There is a grey area between unroped scrambling and roped climbing where the safeguard of a short scrambling rope is advisable. Used in conjunction with a sound understanding of 'alpine' rope techniques, such as running belays and moving together, and combined with a basic selection of protection (slings and nuts) a scrambler can greatly increase their safety.
Ropes are available in varying diameters and should be chosen according to the degree of added safety required. In other words, ask yourself 'What's the chance of someone falling?' In the past, ropes as thin as 8mm were used, but these are only recommended for moderate alpine snow protection. With a rope this thin it is almost impossible to hold it in a fall, abseil from it or withstand a fall over a sharp edge.
The current standard diameter for scrambling is 9mm
The current standard diameter for scrambling is 9mm, which although technically is usually a half rope (two must be paired together on proper rock climbs) they are suitable for single use on moderate terrain. If your scrambles are pushing into the low rock climbing grades, or you wish to have maximum security, then you may want to use a designated single rope. These can range from a lightweight 9.4mm, to a chunky 11mm. 10mm or 10.5mm is perhaps the most popular, as these are light, yet robust and offer good edge-cut resistance.
The length of the rope you carry can also vary, depending on the type of routes you climb. An old favourite is 30 metres (100 feet). It allows 15 metre abseils and provides enough length to reach good running belays, but not so much as to put the leader and second out of communication distance. Some scramblers take a shorter rope for particular routes they know well, or a longer length for scrambles that feature abseils - such as the Skye Ridge (40 metres).
Buy a full strength climbing rope, either cut from a reel or purchased pre-cut and packaged as such. If you do a lot of scrambling in winter it may be worth purchasing a rope that is dry treated, as this will improve the rope's ability to remain flexible in the cold. If this is the case, find another scrambler and buy a full-length 60-metre rope between you and cut it into two 30-metre lengths.
Never use static, semi static, accessory cord or any non-climbing specific dynamic rope. Using your old towrope will prove far more dangerous than climbing unroped!
Slings and other equipment
Again this depends on the experience of the party and the type of terrain. Your main safeguards are Alpine style scrambling, weaving among spikes and taking running belays around rocks, and most of all, not falling off. Carry a small selection of shoulder length slings (60cm), an odd assortment of wired or slung nuts (e.g. Rock/wallnut 3,5,7,9 and a hex 7 or equivalent) plus a few snapgate karabiners should suffice on most scrambles, allowing you to safely secure running belays.
This selection of equipment is can also be used as abseil anchors, just in case you need to retreat. This may be expanded by each climber carrying a length of abseil tat (5 metres of 10mm flat tape or 5mm perlon cord) but remember to carry a knife with which to cut it!