Thread: Timber on roof rack

I wrap the rope around the timber once and use a truckies hitch to pull it tight. If the boards try to slip forward or back, the rope tightens around them.

Silent is spot-on! Err no he's not, his'll work, but mine's better!

Don't fall for the trap of using too much rope. More loops = more places where the rope can work loose and this compounds.

If the timber bundle is symmetrical, ie a couple of planks the same size or a bundle of sticks say 5 high and three wide or whatever, you have a chance of stabilising it, if it's not, you'll need to secure the pack first.

Don't try to tie the timber together and secure it to the vehicle with one rope.

For tying timber together, brown plastic packaging tape is your friend.

Once the bundle is secure and the timber won't move within it, I usually use a quite loose loop with a bowline in it over the bar at one side, then a truckies hitch tightened to about the point where the doors on the opposite side of the car spring open.

If it's tight enough, the loop will have dragged itself hard against the bundle. If you want to hold it in a particular spot, use a clove hitch and a couple of half hitches instead of the bowline.

Don't use that nasty shiny hard poly or nylon cord, or even "soft" plaited or woven nylon, it has quite a lot of spring in it and you will never get it tight enough. Water ski ropes were designed for towing skiers not tying stuff down.

If you have braided sailing cord that's good, but silver rope is fine, and use something at least 10mm diameter.

If none of the above makes sense, do what Silent does, or get it delivered!

cheers,

P (Old sailors love their knots)

Go to Bunnies and buy a couple of the webbing style ratcheting hold-downs - only a few dollars. As Silent described, you pass the strap over the top of your pile of wood, right around under it, back over the top and accross to the other side of your rack. Tighten it up, and the loop stops it moving about.

Don't try to move big sheets about on the roof. I lost a large corner off a sheet of Harditex - I was only driving about 30km/hr.

Old sailors love their knots

Let's see; the rabbit comes out of the hole, goes around the tree, then back down the hole.... or does he go around the tree, into the hole, then back out of the hole.... or was that... oh bugger it. Buy some ratchet straps.

Originally Posted by TassieKiwi

Go to Bunnies and buy a couple of the webbing style ratcheting hold-downs -

Where's the fun in that??? Where's the satisfaction??? Where's the art???

Cheers,

P (who forgot to say, don't carry full sheets on the roof)

A full sheet might make a good wing so you can fly home

Studley

I used to carry steel tubes and used a packing variety of glad wrap to secure the ends then tie down.
Comes in spools like packing tape but about 4-6" wide.

We use the following method at sea to tie down the dinghy on the foredeck, and a yacht in a 60 knot storm jumps around more than a car, even on Sydney's roads.

Avoid the cheap plastic type rope if possible. Tie the timber down as tightly as you can using bowlines (easiest knot of all to break, even with the cheapo ropes). When tied, run the tail of the rope across and between the two loops (one above each roof rack) say four times. Pull like buggery on the remaining tail which will draw the top of each loop toward each other with a 8-1 advantage, thereby holding your timber in a vise like grip. Maybe use padding as the taunt rope will certainly mark the timber. When you cant pull anymore, tie off securely with a couple of half hitches, Jim lad.....

Bodge

Be careful you don't peel the racks off your roof with all that tension. You also might want to check that the sump still clears the ground.

Originally Posted by silentC

Be careful you don't peel the racks off your roof with all that tension. .

Yep, hadn't thought of that. It almost certainly will.

Borrow a mate's ute.

Bodge

when I was a young lad I was a travelling comms rigger (hcct, pttoeey!) we used to tie stuff down with whatever was handy. inso tape, occy strap, brown packaging tape, 12 mm, 16mm, 32mm hemp rope, ratchets, shirts, jeans, whatever. nothing ever fell off and we used to carry some major stuff around ( big dishes, boxes, iron work etc). dont let anyone tell you "Thier method is best - what a crock" the real answer is "Whatever is safe" inertia is your emeny - remember F=MA nasty rule to learn on a highway at 110kph...

theres no right answer - just like percy - you need friction. I suggest a clove hitch to start, then a truckers hitch over the timber to the other side of the bar. once this is tied off use the slack left in the rope to pull against the bight of the truckies hitch and clamp against the timber back to the start point - you can tie that off with a bowline or another clove hitch - essentially this provides extra tension on the tensioned portion of the truckers hitch - nothing is moving, believe me - hard to describe easy to achieve. of course if your roof bars are crap then your routed anyway for whilst fricition is your friend, inertia is your enemy.

nowadays on the mighty ute I use about 6 or 7m of 8mm bunjy cord or ratchets - havnt lost anything yet, nor do I think i will as I dont carry around 500kg of tower anymore .

breaking strain for rope fomulas :

natural fibre :
dia x dia (in mm) = SWL in kg

silver rope :
dia x dia (in mm) x 1.16 = SWL in kg

nylon rope :
dia x dia (in mm) x 2.26 = SWL in kg

steel rope or steel cable :
dia x dia x 8 = SWL in kg

NOTE then that most rope in austalian has a garanteed breaking strain of 10 (GBS). GBS is when the rope will fail eg a 10mm rope of nylon fibre is calc'd thus :

10 x 10 = 100kg safe working load
x 2.26 = 226kg swl
x 10 = 2260kg at which point expect the rope to fail (break)

Note rope is sold at GBS of 10 as 10 is the GBS required to lift humans (or chimps)

Note also that each TIED OFF LENGTH is the calc'd item... in the example above if I have 10 lengths of rope I can lift SAFELY 2260kg and the 10 will break at 22600kg!!! thats 22 tonnes mate - fark!


I say this as lifting is the same as tieing off or securing in both the eyes of the law and physics - dont not tie down enough - timber is heavy.

eg 1 x cube of steel is 7 tonne (approx)
1 x cube of aluminium is 4.something tonne (approx)
1 cube or wood is not much less.

anyway - here endeth the lesson - I hope it helps - PM me if you need a bigger lesson and I'll dog out my pract rigger text books.

cheeers big ears

ook ook!

Mr Bitingmidge, your method sounds good. I got everything except:

Once the bundle is secure and the timber won't move within it, I usually use a quite loose loop with a bowline in it over the bar at one side, then a truckies hitch tightened to about the point where the doors on the opposite side of the car spring open.

Don't suppose you have an illustration or photo, how many bits of rope do you use






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Carrying sheet material on roof racks is NOT recommended, but if you absolutely must, run the straps fore & aft, rather than across, and travel very, very slowly. Remember that you now have an aerofoil shap on your roof, and if you travel at any more than a crawl, the material will try to lift, and thin ply will easily tear on either side of the strap. DAMHIK.

Just remember if you lose the load and if it comes off the police will charge you for carrying an unsafe load.

The other interesting thing is now in NSW at least if you do lose the load the supplier is responsible for the way a load is tied on and if you lose it the police will also charge the supplier.

In a lot of instances the supplier wont let you leave their yard if the load isn't secured properly. I think you will find now all steel suppliers will not let you leave their yard with an unsecure load.