Strapping cargo to roof of car drama.

November 26, 2005 5:31 AM

Help me tie/strap/secure an IKEA box of furniture that we need to return to the store on the roof of my friend's 4 door sedan.

The kind helper at the IKEA loading dock strapped it down for her and she got it home easily, only to her horror to find out there were major pieces missing. IKEA said her only recourse was to return it to exchange it.
I volunteered to help her, but now positioned as the Alpha male on this 45 minute trek from NYC to planet long island I realized my knot tying and physics fu will fail me as i've never completed any of the merit badges the boy scouts offered 20 years ago.
We will be on a busy expressway and the last thing I need is to stop all commerce and holiday travel by having this big box slide off @ 55 mph ensuring the humiliation of the overturned tractor trailer live animal stock spill that is always captured for posterity by 2-8 traffic choppers, further recording my trauma for the internets to share the video on Monday morning through work emails and links captioned with titles like "asshat ruins weekend for the northeast, here's the video..."

I'm thinking I definitely need to take into account braking and acceleration and prevent any give forward or backward on the roof..... any other tips?

Super extra points and "mad props" (as the kids are wont to say today) for any flash or videos showing how to tie knots. I can also work with step by step diagrams of knot tying or even demonstrations of how something secured on the roof should look like.

I have a shoelace and a pack of cigarettes that I will strap to a paperback book to practice before i head on over to her apartment.

posted by stavx to Grab Bag (24 answers total)

It's really just an issue of having adequate strength rope, using your weight to keep it taut, and tying multiple square knots. You can get fancier, but that's all you need. If you want to have to cut the thing loose because the knots are so tight, use natural fibre rope and soak it in water before you tie. You will have the Gordian Knot on your friend's car.

I can't believe you're thinking this hard about it. Relax!
posted by Mayor Curley at 5:43 AM on November 26, 2005

Do you know anybody with a truck/van/SUV/wagon you could borrow for a few hours? If not, and you are really concerned, you could rent a Uhaul, or something similar, for the afternoon. That would eliminate the need to tie it to the top of a sedan.
posted by bwilms at 5:52 AM on November 26, 2005

The Ikea near me rents vans at an hourly rate... (I think, technically, it's not Ikea themselves but Budget or one of the other car rental places... but they're located at Ikea.) I'm not saying that you won't be able to figure this out, but you might want to give them a call and save yourself the headache.
posted by ph00dz at 5:59 AM on November 26, 2005

one tip - when you've tied it down as well as possible, find two parallel, but fairly well separated stretches of rope, and tie something between them, pulling them together. this will tighten everything up, if you do it right.

also, if you double the loose end rope over before tying the knot, you end up with something that's easy to undo (like a bow, but not as sissy).

after you've driven a short way, stop, get out, and check/tighten as required.

(you have some kind of roofrack mounted on the sedan, right? if not, at least put a blanket or something on top to reduce scratching).
posted by andrew cooke at 6:29 AM on November 26, 2005

If you can't tie good knots, tie lots of them. Same with rope. Use lots. By the time it looks like one of the victims in Alien, you're home free.

But seriously, the trick is having lots of "X" diagonals or very tight ropes. If you can't do (B), do (A).

Another trick is to take slack out of ropes by tying another rope to the center of the slack and pulling it sideways.

Repeat until you can't get the doors open. People will stare, but the highways will be safe from you.

The three most useful knots are the square knot, the bowline and the taughtline (aka Midshipman's) hitch.

If you have one of those stupid modern plastic cars with nothing to tie things to, use 16 rolls of duct tape. If you had a 1957 Caddie, you could just put it in the trunk.
posted by warbaby at 6:31 AM on November 26, 2005

The Ikea near me rents vans at an hourly rate...

Bloomington, Minnesota Ikea next to Mall of America has a big sign offering vans--$19.98 for first two hours, as I recall.
posted by gimonca at 6:33 AM on November 26, 2005

And here's a cheat sheet (PDF) for handy field reference when you're out there in the big blue room with the great resolution (aka the World Wide World).
posted by warbaby at 6:50 AM on November 26, 2005

You realize, of course, that if you do make the news, this will require a FPP.
posted by warbaby at 6:51 AM on November 26, 2005

But, above all, Be Prepared!
posted by warbaby at 6:56 AM on November 26, 2005

The Zeppelin Knot! The world's greatest know for joining two lines.

People will be amazed. If you get really good at this, maybe your girl friend will let you tie her up...
posted by warbaby at 7:06 AM on November 26, 2005

er, knot.
posted by warbaby at 7:06 AM on November 26, 2005

Oh, and we want pictures.






Of the car and payload, silly.
posted by warbaby at 7:07 AM on November 26, 2005

What you want are some roof rack straps like these--nylon webbing with camlock buckles. I have these for my windsurfing boards, but they're also made for canoes, and I've seen generic variants at hardware stores. They're about 12 to 16 feet long, anywhere from $15 to $30 for a pair. When I've traveled with rental cars without racks, I've opened the doors and put the straps through the inside.
posted by tommassit at 8:56 AM on November 26, 2005

If you don't already know how to tie knots, forget the rope. Go to the nearest Costco, or BJ's, or (probably) Wal_Mart, and buy a set of tie-down straps. They are very strong, easy to use, and are cheap at those places.

I do know how to tie knots, and I have some excellent rope, but the tiedowns are what I use, because they are so easy.
posted by Kirth Gerson at 9:07 AM on November 26, 2005

Or what tommassit said (but the straps are much cheaper than that at the stores I mentioned)>
posted by Kirth Gerson at 9:09 AM on November 26, 2005

The Trucker's Hitch is the best knot for securing loads. With it, you can secure any load very tightly with just a couple of ropes.
posted by nicwolff at 9:58 AM on November 26, 2005

Nicwolff gives the best advise, the truckers hitch is the knot you want to use. However unlike the site he links to, I would start with an inline figure 8 for the midline loop. Do not just tie lots of knots, a) this weakens the rope, b) the weakest knot will be your undoing (or the ropes). Also make sure you are using good rope and not just something for like clothes lines. (I've seen this done way too often.)
posted by MrBobaFett at 10:45 AM on November 26, 2005

Good advice MrBobaFett, a half-knot can jam and it's better to tie an eight knot. Actually, you don't need to tie a knot to start, you can just take a bight in the standing part, twist it three times, pull a bight through the end, and lead the bitter end back through that. Here's a picture.
posted by nicwolff at 1:13 PM on November 26, 2005

The taughtline hitch is far stronger than the trucker's hitch, which seriously lowers the breaking strength of the line. and it doesn't require the two half-hitch stopper. And it is adjustable without untying.

Enough time has passed, yet no reply from the poster. Any reports of huge wrecks in the vicinity of the Long Island Ikea?
posted by warbaby at 8:09 AM on November 27, 2005

I agree with nicwolf that the driver's hitch is better than the trucker's hitch (properly called the "hay hitch" and only used by farmers.)

All thing's being the equal, a real salty sailorman uses the taughtline hitch.

I'd like to see a pictures of the paperback, the cigarette pack and the shoelace and a comparison shot of the car with payload.

I suspect that they would demonstrate that the difference between theory and practice is much greater in practice than it is in theory.
posted by warbaby at 8:18 AM on November 27, 2005

Huh? The trucker's or driver's hitch gives you a 2-1 ideal mechanical advantage on tightening the rope; the tautline hitch just secures the bitter end back to the standing part in an adjustable way. Use the tautline rather than two half-hitches to finish off the trucker's hitch if you want but the tautline's no replacement for the trucker's.
posted by nicwolff at 12:54 PM on November 27, 2005

Well, if you must use rope, secure one end with a bowline, then wrap your parcel and secure the other end to the standing (wrapped) line using a Prusik knot. That will let you tighten it easily and repeatedly.
posted by Kirth Gerson at 1:05 PM on November 27, 2005

Nic, seriously, the trucker's (or more properly, farmer's) hitch puts a bight in the standing part that is as tight as can be and then puts a double strain on it through the cleat or whatever. That means the standing part is guaranteed to break right there. It's a weak know because it puts all the strain on a single point and focusses the strain through the bight.

You've just reduced the breaking strength of the line enormously. The fact that you get mechanical advantage to break the line is not a good thing.

As a matter of fact, magicians use the trucker's hitch to break ropes that other's can't.

Knots Weaken Rope -- They do! A great deal is written about which knots weaken a rope most. If this concerns you, you are using rope that's too thin!! An angle, a kink, or a knot, stresses the fibers unevenly and weakens the rope. Although some knots in some ropes are claimed to only weaken a rope to about 80% of its rated strength, other knots weaken a rope to about 50%. It is therefore simpler, and certainly safer, to assume that even brand new rope will perform at no more than 50% of its rated breaking strength. And, if the rope is old, worn, or damaged by chemicals - expect considerably less.

The far superior taughtline hitch maintains the full strength of the line. And you can tighten it as much as you want by "swinging on the halyard." Plus it can be untied and doesn't need a stopper to keep it from untying.

Likewise, the zeppelin knot gives you the ability to bend two lines together without reducing the breaking strength appreciably. Both the sheet bend and the square knot roughly halve the breaking strength of the line.
posted by warbaby at 4:46 PM on November 29, 2005

Well, it's good to be careful, but as your quote there says, if you're worrying about the weakening effect of your knots on the rope, you're not using strong enough rope. For the purpose of tying a big box to the top of a car, a trucker's hitch in reasonably new 3/8" non-stretch rope will destroy the box and the car before it comes anywhere close to breaking. If you're really worried, tie a slip knot on the bight and bring the bitter end back through both the loop in the bight and the end of the bight - like this - which spreads the load and rounds out the turn in the rope.
posted by nicwolff at 11:36 PM on November 29, 2005