Hmm, you could get heavy linen thread for leather working or hand bookbinding. Then wax it with bees wax and roll/twist several strands together to make a thin rope. It would give you a thin strong rope which could be taken apart later to the original threads and used like the inner strands of 550 cord. It would require an awful lot of extra work and expense though. Also, while you may have trouble finding hemp rope, hemp thread is pretty easy to find for various uses at craft stores.

Hemp, considered such a strategic resource that at one time some laws in the US mandated that all land owners grow it, or linen were both tarred, more like saturated with pine oil, to create traditional Marline. This was used on ships for hundreds of years and was used for lashings, tying off and just about any other use. single-strand break strength was likely several hundred pounds and the tar made gripping it easy and kept it from rotting.

That's a good point, I hadn't thought about nautical ropes/lines. People have needed solid reliable ropes for boats and ships for thousands of years. Of course there's already a solution to the question. I know from reading about tying knots that sailors used to take apart damaged lines to do some pretty incredible practical and decorative work. I'd guess you can't get it now though. How thick was Marline?

Both tarred marline (tarred hemp) and natural hemp cordage and rope are available in the US (and most likely in the Maritime Providences of Canada), most of which is imported from Hungry. For tarred marline, visit a marine supplier in an area where sailing is popular, many will stock various thickness rolls of tarred marline cordage mostly around 2-5mm in diameter. For natural hemp cordage and rope, most craft stores will have hemp cordage for macramé bracelet and choker jewelry making. Thicker hemp cordage, rope and even hemp fabric can be obtained from sutlers (retailer sellers) of 18th and early 19th century items for historical reenacting/living history. They are around, although it can be a little challenging to find them.

Pete

I think the other posts have mentioned most of the natural fibers used for rope. When you are talking about ropes of 1/4 inch diameter or less, you are probably going to marline is the easiest to find. In larger size, manilla would probably become easier to find. If you cannot find it through a marine supplier, try to contact a ship's chandler. If that failed, try calling a maritime academy and ask someone there who teaches marlinspike seamanship about where they obtain natural fiber lines (maybe try http://www.imq.qc.ca/eng//)

All that said, I cannot see using natural fiber for anythign that I really need to count on. Any line that you buy should be inspected and renewed from time to time, but natural fibers of there very nature wear out much faster than synthetics, both when in use and not in use. They rot. A natural fiber rope can become useless without ever having been used or mistreated. So, in addition to not being as strong or useful, natural fibers wear out faster.

I have seen traditional marline sold by chandleries catering to the more hard-core, uncompromising, traditional sort of sailors. Otherwise often referred to a 'pigheaded fools'. The romantic sort who still dream of 'wooden ships and iron men', rolling seas and eschew many of the benefits of modern chemistry.

Nothing quite has the same aesthetic sense and wholesomeness of a traditional wooden boat with bronze fittings subtly scented by the smell of marine tar, teak and salt spray.

But your right. Many of the traditional materials do have serious problems. Most of the stuff sold as 'tarred marline' is actually tarred brown Dacron. This is mainly what you get if you buy marline from most chandleries like Defender:

http://www.defender.com/product.jsp?path=-1|118|311417|311408&id=21227


It isn't as aesthetically pleasing but it comes in a color and form that look a lot like the traditional stuff but it doesn't degrade much in sunlight or rot.

The old-time stuff is still sold:
http://www.tarsmell.com/marline.html

Ttraditionally it was sold in balls by the diameter and pound weight. It comes in various thicknesses. The thinner stuff can be used for stitching, finishing the ends of ropes and light lashings while the thicker is better for heavy-duty lashings like you might need to keep that 200 pound anchor secured when the boat capsizes.

They also sell "Stockholm tar" in case you wish to tar your own line. Or just like the smell.

http://www.tarsmell.com/tar.html

This stuff has a lot of uses. A dab on a tool handle will give you a good grip. Rubbed into wood and it will resist water, rot and insects. Applied to cloth and you have the basics of traditional oil cloth that is somewhere between water repellent and waterproof depending on how tight the cloth is and how much tar, and the specific mix, you use. Everyone has their own 'dope'. usually a mix of pine oil, wax, and enough solvent to make application easy. Wrap your tools in oil cloth and they resist rust.