Paracords as Bow/Stern Tie Down

I’ve straped two canoes onto my truck rack using cam buckle straps and I wanted to know if its OK to use paracord (550 lb strength) for my bow and stern tie downs or should I try something heavier?

No way, keemosabie
Dat stuff ain’t strong enough under dynamic loading. Ah’ reecoomend at least 5/16 or better yet - 3/8 or 7/16".



FE

Knot so good
Para-cord doesn’t hold a knot well unless you pull it so tight that it is difficult to undo when you want to untie it. Use a larger diameter rope and you will have a lot easier time of it.

A good rule o’ thumb
For most rope a safe working load is 1/10 of its maximum tensile strength. For life safety applications it’s usually 15 to 1.



Even good knots have a breaking strength of only 70% of the unknotted rope strength, and 50% is more realistic for common knots.



Dynamic loading on a bumpy road can be impressive.

5mm
Yeah, I’d use at least 5mm cord. It’s easier to tie and untie, a lot stronger and comes in cool colors.



Other posters are correct in saying that your boat generates a lot of force bouncing around up there. Why risk your boat or your rig for 5 bucks worth of climbing rope.



-James

http://www.adventurecanoe.com

Besides being too small for
good knotting qualities, 550 paracord also is obnoxious to use due to nylon’s affinity for moisture. Tie it on dry, get rained on, and it gets loose. Tighten it up wet and when it dries it will be drum-tight.



I vote for 5mm polyester boating line.



Jim

You better use 1" steel cable or…
you’ll be in trouble with the gang here!



Cheers,

JackL

Discounting the strength ratings
Good Para-cord has a lot of stretch. For bow/stern tie downs a good poly rope, 1/4" or better will suffice. The dynamic loading is less a factor when you have “belly” straps. The real advantage IMHO is simply minimizing lateral movement and as a safety measure.



YMMV

Wes

550 Lbs
Guys, the paracord I have has a load strength of 550 lbs! The diameter is about 5mm. I’ve already tried it on my rack and it ties great. Are you really telling me to get something stronger than 550 lbs for a bow and stern tie down when the canoes are already securely belly fastened to the rack with cam buckle straps. I was just at Home Depot and to get a rope stronger then 550 lbs I would need to get something over an inch in diameter.

Not making sense

– Last Updated: Jul-14-09 9:17 PM EST –

Okay, so what if it breaks at 550 pounds. Read some of the other stuff posted. Stretch is a big thing, since bow and stern lines, properly aligned, can help a lot to minimize boat sway, but since they are NOT very tight, it takes a line with minimal stretch to make that happen.

You say it's easy to tie? Ha. Wait till you try a good braided 3/8-inch rope instead. You'll never go back.

You say you'd need something more than an inch in diameter to exceed a breaking strength of 550 pounds? You MUST be confusing the "working load limit" with the "breaking strength". They are not the same. Does it make any sense that the only rope that will exceed the breaking strength of what you have is one that's more than 25 times as thick? Heck no, but that's what you just said. Think about it.

Anyway, decent-quality rope is almost dirt-cheap. Yeah, you can spend a small fortune on climbing ropes or other special-purpose stuff, but can get good braided "poly" rope isn't expensive at all, and it is "tough" compared to parachute cord. How many times can you cinch down a trucker's hitch with parachute cord before the line saws through itself? Not too many, but you can do that with 3/8-inch braided poly, or anything similar, for years with no trouble.

para confusion
Your 5mm cord is not “paracord”. Actual paracord is around 2 or 3mm and does not have 550lb tensile strength. Your 5mm cord is called 5mm cord and it will be fine.

If you’re into the whole bow/stern tie down thing.


and um… home depot?

"paracord"
Cutting some slack for the original poster, I will point out that the stuff often called parachute cord is thicker than that. I just measured the stuff I got at REI, which MOST folks call parachute cord, at 4 mm in diameter. Whether it’s really the stuff they use for parachutes or not isn’t relevant to this discussion. Even 4- or 5-mm stuff lacks the qualities you need for “good” tie-down material. It’s great for tents and tarps, though. There’s just much better stuff for keeping your boat on the roof, for about the same price or less.

I like 1/2" braided w/core …

– Last Updated: Jul-14-09 11:30 PM EST –

...... nylon or polyester . Easy on the hands !!

I hate little skinny ropes ... tough on the hands when torquing tight . A nylon rope will stretch a little and rebound fast (great shock absorber) , Polyester doesn't stretch as much .

I totally can't stand polypro or polyethelene ropes in any size !! Although they aren't toooo bad for a dock line ...
These ropes are UV degraded , hard and slick , distort when stretched and "do not" rebound (no memory), that's why they twist all around themselves after just a little bit of use , a mess ... so what if they float , big deal !! They are considerably weaker than nylon or polyester , chaff easily , rough on the hands , and are crap for making any kind of release knot .

Summary
Just to be sure I understand what everyone’s been suggesting, and I do appreicate everyone’s input, I would be better off getting a 1/4 inch to 1/2 inch nylon rope that doesn’t stretch, even though it has a load strength that is much lower than the paracord?


polypro
You must be talking about that slick twisted stuff.



Good braided polypro – like throwbag/water rescue rope – is easy on the hands and knots well.



It wouldn’t be my first choice for tiedowns, only because it’s weaker than other materials for the same diameter.

Now be ye talkin’ working load rating

– Last Updated: Jul-15-09 8:26 AM EST –

or breaking point (tensile) rating? Cuz, working load be anywaar fro' 15% ta 35% of de tensile ratin'.

FE

Breaking Strength
How does one determine this? Because I never see this on any of the labels.

Just a suggestion. It’s what I use.
http://www.westmarine.com/webapp/wcs/stores/servlet/producte/10001/-1/10001/19834/377%20710%201755/0/Running%20Rigging%20By%20The%20Foot/Primary%20Search/mode%20matchallpartial/0/0?N=377%20710%201755&Ne=0&Ntt=Running%20Rigging%20By%20The%20Foot&Ntx=mode%20matchallpartial&page=CategoryDisplayLevel1&isLTokenURL=true&storeNum=2&subdeptNum=490&classNum=11452



I like that it comes in colors to compliment my boats and cars, and that it’s call “yacht braid”.

come back tomorrow
The committee will evaluate the appropriateness of your color choice of rope.