In reply to andy:
>So do you have to deliberately let the rope slip a bit?
NO
I know plenty of people that would rather have someone lighter belaying them on a lead fall so not to come to a sudden stop. this even more a issue with a child as they are so much lighter! Stepping in can help.
there many previous threads re this topic and an article by Adrian Berry
to quote
"First of all, just to clear-up a few myths, the following is not dynamic belaying:
1) Dynamic belaying involves giving lots of slack - FALSE!
The more slack there is in the system, the further the climber will fall before the rope can start to do its job and the more force will need to be absorbed. Unless there is an obvious hazard that you need to steer the falling climber away from, give only enough slack to allow freedom of movement.
2) Dynamic belaying is about letting the rope slide through the belay device a bit - FALSE!
Arresting a fall requires an almost instinctive response, there isn't enough time for the fine motor skill required to allow for controlled rope slippage, the risk is you will drop them altogether (note: this can be done but requires gloves, a figure of eight as a belay device, and preferably a back-up belayer.)"