by Collyn Rivers
Caravan Facts and Opinions
Caravan facts and opinions are not the same. People assuming opinions for facts one for the other cause ongoing and major misunderstanding. This article explains how and why.
There is a major difference between caravan facts and opinions. An opinion is valid in areas such as ‘what campsites to choose’, and ‘pubs to eat in’ etc. Engineering issues are substantially different. Most are based on work and engineering ‘laws’ long proven. Newton’s (1684) Laws of Motion now enable spacecraft to navigate vast distances. Much of what we know about electricity stems from the 1800s.
Engineering facts relate also to the strength of materials. Engineering opinion, however, may relate to acceptable safety factors, desired life expectancy etc. There, engineers and accountants often disagree. The days have gone when bridges had a safety factor of seven. Now, many caravan makers recommend far too low tow ball weight, despite there being a known and factual correlation with safety.
Too often, opinion is seen as valid as fact. One forum posting noted: ‘my 120-litre three-way fridge doesn’t cool properly’. Questioning showed it drew 15 amps through a hopelessly-thin cable. Respondents factually advised voltage drop was the cause. Resultant responses were that’s only an ‘opinion’. A mention of Ohms Law (that quantifies voltage drop) copped this salvo. ‘Ohm – never heard of him mate – but what would that Ohm fella know about it anyway. The real world’s different.’
Many people posting use terms like ‘real-world’, and ‘commonsense’ to defend total absurdities. Some resort to abuse. This is particularly so with caravan electrics. Some threads become so abusive they are locked.
A still encountered opinion is: ‘people need exercise to be healthy – its commonsense that batteries need exercising too.’ The facts are the opposite. Battery heaven for most is non-use but charged to balance internal loss. But that’s like keeping a lead-acid Labrador.
This issue also arises with caravan supply cables. Forum posts still advise joining supply cables together is safe ‘as long as connectors are kept dry.’ Such opinion seriously endangers. Supply cables are specified to ensure circuit breakers cut current flow within 0.4 seconds. This is essential to save human life. Extending length by joining cables restricts current flow. This can prevent circuit breakers from acting within that vital 0.4 seconds. Raising this point, however, results ‘I’ve been doing that for fifty years mate’. Or the #@%^$ electricity regulators don’t know what they are talking about.’ And any number of similar and seriously dangerous opinions.
Trailer and tow vehicle stability
My own speciality (of caravan and tow vehicle stability) exemplifies this. Some owners refuse to accept Newton’s Laws of Motion relating to jack-knifing. ‘I tow a 3500 kg (7715 lb) caravan safely by a 2500 kg (5500 lb) dual-cab ute’ is often posted. But many doing that find out the hard way that it is not safe. This a fact. It is backed by insurance company records supplied to RV Books.
That not understood is that any caravan towed via an overhung hitch is fundamentally unstable. It is safe to do so, however, within limits. The major limit is excess speed. Far from all rollovers, however, are due to driver error: some caravans have appallingly stability. A few are mobile accidents seeking a time and place to happen.
Furthermore, another (and hugely dangerous) opinion is: ‘the positioning of weight in a caravan does not matter as long the nose weight is right’. That, if applied to rear-end weight, is virtually a recipe for jack-knifing.
Yet another is that excess caravan weight is a far greater cause of instability than length. It is the opposite.
Caravan facts -Responding on forums
It is impossible for non-technical people to know who to believe in forum (technical) issues. Furthermore, vital threads become permanently locked at a moderator’s whim. This can leave absurd claims unchallenged. Many engineers have ceased posting. Or, as in my case (on a major Australian caravanners forum) being banned from posting. Why? That people reading my responses may then buy my books. This ban had the opposite effect. Within days my book sales soared.
By and large, people read forums for entertainment and seeking free information. This may not work – they lack the knowledge to know whom to trust.