What diameter and weight were the old static climbing ropes?

Just curious. I was wondering how they stack up to modern day static cord, like the 7mm stuff used for tag lines.

1/4" was normal (it was the twin rope of it's day).

As I recall Blue Waters in the 80s-90s were typically 7/16 inch. They were heavy for their size.

How old is old?

Most static lines used for Rope Access work are 11mm - 7/16”. KMIII is probably the most popular rope I see. 

JP Hernandez wrote:

How old is old?

Most static lines used for Rope Access work are 11mm - 7/16”. KMIII is probably the most popular rope I see. 

Sorry, I mean Norman Clyde, “ the leader must not fall” old. Pre-modern ropes.

Okay that’s  old old, Pre-Kernmantle rope!

That an interesting question.  I actually have more questions now: Did they use hemp ropes back then? How large were they, 1”? Were those old ropes considered low-stretch static ropes or did the stretch quite a bit?

Haven't climbed on them, but a little googling says says finds a super taco thread about old ropes, that the old Gold-line was made in 7/16 (11.1mm) and 3/8 (9.5mm). (Maybe others as well)

http://www.supertopo.com/climbing/thread.php?topic_id=598147&tn=180

Even I can remember Goldline, but the OP was asking about Norman Clyde, and Norman probably never touched a nylon rope before the age of 60.  His noted climbs were done with ropes of manila or hemp, or "manila hemp", which minimal research suggests was an attempt to attach the good reputation of hemp sailing ropes to the new-fangled manila ropes (or maybe attach the fashionable current grooviness of hemp to old fuddy-duddy manila ropes??).  Based on a few data points, and liberal use of the cross-sectional area to extrapolate strength and weight:  

Either of those fibers is heavier, less stretchy and weaker than nylon.  I have one table that says the a hawser laid nylon rope will stretch ~40% before breaking.  A similar hemp rope would stretch only about 10% before breaking.  But that less stretch may have been better for sail control??

In those fibers, the equivalent diameter of the high tech 6mm Edelrid / Petzl 6mm rap lines would  weigh about 30% more and hold about 500lbs max.  The equivalent strength would require nearly a half inch and weigh about 150 g/m, or ~6x as much as the high tech stuff.

Compared to Bluewater 7mm static cord, the 7mm hemp rope would hold about 750lbs instead of 2300lbs , and weigh about 50% more.

To get the strength up over 3000lbs, which might be the minimum for leading today (under emergency circumstances, but with a rational hope of success),  a hemp rope would have been over a half inch, and weigh  160+ g/m.  

Modern climbers seem to prefer no more than 8-9 lbs for a rope weight.  That's roughly what a 50m  11mm rope, a 60m 10mm rope, and a 70m in the lower 9mm range weigh.  If the tolerance was the same back then, it suggests that most ropes would have been 80' or shorter.  But then again, with little or no protection on the lead, who wouldn't want to stop and belay frequently??

The 1947 provisional British Standard for climbing ropes is the only one that covers both natural and synthetic ropes. By the 50's only nylon was included.

Ropes were categorised by weight per 100ft and strength by breaking force per pound weight (500lbs/lb) and the three sizes for natural fibres were 5 1/2 lbs, 3 3/4lbs and 2 1/2 lbs. They were typically between 7.5mm and 12mm in diameter.

The corresponding nylon ropes were between 7mm and 10mm diameter and 2000lbs/3200lbs strength.

By the time I started climbing nylon ropes had settled to 1/4", 3/8" and 11mm, 1/4" hemp waist lines were still in use but hemp ropes except for top-roping were extinct.

Stretch for natural fibre was to be 16% and nylon 40% though in the later standard for nylon this was changed to 50%.