I've last towed in 2006. For the past fifteen years or so, I hardly drove anywhere, medical reasons. Age is a 🐖. 

We consider getting a small rough road capable caravan, then to stick to rural back roads BUT there will come times when we'll be forced to use N1, N2 and N7.  

Although I passed my EB type K53 with a 98% mark, I need to get as much advice as possible, as my confidence had waned.  

My typical speed is 90-100km/h, but I like to sig at 80 when I tow, just to provide for a safer stopping distance. (Some tow a caravan and a speed boat at 140+.....that won't be me!)

How does one stay safe when overtaken by an articulated truck, say 5-axle interlink, when towing a caravan?  

I once towed a 15' Sprite - unladen - behind an empty 3-litre Cortina bakkie. All went well until I went over the crest of Bakoondshoogte between Ashton and Swellendam. Very suddenly, at around 90km/h, the caravan started swaying wildly. It was hard getting it under control.  I don't know what had caused the swaying, other than knowing from general aviation that updrafts against a hillside can cause air turbulence.  

After having tried everything to no avail, I accelerated smoothly and gradually, which seemed to cure the sway.  The rest of the journey to Hartenbos was uneventful. 

Advice & comments welcome. Educate me. 

Hi Pieter.  There are but a few factors that has a implication on towing with stability.

1. Is the speed at which you tow.  Here you should not have a problem towing at 80-90km/h.
2. How the weight in the caravan is distributed. Too much weight behind the axle is a no no.
3. What the towing combination looks like. Are you towing a large caravan with a small light weight car?
4. Un foreseen circumstances like cross winds, bad roads and so on.

I would just advise that you make sure that the vehicle you tow with is legally capable to tow the caravan you have. On the registration plate of the vehicle there are two large weight figures.  The biggest one is the Gross Combined Weight (GCM) example 6650kg This is the weight of the tow vehicle and the caravan/trailer combined specification by the manufacturer.  The second largest is the Gross Vehicle Mass (GVM), the weight of the tow vehicle laden example 3450kg.  Subtract them from another and it will give you the towing capability of your vehicle specified by the manufacturer.

Take note how you pack the caravan.  All heavy equipment above the axle or in your tow vehicle.  There is a Youtube video available showing the implications on packing the trailer.

With unforeseen circumstances I always tow with a stabiliser. It is not there to rectify a known stability problem, it is there to assist in these conditions.

Pieter, when a van start swaying it feels like when the car slides on a slippery road and your instict developed with years of driving, makes you correct accordingly. This is absolutely incorrect. It exercarbates the problem. What you should to is to grip the steering wheel in the straight forward position. The swaying will stop almost immediately. You often hear people say you should brake hard or accelerate hard. Obviously such opposites tells you at least one is wrong. In fact both are wrong. I suspect this is advice 'I have heard' and is in the same catagory as the advice of putting a brick in the cistern to make a toilet use less water: somone thumsucked this and spread it as a fact.

We have been towing a caravan for 40 years and after my first bad experience similiar to what you describe I towed the caravan to a quiet road and did some experiments until I was sure I understood the problem and the solution.

Do give us some more info on your profile please and take what Leon said above to heart.

When the unladen van started swaying behind the equally unladen 3l Cortina bakkie, I did the right thing by trying to forcefully steer straight ahead, and easing off the throttle gradually.  The slight reduction of power immediately exacerbated the swaying, causing me to slightly accelerate, and this stabilised the rig. 

Having listened to others, I supposed the sway was caused by a strong updraft from the valley's bottom, and hit me as I came over the hillcrest....about a thousand feet above the valley floor.  

We often experience similar updraughts when flying around Brandvlei and Kwaggaskloof dams near the Windy City, Worcester.