If you happen to have rope that's too thick for the torsion springs or the bowstring as-is, you can always unwind it. Regardless of the method you use, you should make sure that
- The plies don't get tangled with each other
- Each ply is wound to it's own coil
- The coils are large enough
If possible, buy correct diameter rope whenever possible; regardless of the method you use to unwind the rope, it's still a big hassle especially when working with long ropes.
Unwinding the whole rope in one length Edit
If the rope you have is fairly short and/or light, you may be able to unwind it in one go. Just anchor it's one end, take the other end and twist the rope until it's not twisted anymore, i.e. the plies are parallel. Then take a coil and wind one of the plies to it. Repeat the process for each ply and you're done.
Unwinding the rope in short lengths Edit
First anchor the beginning of still unwound rope:
Take a suitable (3-5m) length of the rope, tighten it and anchor it. The large coil containing the rope you're unwinding should be at this end:
Now start winding one of the loose plies to a coil. The rope will slacken as you unwind the ply, so you need to keep the rope tight (e.g. with your leg) as you move forward. A tight rope is essential if you wish to minimize arm movement and maximize unwinding speed:
Once you've unwound one ply, place it near the anchor:
If you want, you can number the coils and always unwind them in the same order. Once you've finished unwinding one length of the rope, unwind more from the large coil and carefully move all the smaller coils back to their original anchor point. Do not let the plies get tangled at this point, or you'll spend lots of time untangling them. Repeat the process until the whole rope has been unwound. Eventually you'll end up with something like this:
At top left a large coil and it's plies. This particular rope yielded 6 three-ply cors and 2 single-ply cords.