Right or wrong, this is what I do. I choke my lifeline above the sling, which is placed close to the top of the stem. Choked, it won't come off. However, even so, it could, so I prefer to place my steel core lanyard below the sling, but above the block, as there's a space for it there to not be trapped, as the block is thicker. I understand that this isn't optimum, as the sling can be pulled down from the forces involved, and could still trap the lanyard.
Alternatively, an adjustable friction saver can be used, through which the lifeline is run, which eliminates the rope trappage issue, or any problems were the stem to crack open, as sometimes happens.
The reason for placing the block and sling within about 6-8 inches of the top is to reduce the free fall moment....which can also be further reduced with rapid slack removal...which requires a ratcheting lowering device.
Pretensioning the load also takes all the slack out of the system, and will actually open up the kerf of the cut being made... contributing to the reduction of the free fall moment. With these methods, since the log's center of gravity will fall less before braking is applied, it is possible to stop it's downward movement quite quickly when needed, say, when the working room has diminished low down on the stem.
Again, while Reg's system doesn't allow for all of these techniques, it is surely bombproof with its redundancy....and that is a good thing.
nice work Reg!
