Roof racks, wind speed and broken boats

I was interested to read that the British team pulled out of the race in France because the wind snapped a roof rack mounted ski...

As I do quite a lot of long distance driving with skis, I would be curious to know:

a) how many other people have broken/damaged skis this way?

b) what were the conditions? (car speed/wind speed & direction etc)

c) what is the fastest you can safely travel with a ski on the roof in calm conditions without it breaking (I hit 120-130kph during overtaking, but normally travel at ~100kph)

d) is there a significant difference in lateral (?) strength between fibreglass, kevlar & carbon fibre? Could anyone quantify the difference?

e) which is better, ski in a cradle facing upwards, or ski upside down on the crossbars?

f) do any of the ski manufacturers test for this/test to destruction/ have recommended speed limits/guidelines?

All feedback would be welcome. From a personal perspective I'd really like to know whether I can sit on 120kph in calm conditions, and at what crosswind speed to pull over.

cheers

PS: I've been driving long distances with boats for ~30years (rowing, sculling and recently skis), and never lost or damaged anything. However I recently almost lost a ski while crossing a high level bridge @ 80kph in a (est) gusty 40knot crosswind. The crosswind was so strong it pushed the kayak cradle across the roof rack, and the ski ended up diagonal across the roof. I now put tape around the roof rack bars to prevent any lateral movement in the cradle.

Can't answer any of your questions but have had same experience with crosswinds turning ski 45 degrees on roof racks. Subsequently bought a car that could have racks a long way apart (about 1.5 m, Thule rack) and it is very sturdy, hasn't moved yet, but I don't travel fast with any craft on the roof, no greater than about 100 km/h and have stopped when the crosswinds are strong. It isn't worth damaging the ski, car or more importantly injuring someone else for the sake of a few minutes.

When I first got my ski, I did what everybody did and put it on the rack upside down.
First time at highway speeds in the wind and it moved around everywhere. Stopped, put lines front and rear and that was better but the tiedowns had to be so tight that I was worried about hurting the ski.

I went and bought cradles the next day.
Now the tiedowns are only tight enough to keep the ski in the racks.
It moves up and down a bit as the racks flex, but I think overall it is under less stress.
I've never felt worried enough to use front and rear tiedowns again.
My bars are only 70cm apart.

There is no perceivable distortion of the hull when strapped in.

I'd be interested in knowing how the broken boats were loaded.

Being in Australia, we never go over 110km/h, usually 100

For high speed driving, the most important thing to do is to place the ski as far back on the rack mounts as possible (for example, 20 ft ski, 4 ft rack spread = about 4 ft of ski ahead of the front saddle and 12 ft of ski to the rear of the rear saddle). This places the least amount of lateral stress / torque on the ski in crosswinds. Of course, it then becomes very important to use a large red flag hanging from the 12 ft of ski hanging off the rear of the car. Erik

Maybe?
If you look at the layup of most skis, there is considerable re-enforcement near the bucket.
So strapping on as you suggest may put most of the stress in the weakest part of the boat.........

I have noticed that with the Thule Aluminium Aero bars that the cradles still move laterally in strong crosswinds, no matter how much I tighten the T-fasteners. I suppose that is where the steel bars are better since the cradles are tightened from the side.

I usually align the skis so that the straps in front crosses the area between the pedals and the front of the cockpit. The area in front of the cockpit on the ski's deck is just to weak, even more so if you have a ski with a soft core material like some of the carbon skis.

Rightarmbad wrote:

Maybe?
If you look at the layup of most skis, there is considerable re-enforcement near the bucket.
So strapping on as you suggest may put most of the stress in the weakest part of the boat.........

One of the guys I paddle with bought the racks that are able to extend the distance between the cradles from the original aero bars, so the cradles are about 2 metres apart...the result, cracks in the gelcoat where the tiedown straps contacted the deck.

Like him I would have assumed the greater distance apart the cradles were the less stress was placed on the boat by sidewinds but now that this has happened it is clear that the cockpit area does indeed have the best structural strength for tying down.

To add to this debate I have seen many cars come flying past me on the way back from events doing 120 plus and I cringe at the thought of the stress placed on the boats. I cruise at about 95-100km/h and if the winds are strong I may even drop down to 90km/h.

While there may not be a failure of the boat on the racks it may be setting the boat up for future problems.

The ideal set-ups I have seen have the boat on the roofrack cradles and have a pole from the front bumper and towbar up to the bow and stern offering additional flex protection, they are not usually ties to these extra supports, they just cradle them to stop side to side movement.

One day I'll get one fabricated for my X-trail.

I was just driving across the Sydney Harbour Bridge yesterday with a howling westerly blowing when I saw the front of my ski move about 1/2 metre sideways - scared the crap out of me!

My ski is a brand new Think Evo II with cg-tech finish - only been in the water about 4 or 5 times - so I was particularly worried.

Needless to say, I slowed down considerably and hoped I'd make it off the other side with a ski in 1 piece - which I did.

The Thule cradle had come loose with the sideways force and the tie-down was somehow a bit loose (not sure how that happened).

On the return journey in the afternoon I put 2 tie-downs from the nose of the ski to hooks (towing points) under each headlight, plus a single line from the back of the ski to the tow bar. They helped, but there was still considerable movement - partly because the ski was in a cover and the ski slides around inside.

My roof racks are way too clase together, but they are fixed points provided by Subary (Liberty/Legacy). I'll consider this on my next car purchase.

Thule make a 'goal-post T-bar hitch' that provides a support at the back of the car - I'm seriously considering getting one. I'd love one at the front too! If using this system, you would only need a loose tie-down at the ends to prevent side-ways movement and there should be no stress (damage) to the ski from this.

Next time I drive on windy days:
- take ski out of cover (cradle will grip hull better)
- 2 tie-downs at front
- 1 tie-down at back
- hope it doesn't break
or
- leave the ski at home.

I'm gonna go out on a limb here and say that all problems with racking come back to basic common sense.

Make sure the rack has been set up to fit your hull and have some sort of mark to always put it in the right place.
Mine lines up with the C in the stickers.

Check fittings regularly.
Slow down when it is windy.
All covers make any tie down system less effective.
Bow and stern straps when required.

Double check strap tightness and whether they are running the most direct route and not be able to shift to a looser configuration, before moving off, and any time you stop.
Be aware that some straps can loosen when they get wet.


I've never understood the cult of the boat cover.
Why?
Like your boat might get wet?
It might spend the day in the sun?
Maybe an insect might randomly get splattered on the pointy nose.

What are they to protect against that the boat is incapable of handling?
It's not like a few extra hours traveling in the UV is going to kill it.

Re Covers ...

For me, I use the cover because when I store my ski in the roof of my car port the bow and stern get some morning and afternoon sun, so the cover will protect the boat when it's not in the water ... and I live near the bush so there are a lot of spiders (cover keeps them out of the boat).

Also, when I paddle early in the morning, I then drive straight to work and I don't want to draw attention to the ski in the car park.

Other than that - your comments re commen sense approach is absolutely the right approach.