Coroners Findings - caravanning triple fatality

This is the link (again)

Coronial Findings

DIO

Thanks for posting the link DIO. The report doesn't give you much confidence in the way that Police crash investigation works does it !

One witness stated that the missing gas bottle was "immaterial" to the weight on the tow ball ! Well that guy needs a few math lessons in how to do weight & balance calculations. There are a few people on this forum that have aviation experience where weight & balance is a life & death calculation every day. A full gas bottle with a lever arm of more then two metres from the balance point between the axles may have been just the amount required to be the difference between stable and unstable when towing. There was no evidence of the lever arm for the water tank and no knowledge of what items were stowed in the caravan. Damage to the jockey wheel was acknowledged by the coroner and the representitive of the manufacturer but not by the 'expert' witness!

It is always the leeward side of a truck that is the most unstable on a windy day. I is up to the caravaner to make the allowances

I attended this accident shortly after it occurred.

On the day there was a strong north wind. The explorer and the B-double were both travelling in a westerly direction towards Morgan.

The collision occurred when the explorer driver lost control as the B-double passed. The explorer ended up under the front of the B-double off the northern side of the road.

The caravan continued on until colliding with a tree.

This tragic event was devastating for the family of the deceased persons and for the driver of the B-double.

I remember that accident, I saw that Ford Explorer at the Police compound in Ottoway, the whole roof flattened. And the people in the Explorer were going to meet the owners of that very truck that killed them. they were good friends, according to the police at Ottoway compound.

Regarding the Towbar:
1: why didn't the car have a heavier duty towbar fitted in the first place, no use having a say 1200kg towbar on the back of a big 4wd.
2: Maybe the Caravan seller should be fined for allowing the caravan to leave his yard because it was unsafe.
eg; the local sand/metal garden centre won't load more than 500 kgs of loam into your 750 kg unbraked trailer.

I think the truck sucked the car/caravan towards him like a vacuum

The issue of surface area -horizontal forces is very interesting.
I have not put any real thought into that.
It is obvious the van in the photo does not carry a great towball weight.
Think how we load our vans. The kitchen food pots and pans would have been over the axles. A large amount of storage under the beds to the rear - easy to get.
The photo's don't show where the spare was kept. Was it in the boot or on the back of the steel bumper taking weight from the towball.
The weight of the bottle and jockey wheel are going to be proportionally less than their actual weight...30kg at at a point 1 third/2 third proportion towball to axle distance reduces to 20kg at the towball.
Northerly wind the driver would most likely have a steering bias into the wind or to the right.
It does appear the surface area at the front would be less than the rear of the van.
As the truck approaches the rear of the van the air pressure would increase on the rear giving a clockwise result.
As the front of the truck pulls alongside the the centre of the van the air wake would be pushing the front of the van to the left - the low pressure zone past the front of the truck would be drawing the rear of the van back towards it.-a change to counter clockwise force which would generate a clockwise result into the towing vehicle and a tendancy to steer into the truck.
The van obviously travelled fairly well when disconnected ,jockey wheel or not which would also support a low ball weight finding I would think.

Definitely worth keeping in mind.

A sad time for the Jong family irrespective of what the actual causes were.