Climbers need only a handful of knots to get by, but having a selection at your disposal makes you more effective and efficient. The pros and cons of the most useful ones are assessed here including: Figure of eight, bowline, clove hitch, Italian hitch, Prusik knots ... and many more.

The easiest way to learn a new knot is to get someone to show it to you, and then practise it ad nauseam until you can do it in your sleep. Deciding which knots to use when climbing is slightly harder, as often there are only subtle differences between them. Here we will concentrate on the pros and cons of each knot and where they are best used or avoided.

Figure of Eight on a Bight  

A bight is a fold of rope. If you tie a figure of eight in a fold of rope you get the knot plus a loop that is convenient as an attachment point. So anytime you want to clip something onto the end of a rope, this is the one to use.

Rewoven Figure of Eight

The tie in knot of choice for the majority of climbers. Its pros outweigh the cons considerably, as you can see from this list.
 
Pros:

• Easy to learn 
• Easy to see if it is correct
• If incorrect end up with overhand knot or figure of nine both perfectly safe knots
• Cannot come undone
• Still safe even if the stopper comes undone as long as you leave a long tail

Con: Quite bulky Bowline  

Still popular as a tie in knot with many traditional climbers and is perfectly safe but has a few more cons.

Pros:

• Quick to tie 
• Low bulk

Cons:

• More complicated to learn
• Can work loose during the course of a long day
• Must have a stopper next to it
• Less easy to recognise if it is correct

Clove Hitch  

Excellent for tying yourself to anchors.

Pros:

• Quick to tie 
• Easy to adjust
• Can be tied with one hand (if practised beforehand!)

Con:  Is quite wide, so beware of overloading a karabiner and putting stress on the gate.

Italian Hitch

A friction knot that can be used in place of a belay or abseil device, works best with a large HMS or pear shaped karabiner.

Pros:

• Quick and easy to tie 
• Plenty of friction to hold a fall
• Easy to operate

Con: Kinks the rope

Overhand  

The simplest knot you can tie. It can be used in place of a figure of eight. Popular for tying two abseil ropes together.

Pros:

• Quick and simple 
• Small and neat, less likely to jam when pulling abseil ropes

Con: Small radius knot so can be hard to undo once loaded

Double Fisherman (see bowline)

Half a fisherman is used as a stopper knot when tying in using a figure of eight or bowline. A double fisherman is used to tie two ropes together as in an abseil. It is best to separate the two halves by first tying a reef knot. This makes it easier to undo after it has been loaded.

Pro: Easy to undo once loaded

Cons:

• Complicated and slow to tie
• Bulky and prone to jamming in cracks

Prusik Knots

A prusik loop is constructed by tying 120cm of 5mm rope in a loop with a double fisherman's knot. The closed loop should be approx 50 cm long. Prusik knots have various uses including ascending ropes, protecting abseils, and in rescue scenarios. There are many variations; these are the most commonly used ones.

French Prusik

Four to five wraps around the rope and clip the two ends. This will then bite the rope when loaded. It can also be released when under load which makes it useful as a clutch or autoblock. 

Pros:

• Quick and simple to tie   
• Works in most situations
• Can be used to self protect abseil
• Releases under load, so useful in hoists, etc

Cons:

• Releases under load 
• May release unexpectedly, always have some other form of back up

Ordinary Prusik  

Two to three wraps inside itself around the rope. 

Pros:  

• A good biting knot 
• Ideal as the top prusik when climbing a rope and as the pulling prusik in a hauling system
• Does not release under load

Con: May jam

Klemheist  

Variation on the French prusik. Instead of clipping the two ends, pass the long end through the short end. Works well using tape if you have no prusiks.
Larksfoot

Wrap a sling around something (harness, karabiner), push one end through the other and pull this end.

Pros:  A good way of using a sling at almost its full length. Particularly useful for making an attachment for the harness to clip to anchors or abseil stations when not tied into the rope.

Con: There used to be concerns over its strength but it is now agreed it causes only a minor decrease in strength.

Tying off the belay plate

A way of securing the belay plate so you can take your hands off when swapping leads at a stance for example, or as the first step in most rescue scenarios.

Pro: Effective and secure; Con: Tricky to learn