May 2010 Willie's Workbench: Winches, Part 2Posted in Features on May 1, 2010 Comment (0)
Willie's Workbench Winch rigging and safety In last month's column, I talked a bit about winch choices. This month, I'd like to continue on just a bit to make you think about proper rigging and safety.
Most probably (and hopefully), the instruction manual for your winch has safety and winching tips in it. The manufacturer put that manual there for a reason, so read the instructions and pay heed. No instruction manual? Check out the various manufacturers' websites for tips, or contact them to order a manual. Even YouTube has some winching tips that are worth looking at.
When working around winches and cables "Safety First" are the most important watchwords. Think what could happen if a cable should break or come loose with 8,000 or more pounds of tension instantly released.
Always run the "what if" scenario through your mind. Like what if the hook comes loose? What if the cable breaks? What if the vehicle doesn't go in the direction you want it to? There are a hundred other possibilities. On a serious winching operation-and especially when two winches are being used-there should always be a designated "safety officer" or commander of the scene. That person should have overall control of what is happening and station himself where he can see the entire operation-and the winch operators should be able to see him as well.
When spooling a line back on the winch drum, take your time and do it correctly. Don't say, "Let's put it on quickly and do it right later." An improper spooling job can lead to binding when you next need to use the winch, as well as damage to the cable itself. When re-spooling cable, the person guiding the cable should also be the one controlling the winch, and his eyes should never come off of where his hands and fingers are in relation to the cable and the winch. A finger torn off by a winch cable doesn't re-attach very well.
Remember the part about pulling capacity versus the layer of line on the spool? Let's say the extraction pull is a short distance, so you're on the top layer of cable on your 8,000-pound winch. You hook up the load, and due to the terrain, your winch doesn't have enough capacity. That's when you go to a double line pull using your snatch block. Not only do you double the pulling power, but pull out enough cable so that you're on the next layer of cable, thereby again increasing the pulling power of your winch.
Double line pulls using a snatch block are great. Keep in mind that the object that the snatch block is hooked to must move towards the winch. On self-extractions, the cable must be brought back from the snatch block's mounting location to the winching vehicle. If you hook it to another tree or anchor point, you're still doing a single line pull.
Snatch blocks can be quite useful, and I always recommend that you carry at least one with you, and two would be nice, along with the appropriate hardware to mount them. There have been times where two blocks were necessary to gain both the proper pulling angle as well as the needed capacity. It's very important that the snatch block is rated high enough to handle the load. Double the rated capacity is a minimum rating. Not only can they be used for a double line pull, but also for changing the direction of the pull. Generally speaking, due to the friction of the cable and that of the pulley, allow a 10-percent reduction in pulling capacity for each snatch block used.
Always keep in mind your anchor point, as you can easily double its load. The angle of the pull has a pronounced effect on the load not only on the winch, but on the anchor. Take a look at the examples below and I think you will be quite surprised:
When using a bridle to more than one anchor point, make sure that they are of equal length and that the included angle is less than 90 degrees. The lower the included angle, the less load on each anchor. As you can see from the diagram, when the angle exceeds 90 degrees, the load on each individual anchor becomes quite high.
So let me leave you with just a few thoughts. Safety is your number one priority. Always think about the "what if" scenario. Always keep your eyes on your hands when working with winch cable. Be sure of your anchor point's ability to hold, and be aware of the working angle of the cable. Thoroughly think out every winching operation before you begin.
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