The Truck-Based Gin Pole
Many fire apparatus in North America are equipped with anchor points around the truck specifically for rope rescue usage. This is most commonly found on heavy rescue units and those with special tasking for technical rescue activities. Practicality of these anchor points can come in many forms, and with the application of a creative mind they can serve many purposes. One of the more common configurations using truck-mounted anchor points is that of a monopod or Gin Pole. Some departments have pre-manufactured “kits” such as in the case of paratech. Others, have artificial high directionals such as the Arizona Vortex, or Terradaptor, and there are those who still employ an old fashioned ladder gin. Whatever gear is used, it is understood among most technical rescue teams, that they must have the equipment to incorporate their rig in to an effective high directional to mitigate calls in certain austere environments like a rescue from a bridge. In this piece we will explore an option utilizing the Arizona Vortex as the AHD, and a 54,000lb fire truck as the anchor.
There are a few rules to be followed with almost every gin pole. We know that the angles between the rear guying systems should be that in which the force on the guying anchors is reasonable, generally a relative 90 degrees or 120 degrees between guying systems depending on how many are used. We also know that in order for the gin pole to be stable, the resultant force created by the directional pulley on the head must be either perfectly in line, or just slightly forward of the compression member. Achieving these benchmarks can depend on a wide array of factors. How close is the gin pole to the rear guying anchors? How close is the gin pole to the main system anchor for main and belay? How far apart from each other are the anchor points on your apparatus? All of these can make engineering a solid, practical gin pole rather difficult. This is where using the features of your apparatus to your benefit, as well as applying critical thinking can prove to be the only ingredients needed to yield an exceptional rescue system.
Here is an example of a gin pole configuration rigged for a simulated bridge rescue. I would first like to discuss the guying systems of the gin pole because from a foundational perspective; poor guying, poor gin pole. This piece of fire apparatus has 4 rope anchor points on the top of each corner on the body. The issue with this, as is similar with many like apparatus, is the anchor point are simply too far apart from each other to allow for good angles between guying systems. How do you fix that? Well you could either move the gin pole much farther away from the truck, or the truck much farther away from the gin pole which would narrow the angle. I however, do not see this being a likely solution on the side of a bridge. As you can see, the way the angles were improved was to add a third guying system to split the angle between the two far ones. Remember, there are 4 rope anchor points on the apparatus. That leaves 2 unused anchors on the opposite side of the truck. We simply created a large two point anchor and laid it on the roof on the gin pole side. At that point a third guying system was easily able to be run from the head of the gin pole, to the anchor we fabricated by using the truck’s two remaining anchors. The benefit of this was significant. We were able to take an angle that originally created a force multiplier on our anchors, to an angle that decreased the force greatly just by adding a third guy.
Another point worth of discussion is how we use the features of our apparatus to give us the most “bang for our buck” in our rescue system. Imagine being on the side of a bridge with a rescue to conduct below, and your local law enforcement agency is adamant that the opposite lane of the bridge is to remain open so as not to totally shut down a major artery. We love our law enforcement partners, but their roads are important to them and sometimes they lack a little empathy for our operations. You are now faced with a situation inwhich you must find a decent haul field to bring the rescue package back up. Anchoring your MPD or other device directly to a wheel or side receiver and running straight to the gin pole will prove to be disadvantageous. The haul field would be tiny and resets would be plentiful. We mitigated this issue by using a side winch to create two change of direction anchors. Many rescue apparatus have these side receivers making this a practical solution for lots of teams out there. We elected to use a two-tension rope system. We anchored each of our MPDs on opposing sides one in front of the apparatus, and one behind the apparatus. These main system anchors can come in many forms, but the easiest would be other apparatus on scene positioned to the front and rear of your truck. Both ropes changed direction at the side winch receiver, and finally ran to the head of the gin pole. By doing this, both MPDs were able to be converted to haul and a lengthy sufficient haul field was created, with a total mechanical advantage of 6:1 hauling the load upwards ( two 3:1s working side by side).
Here is a closer look at the change of direction pulleys on the side receiver. Yes, one could look at this anchor as a “critical point” however we’re using a 9,000lb anchor to support a 600lb max load split between two rope systems. If this is too risky for you by all means make an adjustment but a wise man once told me to rig for the probable not always the possible.
To conclude, using the features of your rescue apparatus to make an effective gin pole system is a vitally useful tool to have in the toolbox. As long as we apply the constant rules of gin poles to our rigging our creativity can be endless in how we utilize our apparatus. Hopefully reading this presented a few good ideas to get started!
The author is none other than Jason Ilowite
Rigging Lab Academy Instructor | Firefighter in Loudoun County, VA
Peace on your days!
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