Hi,
here is my take on wind velocity.
Having a Penguin camper, we are much more aware of wind and more likely to suffer damage as a result of wind.
It would be difficult to define a specification of wind condition, let alone try to design to withstand this specified wind.
Whilst it would be reasonably easy to define a specification for a wind of constant velocity, unfortunately wind doesn't work that way.
The most damaging winds are gusts, especially gusts that come from different directions. These will be the most damaging ones.
Think about your poptop being hit with series of 30km/h gusts, alternating in direction. The first one pushing the roof to its limit in one direction, then suddenly, whipping around to gust in the opposite direction at 30km/h. That would be massively more likely to cause damage then a continuous wind at 60kmh.
Bracing the roof with ropes will help a lot since it will reduce the damage caused by such wind gusts.
In effect, when people talk of wind speed, it is mostly only an average. A 20km/h wind will very seldom be 20km for a sustained period. Any domestic measuring device will not be capable of providing much help in determining the velocity of wind gusts. Certainly not very intense wind gusts of very short duration. And these are the gusts that will most likely cause the most damage.
Over several years of camping, we have encountered severe wind on only two occasions.
Once at Lake Meredith near Colac which is notorious for strong winds coming across the lake.
The wind was strong enough that it was blowing tents away. We ended up putting the roof down, when a neighbour with a caravan came across and invited us to come inside and wait it out. I later discovered that there were nulls around the shore where the wind was noticeably less than in other places. We just happened to have set up where the wind was actually worse. We shifted about 300m away into a much calmer spot.
Second time was at Port Albert. The wind was really gusting. First pushing the top across in one direction and then whamm, shifting around and hitting full force in the other direction. By 2am, after no chance of sleeping, and becoming worried about possible damage, we pulled up stumps and came home.
As well as tying the roof down. We have done two other things to reduce the impact from wind. One is to point the van into the wind with the car attached. This presents the least surface of the van for the wind to act on and the car provides a wind break.
The other is to unhitch the car and position it to act as a wind break.
take care
Mike
