Timber Framers Guild Forums General General Forum Questions Rope for block and tackle

Hi all,

I have a quick question.

I'm getting together all the stuff I need to raise my shop, and one issue I've run into is finding the right rope. There doesn't seem to be a consistent way to rate them. For instance, I've seen polypropylene rope that states something ridiculous like 3000 pounds, but when you actually get it it has a working load of only 350 to 400 lbs. I need to use it in conjunction with my block and tackle and winch to raise the bents.

Any suggestions?

What are the blocks rated at? Are they singles, doubles or triples (number of pullies/block)? I have been using 1" manila, which is rated around 8,000 pounds, I think, so don't quote me on that. You might want to check out Timber Framing #67 March 2003, Grigg Mullen's article Raising Calculations and Prep. I want to switch to a lighter, modern rope but havent as of yet. Tim

Can't say I have extensive experience here in raising things--but raising people I've worked with a fair bit.

One book to check out is "On Rope" published by the National Speleological Society. I was able to find one in just about any library until I bought my own. It talks a lot about getting yourself up and down ropes. That's informative and useful, but the part you want to consider more is rescue work where loads of moving a person and medic approach those of a fair size frame raising.

By the way, I wouldn't personally use polypropylene for anything. I had a personal rule against it, and used it in a pinch to tie up my skiff on a very calm day. In perhaps six hours a gentle swell action untied a bowline with a safety. I didn't loose my boat, but I could have.
Never trust a knot in polypro: only a good long splice that's been properly seized.

With a few exceptions, I mostly use a sheath and core rope on the water, in the woods, and in construction.

I'm sure some talented folks with have a lot more to say.

Zach

check out the Amsteel ropes...http://www.amsteelblue.com/

http://www.sailingservices.com/running_rig/rope_spectron12.htm

I like the 1" manilla also. Doesn't stretch much at all, and easy to grip with your hands. Plenty strong for most applications, but do your math, of course. We don't do much with block and tackle, but sometimes it's handy of you have to lift something after the roof's on, like big staircase stringers. CB.

Anyone have a good source on the 1" manila? tb