In the latest issue of Propeller magazine, technical editor Peter Morgan wonders if a large percentage of towing boats (and horse floats and commercial trailers) are operating within the rules set by Land Transport New Zealand (LTNZ).
While he believes most boat owners are not trying to break the law,
he suspects they may be doing so unwittingly.
However, as with all aspects of the law, ignorance is not an excuse if one is caught not complying.
And if there is an accident, an insurance company could refuse to pay for any damage caused by a non-complying trailer.
According to Morgan, a consulting forensic engineer and a marine designer, there are six key areas of concern. These are: load overhangs; lights; the size and number of safety chains and shackles; brake specifications and braking performance, and the gross combined weight limit of the boat and the trailer.
The load overhang issue is one that affects mostly trailer powerboats, especially those with outboards or stern drives.
The maximum allowable distance from the centre of the axle or centre of a group of axles to the rear of the load is 4m. This is not normally an issue but, in the case of an 8.5m (or bigger) powerboat, this could be exceeded if the engine(s) are tilted fully.
Even on boats that comply with the 4m rule, if the engine projects more than 1m beyond the rear of the trailer frame (as almost all outboards do when tilted fully) then it must carry a warning device attached to the overhanging end of the load.
During daylight hours, this is the brightly coloured flag that is almost always seen when a powerboat is being towed. Legally, it must be a clean white, fluorescent red, orange or yellow flag, at least 400mm long by 300mm wide. Alternatively, owners can fit a breakable or fragile hazard-warning panel (also at least 400mm long by 300mm wide) that shows an orange diagonal stripe (200mm wide) against a yellow or green background and facing the rear.
At night, a red lamp (facing the rear) - mounted near the rear or the transverse centre of the extended load - must be fitted. This light must be clearly visible in fine weather at a distance of at least 200m.
While almost all professional-built trailers have the correct lights installed at the time of manufacture, Morgan says that these must be visible at all times. If a tarpaulin, other cover or any part of the "load" obscures one of the lights, temporary lights must be fitted to compensate for this.
The size and number of safety chains and shackles required depends on the size of the rig being towed. A trailer with a laden weight that is less than 2000kg has to have a safety chain or cable.
This has to be short enough to prevent the trailer's coupling from hitting the ground if the trailer is disconnected. It also has to be strong enough to hold the trailer secure in all situations.
The chain cannot be secured to the trailer with a shackle and all components (chain, shackles and bolts) should have a braking strength of at least twice the trailer's gross laden weight.
Rigs that weigh between 2000-2500kg need either a breakaway brake or two safety chains that cross each other when connected. These must be able to withstand a load at their attachment points of at least twice the gross laden weight of the trailer.
While rigs with all-up weight between 2500-3500kg do not need safety chains, they must have a self-actuating breakaway brake.
The specifications of brakes also depend on the all-up weight of the rig being towed.
However, any brake couplings must have a manufacturer's rating appropriate for the gross laden weight of the trailer.
For rigs weighing less than 2000kg, brakes are not required as long as the car and trailer can be stopped as described above. Breakaway brakes and parking brakes are also not required.
On rigs weighing 2000-2500kg, brakes are required on each wheel of at least one axle. These may act indirectly (override) or directly (controlled by the driver). Neither a breakaway brake nor a parking brake is required.
On rigs that weigh 2500-3500kg, brakes are required on each wheel of at least one axle and must be controlled by the driver. A self-actuating breakaway brake is required, as is a parking brake. This must be capable of indefinitely holding the loaded trailer on a slope of one in five.
The parking brake must also act on at least half of the road wheels (on a triple axle trailer, the parking brake must be fitted to two of the axles).
When it comes to braking performance, the main rule is that all rigs (trailers and their tow vehicles and everything on board), regardless of size or whether they are braked, must be able to stop within 7m from a speed of 30km/h.
The other issue Morgan raises is that of gross combined weight, or GCW. This is the combined weight of the towing vehicle, passengers, trailer and load.
If the GCW is less than 4500kg, there are no problems and an ordinary Class 1 driver's licence is all that is required. However, once the GCW exceeds 4500kg, the driver legally needs to have a Class 2 heavy vehicle driver's licence.
Morgan says to consider the amount of gear, fuel, water, food and drink that are being carried, the number of people and the size and weight of both the boat and the tow vehicle.
Double check
* Load overhangs
* Lights
* Brake specs
* Brake performance
* Gross combined weight limit
Want to know more?
Check out Peter Morgan's feature in August/September issue of Propeller magazine or at propellermagazine.co.nz
Stay legal and safe on the road
Match the size of the boat to a suitable tow vehicle, attach bright flags to overhangs during the day and make sure your trailer has stop lights and indicators. Photo / Supplied
In the latest issue of Propeller magazine, technical editor Peter Morgan wonders if a large percentage of towing boats (and horse floats and commercial trailers) are operating within the rules set by Land Transport New Zealand (LTNZ).
While he believes most boat owners are not trying to break the law,
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