BAD BAD Weather

We are just a couple miles inland of the southern-most tip of Lake Erie (Port Clinton, OH) and experienced our first Tornado Warning Sirens a couple days ago.  The warning was for an area about 20 miles away but that was close enough for us.  We looked over our shoulder at the Rig and headed to the RV Park's shelter.  We had only high winds and hail but you can never be too careful.

Well... Last night and today we are sitting in very high straight-line winds (25 mph+ with gusts upwards of 35 mph) and torrential rain; going on 36 hours now and predictions are for 16 hours more.  We are rocking when gusts hit but we are parked about 20 degrees off parallel to the wind so we're okay.  The rigs across the way are more perpendicular to the wind and most have even pulled in their slides.

So what does one do while hanging around in a wind buffeted RV on a Saturday?  Watch old movies, of course, and surf the InterNet. 

I found this posted on several RV forums re: RVs and high winds.

If you want to calculate an estimate of how much wind speed is required to overturn your trailer, you can use

V = SQRT(W*t/{0.00666*L*(h-d/2)*(h/2+d/4)})

where
V = wind speed, mph
W = trailer weight, lbs
t = trailer width (tire center-center), ft
L = trailer length, ft
h = trailer height (from ground), ft
d = tire height, ft

For example, with W=8000#, t=8', L=30',h=10',d=3' -- the calculated overturning wind speed is 81 mph.

As expected, the most sensitive factor is trailer height. If the height is increased to 12', the overturning wind speed reduces to 67 mph.

The above equation does not account for any yaw instability effects. It only considers the simple blow-over effect. Wind-related accidents can occur at much lower speeds due to yaw instabilities. In that case, the effect of greater height of a 5er would tend to be offset by its more stable connection to the toe vehicle.

The above equation, and a lot more interesting stuff, can be found in this Wyoming Highway Department Report.

The more simple to read version is

 

When the data for our fifth wheel is plugged into that formula, the result is a wind threshold of 69 mph perpendicular to the rig.  The physics says all is okay but with the slide covers flapping, the trees outside our window bending over, and the whole rig rocking a bit, it is a tough sell to the emotional side of the brain. 

(For those that don't like to do the math, I've posted a spreadsheet at www.ScottHoldren.com/TheRig/WindSpeedCalculator.xlsx  )

We have family currently sailing the world in a sail-catamaran and I imagine this is how they feel when they make a run to what they call a "hidie-hole"during hurricane season.