In a previous article introducing technical rigging, it was established how traditional rigging still very much has its place, but has been improved with innovative equipment and techniques. The fundamentals of potential forces were also introduced, to help explain the reasoning behind developing such equipment and the legal requirements under the LOLER 98. (lifting operations and lifting equipment regulations) remind us of our obligation to use such equipment to improve safety where necessary.

The danger of technical rigging operations lies within using a system comprising of many components - if the components are not matched adequately to the system, many weak links can occur. Another danger is using advanced equipment and techniques without a thorough understanding of either. A technique with high potential for disaster is probably the Speedline -the topic for this article.

The concept of the Speedline stemned from the High Lead logging industry - that is techniques involving winching logs up and down slpoes using a wire suspended between two towers, one at the top and one at the bottom of a slope. This was accomplished in the last century via topped trees as poles with steam, oxon or horse power. The technique in tree removal involves tying a line high in the tree and tensioned and secured on the ground to gain clearance for branches over obstacles. Gravity is used as the driving force.

Although often complex to set up, they can save a lot of effort dragging branches and timber by transporting the crown piece by piece to a pre-determined target area. Sometimes they are the only choice to efficiently remove trees set back in a border and surrounded by an understorey of vegetation.

There are many forms of Speedline ranging from very simple to very complex. The danger inherent within all of these is the amount of tension put into the line and the subsequent loading of the line and anchors. This will generally be compounded further by the leverage applied to the tree through tensioning i.e the possibility of breaking or uprooting a tree. It is also possible to permanently damage a line by over tensioning it beyond the working load limit.

The commonest form of abuse I have seen and heard of practiced, involves tensioning a line as tight as possible via some form of winching tackle, and then shock loading large branches and tops directly into the line!?! I have even seen root plates lifted during demonstrations. This is a good way of committing spectacular suicide if the incredible forces are considered for a moment! As the line is tensioned upto 150 degrees, the loading on the anchors will be approximately double that of the load when it reaches the half way point. As the line is tensioned further upto 180 degrees, the loading at the anchors will approach 10 times that of the load ! So, if a falling Oak log hits the tensioned rigging with 500kg of force and the line is pre-tensioned tight at 180 degrees, the subsequent loading to the line and anchors must be in the region of 5000kg of force! That's enough to snap a well cared for 12mm double braid if the tree doesn't fail first! The best way to avoid such a catastrophe would be to snatch the top onto a topping block first and then clip it onto the speedline. The Speedline would then be tensioned and the section could be slid to the ground/truck. If yachting style fiddle blocks are used to tension the line, they should be removed before loading the speedline or they risk being damaged.

The speedline has its limitations - if a lot of tension is required to overcome the weight of a long run of line or gain clearance over a roof, smaller sections must be taken. If branches must be topped onto the Speedline, cut them on the small side and leave sufficient slack in the line to absorb the impact without high anchor forces. Letting the section run down the line will also help to distribute the loading better between the two anchors.

Choice of equipment is also important to a safe and smooth running speedline. Choose strong rescue pulleys with cheek plates that will not bind on the rope on the return to the climber. These can be used in various other rigging systems increasing versatility and reducing costs. Likewise with the ropes - I prefer a 16mm double braid as the speedline and a 12mm double braid as the haulback line. Always try and ensure that the Speedline is 1 and a half times stronger than the haulback - this enables some versatile techniques without dismantling the speedline, plus giving good safety factors.

On large spreading trees, re-direct the Speedline and the haulback rather than swinging the branch across the canopy. Alternatively, use a sliding tag line to control swing and retrieve the speedline from a side angle. Using a heavy carriage under the pulley running on the Speedline will help prevent the speedline from entangling with the haulback, therefore stalling the system.

Always be certain that the strength of the tree is not significantly compromised before deciding to employ a speedline requiring a lot of tension. I wouldn't advise speedlining dead trees unless the tension can be kept to a minimum. If in doubt, back stays can always be rigged.

It is difficult to explain the different systems any further in this context, but hopefully some fundamentals have been grasped and your speedlining operations will be safer for it!

Happy rigging.