Trailer beware!
Tony Davies advises on what to look out for when buying a second-hand trailer
When the boating budget is tight there are superficially compelling financial reasons for considering the purchase of a second-hand rather than new trailer. Unfortunately, however, it is all too easy to buy a trailer that is either not suited to the boat, under-specified in carrying capacity or just poorly built. It must always be remembered that a trailer is a road vehicle, and it will be carrying probably your most treasured possession. If it fails, it will not only seriously damage the boat, but may also cause a major road accident.
On the surface, a trailer appears to be a pretty simple piece of kit; nothing more than a chassis on one or more axles with a set of brakes plus some supports for the boat. However, the design of a good trailer as opposed to a bad one is more complex than it first appears. Attention is given to the torsional stability of the chassis frame itself, the position of the axle/s and winch post in relation to the weight distribution of the boat and the method of supporting the boat evenly along the length of the hull.
Nose weight
The first point to bear in mind when looking at potential trailers is how the boat will sit on it and the weight distribution once the boat is in its proper position. These are the factors that will affect the nose weight bearing down onto the tow ball of the towing vehicle.
Acceptable nose weight varies from vehicle to vehicle and should be checked with the manufacturer. If the nose weight is too high, the front wheels of the towing vehicle will have less road contact, affecting steering and vehicle stability. With too little nose weight, the vehicle’s rear wheels will lose traction. Either scenario can cause snaking between the trailer and tow vehicle, which if not This is a new custom-built trailer, tailor-made to suit the boat and adjusted to fit perfectly by the manufacturer’s staff on first loading the boat. While it is quite possible to modify a standard trailer for fin-keel use, care must be taken to ensure that the hull supports are strong enough and securely attached to the trailer chassis. For a specialist trailer like this, it is probably safer to leave it to the experts! properly and quickly overcome can lead to total loss of control.
Modern trailers for trailer-sailers with lifting keels are generally equipped with ‘rollercoaster’ supports that consist of rows of relatively soft small-diameter wheels that not only make loading easy, but also spread the load over a wide area of the hull. It is also possible to have additional supports along the length of the keel when extra support is required.
The special requirements of other hull shapes (such as round-bilge) can be generally accommodated using keel rollers and chine supports rather than ‘rollercoasters’. It is certainly easier to find a second-hand trailer to fit a hard-chine hull than, for example, a fin-keeled yacht that needs a particularly carefully- designed trailer to ensure its safety when on the road.
Gross weight
Another point to bear in mind, and one which is particularly important, concerns the gross weight of the boat. If the boat is to be towed in cruising trim with all the equipment normally kept on board, then its all-up weight will be significantly higher than the manufacturer’s quoted displacement for the bare boat.
The gross weight of the boat should ideally be checked before a trailer is purchased, although in many cases this is impractical. Once the boat is on the trailer it can be easily be weighed by taking it to a council weighbridge. The weight of the trailer, as shown on the maker’s plate, can then be deducted. If there is no manufacturer’s plate, the trailer is either very old or an amateur-built job – which will mean taking the trailer back to the weighbridge empty and weighing it on its own. Of course, at this stage it may be found that the trailer is under-specified for the weight of the boat in cruising trim. For this reason, when looking at secondhand trailers – or new ones, come to that – it is always best to err on the side of caution when considering the gross weight of the boat and therefore the capacity of trailer required.
Once all the theory has been worked out, it is then just a matter of looking round until a suitable trailer is offered and then examining it for the many obvious and not-so-obvious faults that are to be found with second-hand trailers.