Thinking One Move Ahead

On recent tower jobs I ran into several common mistakes by inexperienced ground crew. No matter how thoughtful, diligent or careful, novices at tower work regularly fail to consider the implications of what they deem a safe or clever procedure. It may be clever or convenient, but it can also be unsafe or create obstacles for those on the tower. Discovering why requires thinking one move ahead. 

In this article I'll enumerate a few of these mistakes and how to mitigate them. Those of you with tower experience can almost certainly think of others and perhaps better ones. Well, so can I. I hope that by walking through just a few that readers will get the idea. It isn't necessary to detail every situation and what works or doesn't work. 

By demonstrating the value of thinking ahead, anyone can analyze a rigging problem and avoid trouble. None of this precludes the benefit of group planning and communications. Independent thinking and improvisation are welcome but only if it communicated first.

Think of it as chess for towers. You will lose in chess when you fail to look at least one move ahead. Every choice has implications for what comes next.

Wrapping rope for hoisting

Beware of former boy scouts! They know exactly the type of knot to use in every circumstance. Unfortunately, when it comes to hoisting stuff up a tower, the knot is not the greatest concern. Indeed, in almost every case I use the simplest of knots: the half knot. It is one half of a granny knot, where there is one rope rather than two that need to be joined.

What usually matters more than the knot is the way the rope is wound. Consider the following:

It is rarely a good idea to attach the hoist rope directly to the object being lifted since there are often sharp edges or bends that can trap and cut the rope. I typically use shackles, carabiners or tow straps to grab the item, and the hoist rope is attached to that.

On the left is a rope on a shackle. There are two problems to consider. The first is that the rope will slide to one end of the shackle pin, which is hard on the rope and may imbalance the load. The second is that the knot will tighten under load. For heavy loads the tight knot can be very difficult to untie on the tower at the end of the operation. You do not want to struggle with an impossibly tight knot 100' in the air.

In the centre picture, both problems have been addressed. With the pin fully occupied the shackle won't easily tilt to one side. The knot will also be easier to untie. The reason is that friction increases with every wrap of the rope around the shackle pin. The knot experiences less loading and will tighten far less. More wraps can be better if there's room for them. I will often select a larger shackle than strictly necessary just so that I can wrap more rope on it.

The type of knot becomes less important when you do this and mostly serves to keep the rope from accidentally unravelling. Two or three half knots often suffice. The cheap polypropylene rope in these pictures can be stiff and slippery! Woven rope will compress more and offer more friction.

Once I show someone the difference additional wraps can make when it comes to untying the rope, they rarely forget. It helps them on the ground and it helps me when they send a load up the tower.

Although the spring-loaded carabiner on the right is easier to attach there may be insufficient room for even two wraps of the hoist rope. The bunched up rope can also interfere with the operation of the gate. 

Carabiners are easy to use but can be weaker than a shackle. I have a habit of hiding the carabiners so that my helpers use shackles. But I will pull out a carabiner where they are the better choice. I have an endless supply of shackles of all shapes and size.

Where to tie the hoist rope

This one is very common since it is tempting to hoist an item by the fastener that is meant to support it once installed on the tower. Consider the Kellems grip for LDF5 Heliax in the picture. 

The grip is convenient for hoisting the Heliax. It can work very well since Heliax is pretty light and even for towers well in excess of 100' (30 m) the Heliax can easily support its own weight. Once at the top, the grip can be fastened to the tower while the Heliax is secured to the tower with cable ties or more professional fasteners. There is no good reason to remove it afterward, where it serves as insurance in case the cable ties fail.

It is understandable that someone will connect the hoist rope to the grip. You will not easily remove a hoist rope attached to the Kellems up on the tower while it bears the weight of the transmission line. They must be instructed or shown another way, such as a second removable grip or with rope using what some call a "thousand yard knot". The picture in that linked article isn't very clear but I hope you get the idea. The same method also works well on mast pipe.

Wrapping cable while hoisting

This item is closely related to the previous one. It last happened a few years ago when I was raising guys for installation on one of my big towers. 

Typical of steel guys on a ham tower, they are broken into lengths that are not resonant on any amateur band for which there is an antenna in the vicinity. Resonant guys act like parasitic elements that will degrade antenna patterns. The insulators and grips add considerable weight to the guys. On a tall tower the lift can exceed 100 lb (45 kg).

There is a guy grip at the guy station to which the guy will be attached. That leaves a short length of guy flopping in the wind above the top insulator. The hoist rope is typically attached to that insulator. One of the ground crew wanted to prevent the short length of guy from flopping around and striking the tower on the way up. He did that by slipping the hoist rope over it in the fashion shown in the picture. 

It worked well for that purpose but it posed a difficulty. There is no practical way to remove the guy from that knot. Steel EHS guy cable is not very flexible and the rope is gripping it with a lot of force. I had to send the guy back down with instructions to be less clever. It was an understandable mistake. You need to think ahead for how the knot can be removed.

One alternative is to twist a short length of wire over both the rope and guy. That is easy to remove. Tape or an expendable cable tie can also work. A similar technique can be used with long masts that where the hoist rope must be tied below the centre of gravity.

Overuse of a mechanical attachment

I have no pictures to illustrate this one so I'll try it with words alone. The situation is that I show up at a job site and look over the work to be done and the materials prepared for me to lift and install. I will often find a few oddities. Let me give one example. Once you understand the situation you'll be soon spot others on you own.

I was asked to raise a length of hard line up a tower. It had to be mechanically supported, grounded for lightning protection and connected to the antenna. The grounding kit for the cable was nicely prepared and the hoisting grip was laced onto the cable.

The problem was that all of it was intertwined. The Kellems grip was bolted onto the grounding clamp for the tower and the carabiner for hoisting was attached to the grip (see earlier section). With this arrangement, the weight of the transmission line would bear on the grounding clamp. The connector would be difficult to align and mate with the antenna connector and (as before) there was no way to make it all work with the hoist carabiner attached to the grip and grounding clamp.

This was an attempt to make my job easier. I appreciated the thought but not the implementation. I unbolted the grip from the grounding clamp and moved the hoist rope so it grabbed the hard line below the grip. We then hoisted it up the tower. I first adjusted the position of the connector so that it would easily mate with the antenna connector. Only then did I attach the grip to the tower. The weight was borne by grip.

With that mechanical connection secure, I attached the grounding clamp to another tower member, allowing it slack to remove mechanical stress on the ground wire and hard line. Only then did I proceed to screw the connectors together. After the transmission line and antenna were tested on the ground we sealed the connections and tied the cable along the tower on the way down.

Overloading one mechanical device to do several jobs puts stress where it shouldn't be and complicates installation and maintenance. If the load shifts over time there is a high risk of failure. Keep the electrical systems separate from the mechanical supports, and from each other. Co-dependency only seems like a good idea until you work through the steps for installation and potential failure modes as the system endures the elements.

Where to tie a tag line

There are many places to attach a tag line to a load. It is typical for a novice at tower work to tie it at the bottom (3). It is easy to pull the bottom of the load with tag line attached there.

But is that the best place for it? Take a look at the adjacent diagram for several options, using a large tower section as a heavy load.

Let's review the purpose of a tag line: to clear obstacles during the lift, such as guys, side mount antennas and wires, and tower protrusions such as bolts. The tag line should be attached so that the load can be safely and easily steered around obstacles. Since visibility is limited from a large distance, that can be difficult with tall towers.

This is a bit of a trick question since the answer depends on the lift method, length of the hoist rope and the shape and weight of the load. There is no one correct answer. A small, light load is easy to steer regardless of where the tag line is attached. On large, heavy loads it matters a great deal.

Tied at the bottom (3), a heavy load is easy to pull with the tag line, but the top of the load might hardly move at all. If the hoist rope is attached at the top (1) the load can be steered but more force is required the higher it is. 

If the hoist rope must be attached below the top, as it often must be for long loads lifted by gin pole, the tower section will pivot around the hoist rope attachment, That can turn the top of the load into the tower rather than pulling it away. When the load is near the top of the tower it may be impossible to prevent the tower legs from tangling with obstacles, including the tower struts. 

This can be especially dangerous when machinery is used for the lift. The machine operator (which may be a car for amateur station) must pay close attention and obey instructions. Assign at least one member of the crew to keep watch and with the authority to order the procedure to stop.

Tying the tag line to the top of the load requires more lateral force to steer the load. When the load is close to the top of the tower that will place a high bending stress on the gin pole or mast where the pulley is located. I have seen this happen too many times. I can assure you that it is a very bad idea. Gin poles are vulnerable to lateral forces, and I have seen them bend or break due to excess enthusiasm by inexperienced ground crew. I appreciate enthusiasm but skill and foresight are better.

There is no universal solution to the problem. Each situation must be thought through, step by step, so that potential problems can be anticipated and planned for. Two tag lines can be useful, one for when the load at a low height and another for when it's near the top. Where obstacles or loads are particularly difficult, I follow the load up the tower to do what a tag line cannot. 

On tall towers I will rig the hoist rope so that the load is on the leeward side of the tower. When it is on the windward side more muscle is needed on the tag line to keep the load free of obstacles. It is not surprising that this detail is often missed by ground crew. They tend to choose whatever end of the rope is convenient. 

One experience of fighting the wind pushing a big load into the tower is usually sufficient for the lesson to stick. Tag lines can't work miracles.

Horizontal pulley

I've been using a pulley at the bottoms of towers for a long time. They are used to allow a vehicle (or other mechanical device) to power lifts. Many of the crew who assist me like it for manual lifts since it is easy to allow multiple people to pull when the extra power is needed. It came in handy during COVID lock downs to keep them further apart. 

Pulling on a vertical rope is easier to rig but it only allows up to two to pull and they must stand close together. That small additional setup occasionally inspires someone forgo the pulley and simply pull on the vertical rope when only one person is needed for a lightweight load. 

That isn't necessarily a bad choice, but it must be done with safety in mind. Too many hams will haul the rope while standing next to the tower, and directly underneath the load. Disaster beckons! If you must pull vertically, stand outside the fall zone. Don't stand too far away when a gin pole is being used since that puts unwanted lateral force on it. A horizontal pulley reduces the risk to crew and equipment.

Coiling rope

After the job is done the tools must be gathered and stored. One of those tasks is coiling the ropes. I use very long ropes for hoisting and tag lines on my tall towers. They can be up to 100 meters long. That's a job I prefer to avoid! I am fortunate that there is usually someone who is willing to take it on.

There are many ways to coil long ropes. Professional riggers use weaved rope that can simply be stuffed into a large container without coiling. It is very expensive rope that does not have a preferred "twist" and can be stored that way since it will not kink or knot when pulled out for the next job. Hams rarely use rope of that quality and expense, so it must be coiled.

This is a 100 meter length of polypropylene rope. Although it rapidly decays outdoors (not UV resistant) it is effective, cheap, and expendable. I will happily replace it or cut it into shorter lengths when it inevitably degrades from mishaps or the elements. I have better rope in my stock in lengths up to 200' (60 m). I am always on the watch for deals on high quality rope.

Twisted rope will instantly kink if you spin it over your hand and forearm, which is what most people do. You can get away with that for short ropes but not long ones. Most discover the challenge very quickly and are eager to learn how to do it better.

One method is to draw the rope onto a reel. For long ropes that can be tedious unless you build a stand for the reel with a handle for turning it. Occasionally I've done it by hand and it is no fun at all. For steel hoisting cable like aircraft cable, this method is almost mandatory.

Another and more convenient method is to lay the rope on the ground while coiling it. For long ropes it saves time to make it a large (long) coil. After it is coiled, it can be folded over on itself once or twice for compact storage. It may then be cinched by wrapping one end of the rope around the bundle. So far so good.

The trouble comes at the next job. Can you remember how many times the coil was folded? You might but you probably won't if someone else coiled it. Was the end of rope used to cinch the coil unravelled properly to the needed length? Was the rope stored in a way that the loops would not shift and interleave? In short, uncoiling long ropes can turn into a nightmare even if you have the "schematic" for how it was coiled.

Predictability is key. Try to supervise rope coiling to the extent necessary to achieve this objective. It is also helpful to identify and secure the rope ends so they are not tugged on in a way that creates tangles when it must be uncoiled. Use a bungee cord to wrap the coil rather than use the rope itseslf. None of these measures will guarantee successful uncoiling but you will have better luck.

Alternatively, have the person who coiled the rope uncoil it for the next job. Try not to grin evilly when you assign them this job!

Cable spools

Lifting cable is easier when it is tied into a spool. It can be control cable, steel support cable, coax or other wire. In more complex installations it is needed above ground rather than always running down to the ground. For example, cantilevered strut supports, phasing lines for stacks, distribution of control lines, etc. The spool can be lifted or, if it is compact and light enough, carried up.

When the spool is lifted up the tower I find that the cable may not have been spooled in a way that is easy or safe to work with. For example, when the spool of cable is tightly held together with cable ties. It can appear to those on the ground that this is an effective method to keep the spool intact during lifting. Those cable ties need to be cut on the tower. When that's done, the entire spool springs loose. This can cause problems.

Several times the cable was narrow and the cable ties very tight. I don't often carry small snips for cutting the ties, and they can be quite tough if they're of high quality. Slipping the blade of a utility knife (which I always carry in the tool pouch) under the tie to cut it risks cutting the cable. I must not only be very careful, those high quality ties may require a lot of force to cut the tie. The cable may kink.

Once the ties are cut there is nothing to keep the loose cable from escaping control unless I am prepared and first loop it over my shoulder or a convenient and suitable place on the tower, if there is one within reach.

It is almost always better to use electrical tape to hold the cable in a spool. It holds well and it is easy to peel off. I can also remove one or two loops of the spool at a time and wrap the tape back over the rest of the spool to keep it secure. That's probably the easiest and cheapest way to send cable spools up the tower. It suffices most of the time. Cable ties may seem like a good idea in this application but it only looks that way while the spool is on the ground.

There's more (lots more)

Finding examples to use for this article was not difficult. I'm sure that many readers will think of other examples, or alternative solutions to the ones I presented. It is an educational exercise.

In closing, I want to emphasize that all of these situations and mistakes are not criticisms. Inexperience can lead any of us to the wrong conclusions. It happens more often than we might want to admit. All of us had to learn, whether by experience or by instruction from those with more expertise. It is not difficult to forget those hard won lessons while on the job!  

The willingness to stop and think ahead pays dividends when doing tower work. Indeed, the same can be said for most life situations we encounter.