailer must not be heavier than 3500 kg. As a rule, the specified trailer load always refers to a gradient of 12%. For some towing vehicles, higher values are possible on lower gradients such as 8 % and 10 %. If these values exist, they must be noted in the vehicle documents.
Trailer coupling
Trailer couplings in ball head design are approved up to 3.5 tonnes. Above 3.5 tonnes, a jaw coupling must be used. Ball head couplings are available in fixed and detachable versions. Important: When inserting the detachable coupling, make sure that it is correctly locked so that the trailer does not become independent when driving.
Work gloves
A pair of gloves should be kept handy in the vehicle. They protect against dirt and minor injuries when refuelling - especially with diesel -, checking the oil, in the event of a flat tyre and also when coupling and uncoupling the trailer.
Overrun brake
Boat trailers up to a maximum total weight of 3.5 tonnes are generally equipped with overrun brakes in Europe. Overrun brakes are usually drum brakes, disc brakes are still the exception. Power is transmitted from the overrun device to the brake via a cable pull or hydraulically.
Important: Overrun brakes must have an automatic reverse function that allows the vehicle to reverse without having to engage a reverse lock manually beforehand.
Loaded
The main weight of the boat must be on the keel rollers. To do this, these must be adjusted according to the course of the keel. If possible (note the drawbar load), the boat transom should be flush with the last keel roller. Side supports should support much more than they carry and be adjustable to make slipping easier. If you want to reduce vibrations, front side supports are also recommended from a certain boat size.
In any case, the boat must be firmly attached to the trailer (see lashing). If the load protrudes more than 1 metre beyond the rear reflectors and lights, it must be marked by suitable means - bright red flag, sign, cylinder or a light with bright red light (at dusk and in the dark). Important: Do not leave any loose objects in the boat while travelling, as these can fly around uncontrollably, damage the boat and - in the worst case - endanger other road users.
Lighting
Like the towing vehicle, the trailer must be equipped with functioning rear lights, brake lights, indicators, rear fog light and two rear reflectors. From a trailer width of 2.10 m, skippers must fit a white clearance light on each side facing forwards and a red clearance light facing backwards. Trailers that are longer than 6 metres must be fitted with lateral yellow, non-triangular reflectors on the long sides.
Trailers over 6 metres in length put on the market for the first time from 1994 onwards must also have amber side marker lights. As these lights - unlike the light strip - cannot be removed for slipping, water can penetrate the lights, they can deteriorate and can cause a short circuit in the electrical system. For this reason, some trailer manufacturers have special authorisations and do not have to fit these lights.
Boat cover
A cockpit cover saves more fuel than a complete cover. Although the full tarpaulin protects the boat better, it must be lashed down perfectly if it is not to cause chafe marks on the boat.
Braking with the trailer
The braking distance is always longer with a combination than with a solo vehicle. For this reason, you should always keep your distance (at least half the speedometer) and drive with foresight to avoid abrupt braking manoeuvres. Special care should also be taken with unbraked trailers. With an unbraked 700 kg trailer, the braking distance increases by around 7 metres compared to a braked trailer of the same size. And that's a lot of wood, especially in an emergency, where every centimetre counts.
Front wheel
The front or support wheel of the trailer should be checked carefully before every journey. The spindle for turning up and down and the clamping screws (two are always better than one) must be firmly tightened. A tip: A rope can be used to secure the spindle on the winch stand to prevent it from shaking loose.
Bow support
The bow support is used to secure the boat to the front of the trailer. Important: Use the cable winch to pull the boat into the bow support until both side supports of the support are firmly in contact with the bow.
Checklist
The following points should be checked before travelling with the trailer:
- Is there still enough time before the next MOT for the towing vehicle and trailer?
- After loading, set the drawbar load to the maximum value.
- Check the tyre pressure on the car and trailer when the tyres are cold and check the tyres for damage.
- Take the trailer to the scales, weigh the axle loads and the total weights of the car and trailer, take weighing cards with you. They are helpful during police checks.
- Take your driving licence, vehicle documents for the towing vehicle and trailer and - for journeys abroad - green insurance cards.
- Check the lights on the car and trailer, check that the trailer coupling is locked and that the breakaway cable is correctly positioned.
- Do not forget to cover the propeller.
- Check the lashing of the boat and tarpaulin.
Anti-theft device
Every trailer driver should secure their trailer adequately against "thieves". Otherwise they run the risk of losing their insurance cover in the event of theft. The best protection is a safety device that can be used when the trailer is attached and detached as well as when driving. Axle manufacturers such as AL-KO and accessory dealers offer such locks.
Driving licence
Which driving licence do I need if I want to drive a car and trailer combination? The answer to this question would go beyond the scope of this issue. Therefore, we will deal with this topic in the next issue of BOOTE.
Dangerous goods
In principle, the transport of diesel and petrol by road is a transport of dangerous goods. However, exemptions must be observed. For example, for the transport of dangerous goods carried by private individuals - provided that these goods are packaged for retail sale and are intended for personal or domestic use or for leisure and sport, provided that measures are taken to prevent the contents from being released under normal transport conditions.
If these goods are flammable liquid substances that are transported in refillable containers filled by or for private individuals, the total quantity must not exceed 60 litres per container and 240 litres per transport unit. Tanks are therefore not considered to be "packaged for retail sale".
Nevertheless, the following applies in practice: if a tank is permanently installed in the boat, it can be full during transport. If you have to reckon with every kilo - and who doesn't have to - you will do without a full tank and reserve canister when trailering anyway.
speed
In Germany, the maximum speed for car-trailer combinations is set at 80 km/h. If the towing vehicle and trailer meet the technical requirements described in the 9th Exemption Ordinance to the German Road Traffic Regulations and these have been tested and documented by a monitoring organisation such as TÜV, DEKRA or GTÜ (entry in the vehicle documents, sticker), it is permitted to drive at 100 km/h on motorways and motorways. Abroad, however, the regulations of the respective country always apply
Green insurance card
With a few exceptions (Eastern Europe), a green insurance card is no longer compulsory when travelling abroad. However, insurance companies still recommend the "green card". If you have it with you, it makes it much easier to deal with an accident abroad. Since trailers have been required to have their own licence plate (1992), they also need their own insurance card. Of course, this is only available if you have taken out your own insurance for the trailer (see Insurance).
Height of the load
The maximum permissible height for loads in Germany and other European countries is limited to 4 metres. It is possible to obtain a special permit, but the conditions are so extensive that it is better to leave such transport to the professionals.
Licence plate
Sports trailers - including boat trailers - are not subject to tax or insurance, but have had to have their own licence plate since 1992. The licence plate can be obtained from the registration office.
Keel rollers
Keel rollers are load-bearing elements and should therefore be adapted exactly to the keel of the boat. The rollers and their shafts must be checked for damage and ease of movement at least once a year.
A tip: The yellow keel rollers made of polyurethane are much more robust, turn much more easily than their black rubber counterparts and are therefore the first choice for anyone who slips a lot.
