Trailers
It is important to have a good trailer. Trailer sailers of 8 meters in length 26.5 ft, can weigh 1.5 to 2 tonnes and a trailer another ¾ tonne. Total weight will determine the type of vehicle needed to tow them, but more importantly affect the design of the trailer. Multi-axle is common in boats over 6 metres. Smaller diameter wheels lower the trailer making launching easier but are less suited to long distance highway hauling. Trailer brakes are generally fitted to larger trailers and in some countries heavy trailers o must be fitted with breakaway automatic braking.i.e. either electric brakes or hydraulic/vacuum brakes with reservoir. These types of brakes have the advantage of remote (car) operation so that the trailer can be braked separately and before the vehicle brakes. Stopping the rig with trailer brakes on only can quickly settle down fishtailing, caused by overtaking vehicles. It is also safer to brake the trailer first on slippery road surfaces to avoid jack knifing. Electric controllers are easier and cheaper to fit to towing vehicles but electric actuators at present can only be fitted to drum brakes, whilst hydraulic systems are needed for disc brakes. Boat trailer brakes often get submerged in salt water, and corrode quickly. Disc brakes are easier to inspect as drum brakes can hide corrosion, but both types are problematic mainly because automotive components used on trailer brakes are not designed for this duty. Stainless steel has been tried for brake discs, but is not ideal for it does not disperse heat well. Some manufacturers produce aluminium bronze brake discs for boat trailers which are much superior, combined with stainless steel or aluminium bronze callipers and stainless hydraulic lines, they can be immersed regularly in seawater without corrosion. There are also now electric driven/hydraulic pump units which can be fitted to boat trailers, enabling electric control of hydraulic disc brakes.
The optimum trailer chassis material seems to be galvanised steel, which should be galvanised inside and out with adequate drain holes in all members. Aluminium has been tried but may suffer from fatigue failure . Axles and wheel rims should also be galvanised steel. Axle carriages should ideally be movable on the chassis frame to allow adjustment in tow ball vertical load for stability optimizing. The compromise is that usually for hauling at highway speeds the carriage needs to go further back, but for launching and keeping wheels out of the water the carriage needs to be further forward. Some manufacturers have developed carriages on metal rollers within the frame, so it is a matter of removal of a few pins to reverse the carriage forward before launch. Special waterproof rear lights and connectors that can be immersed are available. Wheel bearings need to be adequately rated for the load and best fitted with bearing buddies and kept regularly pumped with marine waterproof grease, not auto grease. The roller system depends on the hull shape and should support the yacht at no fewer intervals that the internal rib spacing or at bulkheads in glass boats and coincide with them. Tilt trailers can assist in keeping wheels from being submersed each time a boat launches or retrieves, but some consider that such mechanisms are not easy to make tight on the drawbar and promote side sway on the road. Rollers should be regularly inspected, without the boat. Polythene seems to be the most durable roller material with different harder grades available for aluminium. Regular maintenance is vital for boat trailers particularly at the beginning of the season and before a long haul.
Read more about this topic: Trailer Sailer