We welcome your letters and feedback for publication. Safer boating on the road

Address to: The Editor, Boating New Zealand, PO Box 6341, Wellesley Street, Auckland 1141, or email editor@boatingnz.co.nz

FOLLOWING THE ARTICLE on trailers in the June issue and follow-up correspondence in July, I felt some items in the article were not fully addressed and l was left wondering why many trailers sold are marginal in their function and compliance, braking-wise. Furthermore I felt Greg Dutton’s reply did not take seriously the issue raised by your subsequent correspondent.

The reality is that the vast majority of passenger vehicles we use for towing are not designed for this purpose. They are designed principally for carrying passengers and their luggage. Some countries are more towing-oriented than others, for instance Germany, UK, USA and Australia, and hence there is greater consideration for towing in the design of their cars.

The article was somewhat dismissive of the ‘no brakes’ limit specified by car manufacturers. The 750kg un-braked limit which is often set by legislation (EU, Australia) is the maximum and recognises the load the vehicle may be carrying. Many smaller cars of less than 2.0 litres are typically less than this value, as are some mid-sized cars, eg Mazda 6, yet it is often advertised that a boat on an un-braked trailer weighing in excess of 1000kg can be towed safely by these vehicles.

Manufacturers’ quoted maximum braked capacities are often qualified by requiring heavy-duty hitches, load levelling equipment and sometimes by setting limits on passenger numbers, luggage weight and speed in the vehicle. Failure to adhere to manufacturers’ capacity ratings of course gives an insurer a reason to deny a claim should an accident occur.

More importantly from a practical perspective, I find it remarkable that there are so many rigs, braked and un-braked, being sold today with stopping performances that appear marginal at best. As a benchmark, a Holden Commodore weighing 1800kg has 4 x 300mm disc brakes. Trailer axle sets, as per Trailcom website are typically rated at 1500kg capacity for 225mm discs – max diameter for 325mm/13-inch wheels; and 2000kg for 275mm discs – max diameter for 350mm/14-inch wheels. So if you have a tandem trailer with a capacity of 2000kg on 13-inch wheels, you need 225mm discs on both axles. Yet there are boats on trailers with an on-road weight of 2500-3000kg with only one braked axle.

This is compounded by a disturbing trend to try to sneak under limits, saving a very few dollars, by saying: “Our rig weighs only 2350kg so we can get away with override brakes,” rather than fitting far superior, driver-controlled units. And this from some of the top builders and/or boat retailers.

You have to wonder if controlled testing is ever undertaken with a rig where both the trailer and tow vehicle are near to their maximum load capacities. It seems the manufacturers are failing in their obligations to provide trailers that are safe from a braking capacity perspective.

Finally there is the issue of compliance with the stopping performance standard, stopping from 30kph inside seven metres. It would be informative to hear feedback from manufacturers whether any car-trailer combinations have been subjected to this test, and whether they achieved the requirement.

I actually have to question whether this test is realistically achievable, given that the stop must be achieved in 1.7 seconds. Given that typical braking reaction time is considered to be around 1.5 seconds and there is a further 0.2-0.3 second lag to achieving full braking, it appears the standard may not be achievable, irrespective of braking performance.

It would be useful to see a set of tests run, looking at braking times and distances at various speeds – 30, 60, 90kph – for a number of representative rigs. Perhaps a 1200kg un-braked rig towed by a mid-size car such as a Mazda 6/Mondeo/vw Passat; a 2000kg tandem rig with brakes on one axle and then on both axles, towed by a full-size car like a Commodore or Falcon; a 2400kg tandem rig, override brakes on one axle only, towed by a near-limit vehicle such as a Ford Territory AWD; a 3000kg tandem rig, driver-actuated brakes on one axle only, towed by a ute with a near-limit capacity; and finally a 3500kg tandem rig, with driver-actuated brakes on both axles, towed by a luxury 4WD. Would any of the boat and trailer manufacturers be willing to rise to the challenge?

As a parting note, Alko, manufacturers of the New Zealand-developed Sensa Brake controller, has a good Youtube clip showing emergency braking stops.

I hope this letter will stimulate some thought to ensure our boating on the road is safer.