Firstly; Less rope is used which potentially allows longer pitches to be climbed by the leader.
Secondly; It can create a single attachment point at the belay reducing clutter and tidying the stance.
Thirdly; Slings are relatively light-weight and extremely strong. Many rated at 22 kN.
There are several methods of using slings to equalise anchors at a belay. 4 methods are described below.
The sling is clipped through both carabiners, pulled down to create a V and the the figure of eight tied.
Advantages: Quick, simple and effective.
Disadvantages: Requires a 120cm or larger length of sling, particularly when anchors are not close together.
The sling is clove hitched to one carabiner, a loop of slack created and then clove hitched to the other anchor. Once both clove hitches have been tied the sling is equalised with a figure of eight.
Advantages: Quick, uses less sling and is easy to adjust.
Disadvantages: Must be proficient with each knot, harder to create with less than a 120cm length of sling
The sling is clipped through each anchor, pulled down to create a W and then equalised with a figure of eight.
Advantages: Allows more anchors to be incorporated in to the belay, quick and effective.
Disadvantages: Requires more equipment and a large length of sling.
Tie an overhand knot in the sling, attach a loop either side of the knot through each individual anchor and then have the overhand knot rest in the balance point. Ensure that the carabiner is clipped through both halves of the sling.
Advantages: Effective and tidy.
Disadvantages: Tricky to tie.
Points to remember when using slings to create a belay at a stance:
- Ensure that each anchor is independently tied off.
- Ensure that each anchor is equally loaded.
- Slings must remain under a static load and must never be shock loaded.
- You can shorten large slings but cannot lengthen short slings.
- As slings do not absorb as much energy as dynamic rope the anchors will be put under greater pressure. Choose your anchors carefully.
- Try to ensure that the angles between anchors are 60 degrees or less. This will ensure less force is placed on each anchor and the direction of load is correct.