There are a number of lowering devices designed for tree rigging available on the market today. In this article, we’ll look at best practices for using lowering devices in general and at specific tips for using three of the most commonly used devices, the Port-A-Wrap, the Good Rigging Control System (GRCS) and the Hobbs H-2.
The Port-A-Wrap is a portable, rope-friction device used to lower loads that a single ground person could not lower alone without additional friction. It was co-invented by Scott Prophett and Norm Hall. Buckingham Manufacturing makes it; Notch Equipment also sells a version, as does Bailey’s.
Here are some pointers from Norm Hall for use of the Port-A-Wrap. Hall has been working for more than 45 years in the tree care industry. He currently works at All Gear, Inc., as a splicer and trainer. He is also the lead instructor for the Illinois Arborist Association Advanced Training program’s “Tree Worker” domain.
Port-A-Wrap best practices
By Norm Hall
The Port-A-Wrap, commonly called the porty, is manufactured in four different sizes and will accept rope diameters from ½-inch to 7/8-of-an-inch, depending on the model. The device is mounted near the base of a tree using a rope sling. Different sling versions can be used, such as a spliced-eye, whoopie or loopie, but my preference is a spliced-eye sling. I prefer a spliced-eye sling because the throat distance can be minimized, keeping the device on the trunk right where it is mounted. If the device is anchored using a whoopie or loopie sling, it can spin the sling once loaded.
The Port-A-Wrap was invented to eliminate taking rope wraps on the tree trunk. This process involved coiling the lowering rope to take the appropriate number of wraps on the trunk, lowering the load, then coiling the rope again to unwrap it. The amount of friction was determined by the bark of the host tree. As arborists, we know that not all bark is the same, so the ground person had to be familiar with the various tree species in the area to be an effective lowering person. The Port-A-Wrap eliminates that problem, providing a constant amount of rope friction every time. There is no guesswork.
Here are a few tips for safely using a Port-A-Wrap.
• Always read the manufacturer’s instructions before using any tool or piece of equipment.
• Before anchoring the porty, figure out where the lowering rope is going to be anchored and mount the porty near the base, where there will be minimal limb interference with lowering rope.
• The Port-A-Wrap is mounted near the base of a tree around knee height. To anchor, I prefer to use a cow hitch, but when the sling isn’t long enough to go around the host tree twice, I use a timber hitch.
Note: Do not add a link to the long loop to anchor a sling (Photo 1).
• While tying either hitch, it’s important to leave the throat length as short as possible. Leaving a short throat is important during negative-rigging operations. This is because, as the log section falls, the Port-A-Wrap inverts and drops the same distance as the “fall” of the rigging rope. The shorter the throat length, the less shock (dynamic) loading there is on the porty and anchoring sling.
Tying proper hitches
Here are a few notes about tying the cow hitch and timber hitch properly.
The cow hitch starts as a girth hitch tied with the end of the rope, but is secured with a half hitch. The proper way to finish has the half-hitch tail exiting toward the bight of the hitch. Any excess tail can be tucked under either one of the sling legs, capturing the bight. (Photo 2)
When tying a timber hitch, we have two choices of making our five tucks. After the bight is formed, we can start our spiral tucks from the top or bottom. (Photos 3 & 4) Starting from the top will “add” tucks if the sling should roll up the spar during the lowering operation. Tucking from the bottom will “subtract” tucks should the sling roll up. (Photo 5)
Another consideration for the timber hitch is the direction in which it is loaded. The timber hitch works best when it is loaded against the bight of the hitch. When loaded against the bight, it puts force on the tucks, helping prevent movement. Loading with the bight will not let this occur. The sling can spin, and in some instances the tucks become turns instead of spirals, lessening bark contact and the effectiveness of the hitch.
I have found that by adding a turn on the throat, creating a round turn, it lessens rope creep at the throat, plus it increases the radius bend at the throat. I call it the “better timber hitch.” Five tucks are still required for the improved version. (Photo 6)
Ready to use
Once the device is anchored to the host tree, it’s ready to use. When the device is in its “at-rest” position, it is inverted. To install the lowering rope, grab it, position it upright, install a bight of the lowering rope through the angled loop and capture the bight of rope under the retention pin. (Photo 7) For heavier loads, additional wraps are needed. Make sure to wrap the lowering rope in the same direction as the bight install. (Photo 8) Taking wraps in the opposite direction will twist the rope, plus it makes a tight radius bend, which is not rope friendly. (Photo 9) The heavier the load, the more wraps are needed. Rarely are more than three wraps required. No different than any other lowering operation, always keep the excess rope in front of you, not behind you.
The long leg pins serve dual purposes. They prevent the lowering rope from sliding off the end, and they work as
lowering-rope cleat pins. If a lowered limb needs to be cut into smaller sections before being lowered to the ground, the ground person can take as many wraps as possible on the long leg and tie a half hitch around the long pin. The lowering rope must stay in contact with the round tube and away from the sharp edge. (Photo 10)
During negative-rigging operations, it’s important to have the lowering rope exit off the lower pin of the long leg. This is what happens during a negative-rigging operation; the log falls and the Port-A-Wrap drops the distance of the fall of the rope, creating slack in the lowering rope. The lowering rope is captured by the lower pin leg. If the lowering rope exits off the top pin, as the porty drops, the lowering rope can come off the lower pin, resulting in loss of friction. (Photo 11) I have witnessed this happen.
The Good Rigging Control System (GRCS)
The Good Rigging Control System, or GRCS, is a friction-control device used in lifting or lowering trees or tree parts. It was invented in 1997 by Greg Good, owner of Good Tree Care Company, a 27-year TCIA member company based in Hartland, Wisconsin, when he had the idea of using a yacht winch for tree rigging. It is manufactured by Good Rigging, LLC.
Pointers on using GRCS
By Greg Good
Every rigging situation an arborist deals with is also an engineering problem. We built our first winch system to solve a tree-removal problem that called for a crane, except the job site was inaccessible to one. More than a lowering device, the GRCS has been called a “crane in a box” by many users. Its built-in mechanical advantage gives arborists real power to apply to rigging situations.
All rigging operations need to begin with a thorough assessment of the trees to be worked on, followed by a rigging plan. We use a basic model for all of our rigging operations. Beginning with the size of the piece we wish to remove, we ask the following questions:
A. Is the rigging point sufficient to handle the load?
B. Which rigging technique will work best?
C. Do we have the equipment needed, sized and rated to handle this load?
D. Have we installed the equipment properly, and do we understand how to use it?
E. Do we know which cutting technique we need to use?
F. If we take a piece this size, will the ground crew be able to handle it and land it safely?
G. Does everyone on the crew know what is going to happen and what their job is?
If there is any doubt about any question of the model, we don’t make the cut. You can always go back to the beginning and make the necessary changes. Remember, you can always take a smaller piece.
The thing I tell people who get their first GRCS is to use it frequently, starting with simple rigging scenarios to get familiar with properly setting it up and operating it. The GRCS is designed to be simple and safe to use, but training is necessary. If you want to play a guitar, picking it up every six months won’t get you too far.
A GRCS is a significant investment, and many companies purchase one when they have sold a job they feel can’t be done without one. This can mean that someone may be attempting to apply an unfamiliar tool to a tough problem. Take time to get familiar with the device.
Watch the instructional video and understand the basic setup of the device. Understand that the rope fairleads must be used when lifting and lowering to make it safe and efficient, and they must be used every time. Watch the “Safety First” section of the video.
Use best practices with your GRCS:
• Don’t set up your GRCS directly under the rigging point; if the rigging point changes, move your GRCS out from under it.
• Remove the winch from the mount during setup and storage. Remove the winch from the mount when the climber is going to cut pieces and let them fall to the ground, i.e., as in cutting and dropping a branch stub after a large limb has been removed.
• Fold the pigtails down when not in use. Remove the winch handle before lowering operations.
• Always use the fairleads as shown in the instructions.
Tips for using the Hobbs H-2 and other lowering devices
The Hobbs lowering device was first designed and manufactured in 1980 by Ed Hobbs, and has been improved and redesigned over the years by Ken Johnson, according to a history of the device on the Bailey’s arborist supplies website. Bailey’s, a 30-year TCIA corporate member company based in Woodland, California, is a distributor of the Hobbs H-2, the latest iteration of the original.
The H-2 is designed for lowering lines from ½-inch to ¾-inch diameter, and has a working load limit (WLL) of up to 3,000 pounds. The H-2 has a lifting capacity of 1,000 pounds. The heart of the device is the aluminum spool, which is designed for extreme impact loading, wear resistance and heat dissipation. It’s mounted on a 1-1/2-inch, solid-steel shaft, with oil-impregnated bushings. The H-2 comes complete with a 20-foot mounting strap (fitting trees up to 6 feet in diameter), winch bar and detailed graphics explaining proper usage, ratings, warnings and safe operations.
Alan Precup, industrial sales representative with Bailey’s, provided the following tips for using the Hobbs H-2 and other lowering devices.
Overall
• Be sure to use rigging tools that are compatible with each other and are well within the WLL of the logs/branches you are lowering. WLL is the maximum working load designed by the manufacturer. This load represents a force that is much less than that required to make the lifting equipment fail or yield. The WLL is calculated by dividing the minimum breaking load (MBL) by a safety factor (SF).
• Keep the work area clear of branches and debris.
• Have drop-zone cones for additional safety and awareness.
• Inspect your rigging lines and slings regularly.
Port-A-Wrap (ArborMax)
• Make sure the rigging line is tight (sweating the line) before adding friction wraps.
• When negative rigging, let it run! (to dissipate the energy of impact and reduce the shock/impact on the tree and/or climber).
Advantages
• Simple and easy to use.
• Great for negative rigging.
• Reduces wear on rope.
• Low cost.
Disadvantages
• Cannot lift.
• Not fully attached to the tree; inverts when not under tension.
GRCS/Hobbs
• Limited ability to absorb impact/shock in negative-rigging applications. (GRCS more than Hobbs*).
• Allow for pre-tensioning the lowering line.
• Can lift the load/branch (GRCS, which has two gear settings for up to 3,000 pounds of lift.)
Advantages
• Greatly reduced potential for damage.
• Fully attached to base of the tree.
• Reduces wear on rope.
• Eliminates any shock or drop in rigging system.
Disadvantages
• More difficult to set up.
• Higher price.
Conclusion
Each type of lowering device has advantages and disadvantages, and which one to use for any one job will depend on the situation. Evaluate the needs, consider the options, then, as Greg Good advises, practice, practice, practice.
* Per Greg Good: “We don’t recommend using the winch component of the GRCS in extreme negative-rigging situations, but it has been tested in negative-rigging situations where a ¾-inch lowering line (20,000-pound tensile) repeatedly failed with no damage to the winch. The GRCS includes the interchangeable aluminum bollard, which can be used when extreme shock loading is expected. The aluminum bollard has been static tested to more than 40,000 pounds and is designed to allow the installation of an ice pack to help prevent heat damage to ropes.
“While the GRCS winch is rated for a dead pull of 2,950 pounds, we rated the maximum lift at 2,000 pounds, therefore not exceeding the safe-working-load limit of the ¾-inch-diameter lowering line, which is the largest rope recommended for the GRCS while using the winch component.
“With the bollard installed, lowering-line rope diameter is not limited.”
