To say it clear: rope ladders are out! Since single rope technique is used, they are only a romantic staffage. Nevertheless we want to say a few words about rope ladders, just for the sake of completeness.
Rope ladders are ladders which are made from two long, parallel ropes which are connected with short steps. Those steps are made from various materials, wood, iron tubes, aluminium, or even rope. The main benefit of rope ladders, is the possibility to roll them and to carry them in this compact, barrel like form. This is necessary to carry them through narrow and winding caves.
In caves typically stainless, lightweight and robust materials were used, so the typical rope ladder was made from two very thin tightropes and alumninium tubes for the steps. The result is not too heavy and more or less stainless.