Thimbles needed in Dyneema Lifelines

[Mountsbay]

In the context of people being thrown against lifelines I would have thought that the important issues would be to do with the geometry of the system and how much energy the system could absorb by deformation. Very high tensions can be generated by applying a relatively low load in the middle of a taut line if it is very low stretch and its ends are fastened to rigidly fixed points. If there is some slack in the line initially the tension created will be much lower - ie geometry matters. A given weight dropped from a given height might break a low stretch line (eg spectra) but not break a weaker but more elastic line (eg nylon) - ie energy absorption by deformation matters. Obviously the weight of the thrown person also matters as does the speed with which they hit the lines. If somehow the person were thrown up at the lifeline rather than down at it that would matter too. I am not sure what is means to say that someone is thrown into something at 2.2 g's but perhaps that matters as well.

[John D]

If you're going to directly connect your dyneema lifeline to your pulpit, don't ring hitch to the bail. Ring hitch to the nice fat stainless steel tube. Place the hitch inside the bail, so it can't slide up or down the tube. Using the bail as the connection point means bending the dyneema into a much smaller radius turn.

Even when lashing from a thimble in an eye-slice to a pulpit (or pushpit) go around the larger tube and just use the bail to keep the lashings from sliding.